Advice req'd:- shaft spline wear / measurements / possible fix 722.118 transmission
 

G'day Folks,

I've got a slight problem with a 722.118 transmission - BUT BEFORE YOU THINK oh I don't know about transmissions please read on because I'm looking for help with splines.

Statement of the problem:-

The only noticeable worn part on my transmission is a splined shaft in the front planet housing.

http://www.peachparts.com/shopforum/...1&d=1304069909

You can see in the picture above that there is a slight ridge in the first set of splines => towards the roller bearing race in the middle of the hole.

It looks to me as though the front planet housing has been shimmying on these splines as both sides of the splines are worn. As I've said before only the splines in the front planet housing are worn. The splines on the intermediate shaft (that fits into this bit) are fine.

Here's a picture of the two parts fitted together

http://www.peachparts.com/shopforum/...1&d=1307010486


Now the situation that I'd like to avoid is this one:-

http://www.peachparts.com/shopforum/diesel-discussion/297960-722-118-transmission-problems-stripped-out-splines.html

Where the splines have sheared right out of the front plant housing

Measurement of the wear in the splined connection
 

I've measured the play in the splines to be 0.26 mm

I did this by fitting the intermediate shaft to the front plant gear housing and wiggled the fitting and measured with a DTI

http://www.peachparts.com/shopforum/...1&d=1307010619

http://www.peachparts.com/shopforum/...1&d=1307010628

The point of measurement (the DTI probe) was 50mm away from the centre of the housing, and the splines are 14mm away from the centre. The measurement at the DTI was 0.91mm

A bit of trig tells me that I've got a wiggle of 1 degree (edited value - offending trailing decimal fractions removed)

How / why could / would this happen?
 

I'm not sure why this happens. It seems as though the splines on the intermediate shaft are much tougher than those in the housing.

I had a look for similar things on the internet and came up with these possibilities (although they aren't directly concerned with transmissions perhaps there's something of interest?) from one source

http://www.franklin-electric.de/en/pdf/aid/AID_1_2007_E.pdf

Where is says <QUOTE>

Reduced spline lifetime due to:
· Upthrusting conditions, i.e. pump operation at the very right hand side of the pump curve (large quantity, small
total head).
· Water hammering, high dynamic conditions in the pipe system.
· Frequent switching (on and off), such as with broken bladder in the pressure vessel.
Recommendation: Max. 20 per hour.
- Chattering relay contacts.
· Overpumping, possibly due to wrong pump selection, creating sudden changes in torque (pump discharge lar-
ger than well water supply).
· Motor back spin, resulting in increased shock loading on motor start-up (faulty pressure system, leaking check
valve).
· Excessive or insufficient revolutions (as a result of backspinning due to a leaking or missing check valve).
· Pump cavitation will shock load the splines and/or induce vibrations which may cause stripped spline or
accelerated spline/coupling wear (right selection of pump in accordance to suction conditions – NPSH).

<END QUOTE>

Can anyone add any more possible reasons / information?

So what am I going to do?
 

I'm multi-tasking folks!

Solution 1)

Asking the dealer to get me a new part => They've asked the classic centre in Germany for a price

{I expect this to be mega bucks}

Solution 2)

Making a scale drawing of the part and asking someone to CNC mill a new bit for me.

The drawing is nearly finished (and I'll post here if anyone else wants it) but I need an educated guess for material sort - can anyone here help?

Solution 3)

Find a good second hand part

Hmmmmmmm always a problem area - I'll end up having to buy whole gear boxes which I don't really want as nobody seems to split them.

Solution 4)

Glue / shim material

This is the main area in which I'd like to ask advice (see next post)

Solution 4 => Glue and shim advice
 

In this article

http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA091861

The authors talk about coating splines with a second material to improve wear characteristics.

Perhaps I could do something similar with a glue and / or shim material.

I only need to add about 0.26mm of foreign material to stop these parts from shimmying.

Volvo seem to be putting loctite on their splined shafts (see http://volvospeed.com/vs_forum/topic/144258-loud-bang-from-s70-awd-when-backing-up/ for example) but I'm guessing that for the gap that I've got this would be too much.

I think loctite might be too brittle.

