Help - stuck on road 722.3 no 3rd/4th gear - Page 2 - PeachParts Mercedes-Benz Forum

Stretch · #1 11-14-2011, 02:02 PM

Quote:

Originally Posted by Merkey

...
One thing I did spot that we may have missed, is that there is a small threaded shaft called the "Axial Support" that passes thru the secondary pump, and is secured with a nut. The end of this shaft has a small slot in the end, and in one of the manuals(which I just found) it mentions making sure that the slot is horizontal... There is only about 45deg or less movement in this shaft, and its slot, and horizontal is at its maximum clockwise position.

Whilst tightening the nut would rotate the shaft to its stop position... which would be horizontal, I am unsure where we set it, as I only just fornd that info...
Anyone know what the Axial Support does?

...

Bang goes the governor theory then - though a dodgy one might explain some of the other problems your son has been experiencing (see the other posts).

Anyway I can't see the axial support in the ATSG manual (I'm on page 31 and 32 at the moment looking at the secondary pump removal and installation)...

and I can't see it on the parts diagram here =>

http://www.ganzeboom.net/images1/ganzeboom/parts/Mercedes/722.3,%20722.4.pdf

Can you post some more information on it or tell me which part number it is in the pdf file posted above?

In a worst case scenario I can take a 722.303 to bits at quite short notice to get some pictures for you guys if you need 'em. Stripping that one down is on the to do list anyway - I can just bump it up the list if you think it might help.

Quote:

Originally Posted by Merkey

...

I am also concerned about a failure of the Kickdown Solenoid...
Anyone know if it fails in the open position, and what the result would be?

What I find odd, is the way this problem manifested itself... The drive was uneventful, and almost 300 miles long before he slowed down, and only then did the trans start acting up...

To eliminate the kick down solenoid you should just have to disconnect it. It you are worried that it is sticking they seem to be pretty simple things. Just remove clean and inspect - bit of grease if you want to be 100% sure it is moving as it should.

Hirnbeiss · #2 11-14-2011, 07:20 AM

Placing bets on Kickdown Solenoid to win before it's post time.

Stretch · #3 11-14-2011, 08:08 AM

My bet is on the bit that has been removed and replaced => the governor.

My limited understanding of these transmissions leads me to think that the governor would be better off being called the "manager" (or think of it as old fashioned English slang where the boss / manager was often called "governor" or if you're from Northern England "Gov'ner").

Anyway if you look through all of the faults with shifting remedies in the ATSG manual you'll see governor as a possible problem area for (virtually?) every fault.

I think if the governor doesn't work; the fluid (at pressure) doesn't get directed correctly. I think it goes to failure mode where nothing or little is allowed to engage.

huthrestorations · #4 02-26-2014, 01:22 PM

Hello all, just figured I would share something to save someone a big headache. I just fixed a 722.3 transmission on a 1991 350 SDL w126 that would not shift out of 2nd gear, car only has 80k miles on it. I don't know where it came from but a small piece of plastic got sucked up into the secondary oil pump and jammed it causing the end of the pump shaft to shear off leaving all kinds of damage and metal pieces, it also sheared the hardened pin off inside the governor. Dealer wanted over $400 for the oil pump and almost $300 for the governor.

The fix was to eliminate the secondary oil pump by buying the block off plate, gasket and screws from the 1992 S350 Diesel W140 body from the dealer (PARTS TOTAL WAS $36). Then I brought the Governor to my friends machine shop and we drilled through the collar of the gear and a tiny bit into the shaft, tapped and installed set screws with locktite and peened the heads.

Transmission shifts like new again...

ps2cho · #5 11-14-2011, 09:23 AM

To clarify -- the governor is what the aux pump connects to?

Once I get her home I'll take the pump off again to try and figure out what's going on.

I'm just hoping I don't need to rebuild the whole thing...

berryrice · #6 11-14-2011, 03:27 PM

Ph2cho, Huge bummer! I currently have my tranny down and just did a partial rebuild. I'll be re-installing it later this week. Your post and site have been a great help. If mine goes belly up then I've lost 250 bucks in parts and time. Then I'll just buy a rebuilt tranny. Good luck and let us know the outcome.

ps2cho · #7 11-14-2011, 09:49 PM

The 300TE is the garage safe and sound now...so I got under the car to try again.

