Kickdown Solenoid - leaking? - PeachParts Mercedes-Benz Forum

BENZOMANIAC · #1 09-10-2006, 01:47 PM

Hey All!

I have this tranny leak in a 87 300E that I thought was coming from the kickdown solenoid. I replace the o-rings and crush washer and re-installed. Still leaks.

My question- Is there any fluid in the kickdown solenoid magnet coil housing? By design it looks like fluid passes through the bolt/valve but not in the solenoid housing. So there is no way it can be leaking, right? I bought a new solenoid housing but didn't install it because I noticed the fluid flow design when it was out.

BTW - Does anyone know if the case seal that is on gear selector and behind the neutral safety switch can be replaced with trans in car? This looks like the only other place that could be leaking.

BENZOMANIAC · #2 09-10-2006, 09:47 PM

Any 722 Tranny pros out there?

Strife · #3 09-11-2006, 12:37 AM

I have a spare one for my transmission and it looks like a coil made in cast epoxy - I can't see it leaking unless actually cracked.

BENZOMANIAC · #4 09-11-2006, 01:15 AM

Hey Strife,

Are the Orings on the solenoid bolt for dust, or fluid? Is there fluid in the housing around the bolt or for dust? My old solenoid has a rough mark in surface where the outer-most o-ring sits, but so does the new one I just bought. I didn't install it because I am going to send it back for another as I don't think the inner hole should be rough/paint flaking, like that. I'll try and get a clear enough pic tomorrow to post.

david s poole · #5 09-11-2006, 10:45 AM

first you shouldn't use crush washer between solenoid housing and trans case.the o rings are designed to seal and use of crush washer affects the depth of solenoid in the case.you need to check the large o ring or replace it and yes the selector shaft seal can be replaced from outside.

BENZOMANIAC · #6 09-11-2006, 12:45 PM

The Crush washer is factory and I replaced with new one from dealer. I don't understand how the trans case to solenoid connection wouldn't leak without the washer installed.

C32AMG · #7 09-11-2006, 09:26 PM

Behind the neutral safety switch you will also find the B2 reaction valve which is a source of a fluid leak, the internal o ring can not be change externally, if it’s leaking clean the valve and case then use a good sealant on/ over the reaction valve.

The KD solenoid valve/ bolt should have three o rings on it if not you are missing some. The electro magnetic body should not have oil in it, if it does the o rings are leaking or the body has a crack in it. The electro magnetic body has/uses a washer between it and the case which seals the case and body from fluid leaks and also sets the depth of the solenoid valve into the case, without the washer the fluid feed to the solenoid valve/ bolt may, could be partially block affecting KD shifts

BENZOMANIAC · #8 09-11-2006, 09:42 PM

Thanks for responding C32AMG. I replaced the three orings with new and crush washer as well. In my case, the shaft is getting wet inside of electro magnetic body , so maybe the electro magnetic body is cracked.
I will carefully install the new one and hope for the best.

C32MG, Do you know what spec the bolt should be torqued to?

I will also pull the neutral safety switch to see what I can do.

BTW, do you know how to change the gear selector shaft seal? Anything special?

C32AMG · #9 09-11-2006, 10:34 PM

Torque on the bolt is 13 ft-lb. there is a universe tool, but there is no space with the Trans in the car, in the field you have to improvise, I use a thin but strong flat head screw driver, I sharpen the tip but still flat .tap the screw driver between the seal and shaft and pop the seal out. Be careful not to nick the shaft, if you do, dress it up with 220 sand paper. To install tap the seal in with a socket. Buy two seals just in case, once you do a couple it’s easy.