So finally the real question:-

Does anyone know of a glue that is ATF proof - rubberised - heat resistant and strong enough to hold and fill a gap of 0.26mm?

Mini - update

A search on the internet gave this pdf

http://www.henkel.com.br/brb/content_data/SM_UK_211205.pdf

Looking at the spline misfit, it makes one suspicious that there is a very slight miss alignment through the transmission.
Often splines are used to allow for such unless they have an interference fit.

Use of some material to fill the gap generally does not work as the filler is softer than the parent metal. In your case, the shaft is harder than the damaged spline. Using some loctite product will not last long & then bits will float around & maybe block a control valve.
Probably some thing in the planetary is not perfect & the misalignment has shown on the spline.

You cant make everything rigid as there must be room for expansion & contraction, misalignment and end float movement.

As to what to do, if it was me, I would probably rub the sharp edges off & put it back together. I am a firm believer that unless its broken, dont try & fix it.

We have an old scraper here with a 6 speed Allison trans, some of its splines are much worse than yours & it has done many thousands of hours since it was last in pieces. There are no flex disks in the drive line either & it has a lock up on its torque converter so the splines in the trans get a beating.

Did the car have trans problems before you disassembled it ?
Was there clunking on power off/on ?
It would appear that the trans has probably spent much of its life changing between the intermediate gears & not much time in 4th.

Given the relative low mileage of your car, I wonder what has been going on to cause this & the other issues that you have uncovered.

As to our friend with the trans that has lost its splines, it must have been running bad for many 10's k miles to get like that.

Ah ha - thanks for that layback40 - Solution 5 is now on the board.

Answers to your questions (in order of appearance)

Did the transmission have problems before I took it apart?

Well yeah and no - I had a strange occurrence after an oil and filter change when I got nothing - no drive in any gear. I drained some and then added some and messed about and it sorted itself out

http://www.peachparts.com/shopforum/diesel-discussion/271207-1981-300d-auto-problem.html

The transmission was always a little clunky for my tastes but on the whole it worked quite well.

Was there clunking on power off/on?

More in-between if you were being too gentle with it. Decisiveness was the key to a smoother drive.

Given the relative low mileage of your car, I wonder what has been going on to cause this & the other issues that you have uncovered.

I'm pretty much convinced the car has been suffering from lack of use. I think it was owned by an elderly person (who probably had a dog!) who certainly spent a lot of money on body work repairs (new doors http://www.peachparts.com/shopforum/diesel-discussion/299274-w123-300d-door-retainer-question-csi-dating-exercise.html neatly welded patches in the engine bay http://www.peachparts.com/shopforum/detailing-interior/286358-w123-engine-bay-paint-advice-reqd.html and on the rear end http://www.peachparts.com/shopforum/bodywork-repair-paint-tools-tips-tricks/297314-w123-sedan-under-rear-bumper-panel.html)

Oh I forgot to say - measuring the play in the splines was quite a challenge as the planetary housing wiggled all over the place on the intermediate shaft. It didn't just rotate slightly on the splines but it kind of rocked on the end of it as well. So misalignment within the gearbox is most likely. The condition of the roller bearings however seems "as new"...

Here's a screen shot from the pdf linked in post 6
 

I hope this isn't going to upset Henkel but what do you all think of this stuff?

http://www.peachparts.com/shopforum/...1&d=1307024972

Layback40 makes a good point regarding expansion and contraction and also a good point regarding epoxy coming off and getting stuck in other parts of the transmission...

Can anyone else comment?

Has anyone else used epoxy based solutions like this before?

Here's a link to the one I guess I could use

http://www.rotal.com/_Uploads/355Hysol9466TDS.pdf

You can't take measurements with 2 place accuracy and then calculate 4 place accuracy. Assuming your logic/math is correct all you can say is your wiggle is 1.0 degree.

I don't know if that influences your actions but there is no validity to your last two stated digits and no decision should be based upon them.

Good point - I'm not particularly worried about the angle of wiggle - I wanted to try and gauge how big the average gap on the splined shaft is when assembled.

I'll edit out the offending numbers - thanks!