So you can all see it. #43 + 44 show the different positions.

I took off the nut and attempted to get it to lock in place, but was unsuccessful. I am not sure if its a tight fit, or I need a better tool, I don't know. Maybe someone who has done this step can pipe in and say how they did it or if it was tight.

Stretch · #8 11-15-2011, 03:41 AM

Are you guys now planning to remove the governor and start over?

(It seems like a plan to me)

ps2cho · #9 11-15-2011, 09:47 AM

That's the plan for me. Gotta unbolt exhaust to drop tranny down. Just not enough space...

I really need to confirm the gov is not stripped.

I am reading there is snap ring inboard that requires an mb tool to release...any alternative?

pmckechnie · #10 11-15-2011, 12:49 PM

Removed the governor from my 91 300D a few years ago. I know the clip was a little hard to get to but I used needle nose plyers and long thin screw drivers. I found the gear broken (plastic). Cost of part was less than $2 before tax from dealer. My car has 1st gear start so it stayed in 1st. Remove the rear crossmember and let trans drop as far as it will. Push the trans as far as posible to the right side of the car and put a block of wood somrwhere to hold it there. Remove the snap ring that holds the gov cover and remove the cover. Try to turn the gov and if it turns than you have found the problem.

It is very important that you keep the gov clean. Also, If the gear is broken or stripped than check the rear pump before you reinstall the gov. The gov gear also drives the rear pump.

That is all I remember from when I had mine out. That was about 5 years ago.

Paul

ps2cho · #11 11-15-2011, 02:11 PM

Thanks! So its possible to get the governor out just by pushing the transmission to the side? Is there enough space to get the clip with screwdrivers then?

I'll give it a shot and see what I can do.

Stretch · #12 11-15-2011, 02:14 PM

Quote:

Originally Posted by ps2cho

Thanks! So its possible to get the governor out just by pushing the transmission to the side?

I'll give it a shot and see what I can do.

If you have a spare hand - perhaps you can take some pictures for us?

sba121400 · #13 11-15-2011, 02:58 PM

I have had two incidences with the governor and secondary pump in two of my cars. Since it sounds like the axial support was not in the right position, it allows the governor to move back and forth, once the car was brought out to speed the the governor will stay in position, but if slowed down and put in lowerr gear the governor will move around. On the opposite side of secondary oil pump sits the governor, there is a cover over the governor, This is where the governor is most likely pushed against and is stuck. There is a gear on the governor which if metal would of broke the small pin located on the governor making the governor rotate freely not up-shift. If the gear is plastic it would of broke and will need to be replaced. The car will have to be towed or driven in 2nd gear to a shop, the transmission will have to come out to open up the rear end of the trans and assess the damage.

Any Question, just Ask
Sean

ps2cho · #14 11-15-2011, 03:30 PM

Alright, I tried to get that governor cover off and it won't budge in!! Unless its supposed to be tough? All of the rest of those covers press in 1/2in, but this wont.

My thinking is that the governor is pressed up against the cover. So I went first to the pump to check it:

Phew...looks OK!! Seems that the pump engaged fine, so its gotta be with the governor and I HOPE that since I don't see any damage, the governor just slipped sideways towards the drivers side and no damage occurred.

I tried to get a photo of the output shaft of the gov but its pressed in (AGAIN, strong indication its too far over.) I couldn't get a good photo, but it looked okay too.

ps2cho · #15 11-15-2011, 04:21 PM

Got it now!

What do ya know...governor spins

I'm thinking the diagnosis was correct!

Gonna try now and get the governor out without dropping exhaust, and if not I may just try and reposition the governor, lock it down and give it a shot.
Curious though why there seems to be rust? Does this end of the governor not get fluid?

I am trying to find what position/orientation the governor is supposed to be in when reinstalled. Anybody know?