Did the Transmission quit on me? SA, Tx - PeachParts Mercedes-Benz Forum

Stretch · #1 07-26-2012, 07:01 AM

Here's some information on taking your existing transmission to bits

http://www.peachparts.com/shopforum/diesel-discussion/304903-722-118-automatic-transmission-rebuild-monster-diy.html

I reckon you've got a 722.118.

Changing just the front pump and replacing the torque converter sounds like it might be a good fix.

However, you might also have worn splined shafts - see thread link above for more information - in which case you either need to find a replacement 722.118 or a different 722.1 for parts.

Fitting a 722.1 transmission not designed for your car will cause difficulties such as shifting points, throttle linkages, and vacuum system.

If you want to see which transmissions (say a 722.3) that will fit your car I might have the information you need here

http://www.peachparts.com/shopforum/general-information/311136-fsm-epc-data-%3D-chassis-model-transmission-drive-train-information.html

81-300d · #2 07-26-2012, 01:45 PM

Quote:

Originally Posted by Army

Here's some information on taking your existing transmission to bits

http://www.peachparts.com/shopforum/diesel-discussion/304903-722-118-automatic-transmission-rebuild-monster-diy.html

http://www.peachparts.com/shopforum/general-information/311136-fsm-epc-data-%3D-chassis-model-transmission-drive-train-information.html

That DIY monster trans rebuild thread is AWESOME. I keep refering back to it thinking...maybe, just maybe, I could rebuild my trans. Not to keen on the idea of taking the transmission in and out, in and out, in and out trying to get it right. Or worse, blowing the transmission up cause-I done - did it wrong.

I found a throttle modulator controled 722.118 for $150, but I passedn on it because mine is vacuum. Definatly having second thoughts about that now.

Thanks for the trans interchange link.

Do you have an idea of why the pump would go out, something inside binding (brake band)??? The pump seems like one of the simplest parts in the transmisson and mine failed while idling. I think it was on your thread that pointed out that the torque converter tabs were the weak part.

And lets say

I might have towed my car 30miles at 50mph thinking the pump wasn't the problem. Do you know what damage I could have done?

Stretch · #3 07-26-2012, 02:51 PM

Quote:

Originally Posted by 81-300d

...

Do you have an idea of why the pump would go out, something inside binding (brake band)??? The pump seems like one of the simplest parts in the transmisson and mine failed while idling. I think it was on your thread that pointed out that the torque converter tabs were the weak part.

And lets say

I might have towed my car 30miles at 50mph thinking the pump wasn't the problem. Do you know what damage I could have done?

The front pumps + torque converter tabs on these transmissions are known for it. Known for being weak. The next real series of transmissions the 722.3 had a totally redesigned front end...

The problem with towing these transmission from what I can make out is related to the secondary pump. This one drives from the output shaft and is turned by the rear wheels. Apparently you are meant to be OK so long as you stay below 30 MPH and go no further than 50 miles

http://www.peachparts.com/shopforum/diesel-discussion/224996-i-need-tow-dolly-my-300d-40-miles.html

I'm not 100% sure why you shouldn't go faster than 30 MPH - I'll look into it.

(It is probably going to be something to do with the secondary pump producing too much pressure and if the engine isn't running it is trying to turn the engine backwards via the torque converter)