More information
 

I've been looking at the set up of the gear box and how virtually everything that does something is on this intermediate shaft. Take a look at the following parts picture I've made from screen shots (it isn't great quality):-

http://www.peachparts.com/shopforum/...1&d=1307037899

There is a lot of stuff that fits between the ends of the intermediate shaft

http://www.peachparts.com/shopforum/...1&d=1307037994

Now I can feel and see that both ends of this shaft wiggle. I guess it isn't surprising that they do as there are 3 brake bands operating on drums and two internal-drum clutches operating within the length of this shaft.

Unfortunately the ATSG manual doesn't specify any limits of play on the ring gear (part 592 in the first picture) and the fitment to the intermediate shaft.

I must confess - sorry layback40 - that I'm still leaning towards using some Loctite epoxy on the shaft splines. I think any play in the system will be taken up by the loose end at the other end of the intermediate shaft. But before I do so I'm going to do some calculations to see if the epoxy is going to be elastic enough for the gap I've got.

To be continued...

The epoxy does not sound to me like a good solution if there is a real problem. I would try to find a guy that has rebuilt tens of thousands of automatic transmissions over the years and talk to him.

Experience does count in this area I believe. If you could just get your hands on a blown simular transmission and check it's wear in that area is another option. Might be common for all I know.

No wear evident just use the parts in the junk transmission. Overall it should work out cheaper than buying new parts. Especially if the new fit tollerance is not much better than what you have.

At one time with mercedes transmissions you loose bolted them up and then centered them prior to torquing the bolts down. Mercedes got away from that eventually. In those days the drive system seemed super smooth. I believe they paid a lot more attention to the quality of manufacture of those vintage cars.

If you can identify the part numbers a stocking non mercedes transmission parts house may have it. Some of those transmission parts suppliers are huge. The part may only be a fraction of mercedes in house parts costwise.

Answer
 

If you plan to sell or junk the car this year it is OK.

Never use glue, plastic or epoxy inside an automatic transmission you want durability from..




.

I would be very hesitant to introduce any foreign substance. If you haven't already, peek at the valve body and think about the possibility for mayhem if something gets in there.

I take it you have looked on the euro ebays and there is nothing there? It just blows my mind that it can be so hard to get parts like this over there. When I was heavily into Triumphs I used to look forward to going to autojumbles and specialists like Rimmer and Moss when I was on business in the UK in the 90s.

X2
You are asking for trouble Army !!
Keep the snake oil out !!!!!!!
Look up the tensile strength of high tensile steel, that maybe close to what your parts are & compare it with the strength of the loctite stuff.
I would guess the loctite wont be 1/10 the strength of your splines.
It just wont work.
The first time you go off & on the throttle it will be all unstuck & the bits of loctite floating.


I lean towards you finding another trans & playing with it.
Your rough operation sounds like more of a vac or valve problem.
Its years since I have seen a 4 speed auto in pieces, maybe some one can comment on if this particular spline is meant to be an interference (press) fit or if it is a slide fit. I have an old 3 speed MB trans in pieces, it is not the same, none of the splines are as bad as yours.
My impression is that the car has been used for towing something heavy like a caravan in hilly conditions. Probably did not have fluid changes. That loads the trans up to the max with minimum lube.

Have you ever contacted the original owners?

I've not got in touch with the original Swiss owners - I'll look into it but I expect they've passed on.

There is no evidence of a tow bar ever been fitted. I've stripped and repainted most of the underside when I did the rear subframe.

Yeah I've cleaned out and reassembled the valve body - that's ready to go back in now.

As for parts - automatic gearboxes just aren't that popular. They do exist but everyone is scared to take them to bits so you can only buy complete second hand ones in "only low miles hardly used" condition... I just don't believe the sellers.

Thanks for everyone's input. I guess the snake oil is out. (Poor snakes they try so hard to please us)

Solution 4 and 5 are shelved for the time being. So no foreign material allowed...

I'll carry on with solution 2 => CNC machinists.

Can anyone help with material specification for this part?

http://en.wikipedia.org/wiki/Tool_steel

http://en.wikipedia.org/wiki/Category:Steels

They are probably made from an alloy that is then flame hardened.
I had a spline replaced on an axle a few years ago. The alloy they used to build up the axle was a much tougher material. it had to then have the spline electro eroded out of the built up metal before polishing the surface with a diamond grinder. It cost several $k . The alternate was a $12k axle.
A second hand dead trans from a location that is flat is probably your best & cheapest option.
I still think that spline would last many miles depending on how you drive the car.
Is that part of the trans the same as a later trans?

