722.315 transmission questions - PeachParts Mercedes-Benz Forum

Maximan1 · #1 11-13-2018, 01:43 PM

Hey all,

I have a 722.315 transmission that came with my free Craigslist OM617 which I am rebuilding to swap into my 1979 240D. I was told by the person who gave me the trans that it was slipping, and I found the source of a pretty decent sized leak which I think could cause the trans to lose enough fluid for it to start slipping. Someone had removed the dipstick tube without removing the bracket that held it down, then smothered the whole thing with what looks to be an entire tube of red RTV. Big leak from there, but the rest seems alright.

My question is, how robust are these transmissions? I do not want to rebuild a transmission that may not need it, and I don't want to tear into it if these are known for long life. Is it smart to gamble on the idea that the trans was slipping from fluid loss by the dipstick tube?

The fluid in the torque converter came out pristine, I have not pulled the pan off yet - I want to finish the engine rebuild before touching the trans.

What should I look for when I get started with the transmission? Would it be a wiser choice to simply start looking for a good used transmission instead of screwing with this one?

Last thing I want is to put everything back together and have to pull the trans back out.

Thanks
Max

Stretch · #2 11-13-2018, 01:53 PM

Quote:

Originally Posted by Maximan1

Hey all,

I have a 722.315 transmission that came with my free Craigslist OM617 which I am rebuilding to swap into my 1979 240D. I was told by the person who gave me the trans that it was slipping, and I found the source of a pretty decent sized leak which I think could cause the trans to lose enough fluid for it to start slipping. Someone had removed the dipstick tube without removing the bracket that held it down, then smothered the whole thing with what looks to be an entire tube of red RTV. Big leak from there, but the rest seems alright.

My question is, how robust are these transmissions? I do not want to rebuild a transmission that may not need it, and I don't want to tear into it if these are known for long life. Is it smart to gamble on the idea that the trans was slipping from fluid loss by the dipstick tube?

The fluid in the torque converter came out pristine, I have not pulled the pan off yet - I want to finish the engine rebuild before touching the trans.

What should I look for when I get started with the transmission? Would it be a wiser choice to simply start looking for a good used transmission instead of screwing with this one?

Last thing I want is to put everything back together and have to pull the trans back out.

Thanks
Max

As transmissions go for that generation of mechanical + hydraulic actuated transmissions the 722.3 is a tough unit.

However, as it has been slipping - and allowed to slip - damage could have been cause that would involve a rebuild.

The guess about the dip stick seems to me like a good guess

I don't think that anyone - sitting in their armchairs can say if the transmission wil be good or not. It is a bit of a lottery - but what have you got to lose? Just a bit of time fitting it to see if it works. Put it this way the more often you remove and refit engines and transmissions the better and faster you get at doing it!

(Small print:- I know I'd be pulling it to bits but I'd like to think I could take the gamble and just see - I don't think (the self diagnosed) OCD would allow it though)