717.412 (5 speed manual gearbox) refresh - Page 2 - PeachParts Mercedes-Benz Forum

JB3 · #16 07-14-2013, 03:03 PM

the biggest thing I can recall is do not forget the thrust washer that goes behind the overdrive gear when reassembling, at least on the 411, looks pretty similar for the 412. I also had a few springs I blundered and had to take apart and reassemble a few times.

you will be extremely upset if you forget that thrust washer.

The whole thing will go back together beautifully, will shift into every gear on the bench, and when you try and put power through it, the overdrive gear will be jammed into the case and create a horrendous noise.
example of the missing thrust washer in use-
1st test drive of 1980 240D with 1984 190E 5-speed - YouTube

The 412 and 411 seem virtually identical! I see little difference between them, apart from that impeller (which I can't find a pic of)

Stretch · #17 07-14-2013, 05:46 PM

I think I found that thrust washer in the bottom of the casing - thanks for the tip. I'll check back with you before I reassemble the gearbox if that's OK with you.

JB3 · #18 07-14-2013, 06:02 PM

Quote:

Originally Posted by Stretch

I think I found that thrust washer in the bottom of the casing - thanks for the tip. I'll check back with you before I reassemble the gearbox if that's OK with you.

no worries!

so there was a little flat bearing thing between input and output im seeing? interesting! Im glad to get an idea of what was there

this is what was in my .412-

Im assuming this is a towing destruction, because you can see that the transmission got so hot that the actual synchro expanded enough to pop out of the splines and actuall sit on top of them on the piece on the right. Its a solid piece now.

The very end of the output shaft was snapped off in the input shaft. I don't think its possible to do that much damage actually driving the thing, most people would stop immediately and couldn't reach the levels of heat this thing apparently met. There are heat marks on the synchro lever all the way back to the side of the case.

Stretch · #19 07-15-2013, 02:51 AM

Towing? Well I get what you are saying about the heat and probably noise - but people are stoopid they will try and drive away (from the cops!) with no wheels. May be there wasn't enough oil in it and then combine that with the absolute necessity to get to Grandma's house...

Stretch · #20 07-15-2013, 02:54 AM

Perhaps useful for in a bit

Stretch · #21 07-15-2013, 02:55 AM

Might need a favour in a bit!

JB3 · #22 07-15-2013, 09:03 AM

Quote:

Originally Posted by Stretch

Towing? Well I get what you are saying about the heat and probably noise - but people are stoopid they will try and drive away (from the cops!) with no wheels. May be there wasn't enough oil in it and then combine that with the absolute necessity to get to Grandma's house...

My thinking is the damage to mine is consistent with the vehicle being towed with the rear wheels on the ground and rotation being applied in reverse into the gearbox, with the output shaft spinning, but the countershaft remaining idle and no lubrication being thrown up on the higher gears.

You are right though, people will cruise around with massive issues oblivious, so it definitely could have been cooked by red riding hood on an innocent errand.

winmutt · #23 07-15-2013, 11:42 AM

Great writeup!

JB3 · #24 07-15-2013, 01:26 PM

Quote:

Originally Posted by winmutt

Great writeup!

agreed!

Im waiting for him to get to the 717.400, but I see a whole series of take it to bits threads authored by stretch.

Stretch · #25 07-15-2013, 06:51 PM

717.400 - why would I want one of those? I've just rebuilt my 722.118!

HYMER DAVE · #26 07-15-2013, 08:43 PM

Hi Stetch, not very good with boxes but that was a mint bit of reading, dave

Stretch · #27 07-16-2013, 02:53 AM

Dave this is the easy bit - anyone can take it to bits - as Tom says back on page one you need to put it back together again. Watch this space!

Stretch · #28 07-16-2013, 09:37 AM

The reading material and adjustments information is in.

Thanks goes out to those who are helping me behind the scenes - I would name you but a good spy never reveals his sources of information! For reasons of privacy I'll not name you unless you want to be known - even though I'm getting my hands and my camera dirty I couldn't do this with out you - no man is an island, so thank you all very much.

Stretch · #29 07-16-2013, 11:14 AM

After cleaning the outer casing and starting on the inside I've discovered that three of the four tapered bearing cups that fit in the casing spin round...

...bugger...

...I can't leave them like that. The point of the bearing is that they spin on the taper bearings not on the cups in the casing. I'd rather not peen them in position so I'll probably have to dismantle and glue them in place...

...unless of course someone else has a bright idea.

So QUESTION =>

What would you do?

Simpler=Better · #30 07-16-2013, 11:52 AM

Quote:

Originally Posted by Stretch

After cleaning the outer casing and starting on the inside I've discovered that three of the four tapered bearing cups that fit in the casing spin round...

...bugger...

...I can't leave them like that. The point of the bearing is that they spin on the taper bearings not on the cups in the casing. I'd rather not peen them in position so I'll probably have to dismantle and glue them in place...

...unless of course someone else has a bright idea.

So QUESTION =>

What would you do?

I'm assuming they're "square" bearings? Or a tapered housing? Can I have a picture?

I would try to hold them in mechanically, with either a press fit or deforming something to hold them in place. I don't have much faith in adhesives holding while submerged in oil, heated, and constantly vibrated.