Yeah I live in a very flat land. Most people want about 300 euros plus for one that they say works. I'm always wary of these sorts of situations - lots of people call it a gray area - I think it is more likely people are trying to make as much cash from junk as possible... so far I've had my fingers burnt buying second hand parts here. Dishonesty reigns.

The 722.3 transmission is very different from the 722.1 it doesn't have the front planet set up at all.

If I were to be buying a second hand transmission I'd probably be buying a second hand 722.3 and modifying my car to get it to fit. But that project seems a bit much when I might get a few more years out of the transmission I've got.

The way I see it is that if I were to put it back together as it is (solution 5) I take the risk of an exponential wear on those splines that will result in violent failure. If I stick some glue in there (solution 4) I might delay this failure. I agree that it is a big might.

If I try to buy second hand transmissions - strip them down and perhaps get lucky I might spend as much money as getting the part made. Judged on my luck with second hand parts so far I think I'll be spending more that way.

I'm going to finish off my CAD drawing of the bit and see what the CNC chaps have to say about it.

In the mean time I'm taking barry123400's suggestion of finding some one who has done this before.

I agree that talking to some one who has had this problem previously is a smart move.
I am surprised that a CNC chap would want to make a new part. The should just remove the old spline, build up the part & cut a new spline.

It is surprising that you dont have a line of parts out of the middle east.
There are plenty of second hand late model 123 parts from there (Lebanon) that find their way over here.
Typically a good low km late model auto out of a W123 300D Turbo can be found for around $A600 with a 6 months replacement warranty.

What were the clutch packs like in yours?

My apologies about suggesting another transmission. Your location is obviously different. As you quoted it sounds like things are even a little worse where you live.

The transmissions are not a dime a dozen over here in north america either. Yet I suspect at least here with a little effort a guy can get his hands on one very cheap.

This ethic thing on used parts is simular over here. There are just too many people that find lying and other negative character flaws to be rewarding. So it is buyer beware in spades. Compound this with sellers just not having enough knowledge or experience to qualify things properly and you have bad situations.

I still feel the majority are fairly honest but the percentage of crooks is such you have to be very careful. I for example would never buy a motor on the ground.

The exception to that and about the only one might be from just a few members on our site. I know that if I sell something and say it is good it is good with no exceptions. If I tell you it is junk it is junk.

I have no wish to defraud any person or cause them to waste their time. Unfortunatly some people have such low abilities the bad dealing methods seem about the only way they can make their way through life.

I have to sleep at nights.

You make some very true statements Barry. Its the same world over.
One thing I like about this site is the way members are not scared to speak up (me included) & challenge any one who tries to be less than ethical in their dealings.
Ignorance is one thing, dishonesty is another.

The CNC blokes don't even know I'm going to turn up yet - I'm just working on the drawing. I reckon it would be quite difficult to repair the old part these days.

Firstly it is a casting that has been machine finished. Some of the casting edges look like there have been voids or air bubbles trapped during the casting process... that doesn't give me a warm wet feeling for starters... but then looking at the amount of metal around the splined shaft area - well I guess a new piece could be let in, but hmmmm, well, I don't know. May be 30 years ago when people were better skilled? I've just got a gut feeling a new bit machined from a blank might be less hassle in the long run. But when I speak to the CNC geezers I might be persuaded otherwise.

As for the clutch packs - it is almost a shame to replace them. The only reason I have is that they were actually quite cheap and I'd got that far into it. If I remember correctly when assembled the new clutch packs were about 0.1mm thicker...

The rest of the transmission (excluding the brake bands and these pesky splines) looks like it has just been round the block once or twice.

A little bit of progress
 

I've got this far with my CAD drawing. It is enough to show the CNC blokes what I need - I'm emailing this picture along with photographs to people to get some price indications.

http://www.peachparts.com/shopforum/...1&d=1307201479

As you can see it isn't quite there yet - but I'm not going to go any further just yet. It might not be needed.

I eagerly await the price feedback !!!
If I showed that to my local tool maker, he would hand me a mortgage application!! ;)

Yes I'm expecting a price quote between 500 and 1000 euros from the classic centre... I usually drastically underestimate these prices though. Even knowing what I know I expect I'll be shocked. I will be interested to see what the local CNC boys quote.

it will be an interesting one. If they make it out of a alloy steel & then heat treat it to try & get it hard enough, chances are it will deform badly. Making it out of a piece of hard (tough) material would be best except that it would need to be electro eroded as the machining could not be done even with a diamond cutter. This is the reason why I think the best repair would be to remove the spline, replace the metal with a super tough alloy & electro erode a new spline in. We have several of this type of repairs here, be it on much larger splines & they work well, thousands of hard hours without a failure of the repaired shafts & a hub.
My old 300D parts car probably has a good spline in it but the chance of me removing the trans over the next few months is very low!! I will one day just to see what 800k miles looks like in a trans.

Mini update:-

The local CNC blokes can't do it. They've recommended these people:-

http://www.tandwielen.nl/

I await a response!

Unsurprisingly I've been told that the cost of a custom made part would be in excess of 1000 euros... now that's a shame.

Thats cheaper than I thought they would suggest.
But I guess they do say "in excess" so thats kind of a open ended price ~ do & screw.
Now Army, may I suggest you go see your local cnc guy & see if he can just replace the spline on your part. I guess around 400 euros, but then I am not there.
Its a surprise that here isint a dead trans you can get the part from.

I'll take the part along to the CNC people and shove it under their noses - they're making something else for me anyway so I've got to go next week (or may be the week after - or perhaps the week after that!). I'll see what they say. They've already said no though and put me onto the people above.

As for a dead trans - yeah sure but that'll cost about 300 euros here only they sell it as fully working! ... OK I'm not being fair (not a very friendly comment) but of the places that keep the dead ones, that I've unearthed so far, they don't have the bit in stock. I'm also thinking that this could be quite a common problem with the 722.1 - those splines look way too poofy to me. Hardly a nice over engineered Isambard Kingdom Brunel job.

So I'm a bit stuck. I keep on thinking about the snake oil solution with the view that it might buy me some time whilst I hunt down a cheapish 722.3 to rebuild and then fit that at a later date... but then I think oh bollocks I'd rather have a DSG - now how could I get that to fit!




<Deep breath - I need one - and probably do too if you're reading this>



I could, as you say, just put it back together - but I'm not really happy with that idea. I might post a video of the amount of play the splines have when you fit the intermediate shaft in place and then twist the front planet assembly. It is not a pretty site.

Despite the "no no no - don't do it" comments - that I do agree with - and I thank everyone for making them - I think (may be - just may be) something has to be better than nothing.

Update
 

I just spent the day doing the rounds

No one will split a gearbox and sell me the bit I want. They all want in excess of 300 euros for a "one owner low mileage driven by a Nun on Sundays" second hand transmission... Hmmm do I feel lucky punk?

I've also shown the front planet assembly to several machining companies and even my engine rebuilding contact and they all say buy new. They won't touch it. They won't repair it. Like I said before 20 years ago it might have been different here...

So I'm back to snake oil again.

I'm awaiting a response from Henkel - who are not as quick to reply as other companies.

Another update!
 

Well I've just spoken with Loctite in the UK and they reckon I should be using 648

http://www.loctite.co.uk/cps/rde/xchg/henkel_uke/hs.xsl/fullproduct-list-loctite-4995.htm?iname=Loctite+648&countryCode=uke&BU=industrial&parentredDotUID=productfinder&redDotUID=100 0000IZXU

Bog standard anerobic adhesive.

I've been told that this is used by many expensive car manufacturers during the assembly of drive components to eliminate transmission clunks.

If I can't get hold of a good replacement bit in the next 3 weeks I'm going for the snake oil layback40!!!!!!!!!!!!!!

I'd given up hope but all of a sudden just like buses two came along at once!
 

I've been driving around the Netherlands today buying stuff:-

http://www.peachparts.com/shopforum/...1&d=1309619129

They are both 722.1s

One is a 722.118 furthest away in the picture

The one at the front is a 722.112

722.118 is for a diesel the other is off of a 2.8 litre petrol thing.

I'm gonna spilt these boxes tomorrow to see if they either of them have a good front planet assembly.

Don't ask how much time money and effort I spent today - I'm not going to publish that! But I will say I got them both for less than the "one lady owner from birth less than 60K km" ones they usually sell. Both 'boxes came with entertaining stories though of how they are perfect blah blah blah. We'll see!

Oh and just for fun look what else I picked up at a really really American price cheap:-

http://www.peachparts.com/shopforum/...1&d=1309619455

A 722.3. This one however is guaranteed not to work. Apparently it only shifts into first and reverse. Should be an easy fix!

So it now looks like I'll be fixing up 4 transmissions and selling 3 on. Anyone want to come and pick up a renewed 722.118, a 722.112, or a 722.3? Special rates for PP members - nice handy location for most members!

Army-

Good job. You might want to think about this factoid: the 722.112 (from a 280SE?) is a four speed box ( I have ,I think, a nice one I used to repair my 300sd 722.120 front pump). Perhaps that's the one you want to rebuild for yourself(?)

Rick

Do you think the .120 is a better gearbox? It seems a bit heavier... but that just might be oil...

From what I understand the valve body wouldn't match the behaviour of a (slightly) lower revving diesel engine would it? Also it has an extra rod on the right hand side - you can see it in the picture I posted above. I'm not quite sure what this does yet - I'll have to consult ATSG.

Anyway - early night tonight! I can't wait 'till tomorrow to see if this gamble has paid off.

Oh I couldn't go to sleep without knowing...
 

Luckily in summer you don't need to tinker by torchlight so I started with the 722.118 and got this:-

http://www.peachparts.com/shopforum/...1&d=1309635368

Very similar to the one that was in my 'box - bugger...




BUT - da da da da da DAAAAAAA!


on the 722.112 I got this:-

http://www.peachparts.com/shopforum/...1&d=1309635484

So if you are looking for this bit for your own transmission I can say this:-

1) Don't worry about getting the exact same transmission as the one you've got. You'll find this bit in any 722.1 series transmission

2) Looking at the ATSG manual it seems to me that this part will also be available in 722.0 - 3 speed transmissions

3) I think there is also a pretty good chance the 722.2 transmissions have this bit too.

And as I'm in such a good mood having found a second hand bit in good condition I'll even stick my neck out and make the following very non scientific guess - petrol engines don't shake as much as diesel engines, so perhaps there is a better chance of getting a good bit from an automatic transmission that has been connected to a petrol engine. (Don't bother buying a 722.118!)

You get 10 out of 10 for perseverance Army !!!!!!
Your comment about the difference with a diesel probably has some merit. The impact load when the motor fires is far greater. This is probably why the oil pump drives on the TC sometimes fails on diesel models. You would expect the TC to take most of the shock out of the drive though.
I am glad you have had a win. I was starting to feel guilty given my old 300D (1980) has its trans still in it. But then its coming into winter here ~ cool & raining today, the thought of pulling a trans out is depressing.
I have enough stuff to do & get done on machinery as most are not working now because of the weather.
The 722.3 is probably potentially the best of what you have. Rebuilt, it wont have many of the change problems of the earlier ones.

I hope those trans all came with their TC !!

Oh yes - I made sure of that. I'm going to check the numbers but it looks like the torque converters for the 722.1 and 722.3 are the same, which is a shame as I understand these torque converters don't lock at higher speeds; so they always have a bit of power loss.

They shouldn't be. The .3 has much stouter fingers that drive the oil pump. If you can get that one to work, use it (of course, you already have all the bits to redo the 722.1s, don't you?)

I forgot to say. I got a response from the Belgian branch of Loctite and they reckoned I should be using 660

http://www.henkelna.com/SID-145508E5-6ADEF992/industrial/loctite-videos-12944-12974.htm

So if you're going to go down this route - take your pick folks!

You like your snake oil Army !!! :eek:

I thought I might get a reaction like that. It was worth posting the information!

I am just trying to avoid having you rebuilding a trans for the second time !!

Your help is much appreciated. Now that I've got 4 non working transmissions in my garage it looks like I'll be getting some practice!

Have fun !!!

Best keep them in the 4 corners of the garage. Avoid too much parts interchange !!