722.3 leaking @ rear end....where from? - PeachParts Mercedes-Benz Forum

ps2cho · #1 09-15-2011, 02:16 PM

I have a small leak on my 300TE that started a few weeks ago. Its just a drop or two every day, but I want to get it cleared up.

Its not from the pan -- somewhere in the rear.

What does that electrical plug do? It almost seems like its coming from there.

cypress · #2 09-15-2011, 03:46 PM

That is the kickdown solenoid. Take a look at my thread, mine had a major crack on it.

http://www.benzworld.org/forums/w201-190-class/1584951-leak-transmission-pan.html

Zulfiqar · #3 09-15-2011, 03:46 PM

seems like the kickdown solenoid is leaking, that big hex is a bolt with a couple of rubber O rings on it, replace them - I do recall seeing here on the forum that this certain bolt is now updated with a more chunkier version from mercedes benz just to eliminate this leak.

btw my car always kind of wets the trans from this area too, but my kickdown solenoid looks clean - maybe there is a vent up there somewhere.

cypress · #4 09-15-2011, 03:54 PM

Yeah, the overflow is up there....

Transmission overflow

ps2cho · #5 09-15-2011, 05:05 PM

If it is indeed the kickdown solenoid, do I need to drain the tranny to do it?

Its not coming from overflow. Fluid level is good. Sounds like the K/S is the culprit. I'll do some searching. Thanks for the ID guys.

JohnM. · #6 09-15-2011, 05:28 PM

I believe mine just started leaking there as well. I just did a flush, so I thought I had cross torqued the pan too much. But it's too far towards the rear for that. Neato.

cypress · #7 09-15-2011, 05:58 PM

Quote:

Originally Posted by ps2cho

If it is indeed the kickdown solenoid, do I need to drain the tranny to do it?

Its not coming from overflow. Fluid level is good. Sounds like the K/S is the culprit. I'll do some searching. Thanks for the ID guys.

Yes, you need to drain some. I drained all.

ps2cho · #8 09-15-2011, 07:02 PM

After reading your thread, it looks like I need to drop the pan to reinstall it? Is that correct? Or is that just if you install the whole solenoid?

ps2cho · #9 09-15-2011, 07:11 PM

Do I need the washer if the solenoid is not cracked like yours? (I'm gonna get it anyway, just curious)

cypress · #10 09-15-2011, 07:29 PM

No need to drop the pan or remove anything else. Would be easier job if you remove the cross member. I removed the cross member, just so I can check the surrounding area better.

Yeah, get the crush washer.

ps2cho · #11 09-15-2011, 07:48 PM

Gotcha. Looks simple

Will report back on success. I like how its $2.45 in seals too.

I changed to Redline Synthetic D4 10k miles ago when I resealed front pump since I had the entire thing drained of almost every ounch while on the bench -- so I guess the weakest seals go first!

Just to clarify though -- I DO need to remove the whole solenoid unit correct? Not just the bolt?

ps2cho · #12 09-22-2011, 04:00 PM

Got it off today...Looks like I have a small hairline crack too (EXACTLY the same place as yours cracked although mine is not as severe yet; weak point I guess?). I put the new seals on then put it back in, but it "looks" like I still have a few drips -- was hoping I wouldn't have to replace the unit, but it seems so.

I did it without removing anything. With a 6" extension + 19mm socket, you can remove the bolt and the whole unit just comes out with ease (30nm torque on install). I didn't drain the pan either. Once removed it streams out a little for about 1/2 quart. It just goes straight down into your pan below, so no worries about it exploding everywhere.

JohnM. · #13 09-22-2011, 04:38 PM

Mine turned out to be a pan gasket after all. But I pulled the kickdown solenoid from my spare tranny and it had a fat hairline crack in it as well. Seems to be an issue.....

ps2cho · #14 09-22-2011, 04:59 PM

Maybe that is the reason for the superceded part #....one can only hope!
I'll get it ordered and report back in the next few weeks.

ps2cho · #15 09-29-2011, 03:33 PM

Got the new part in a few days ago -- Leak resolved

The second time around it took me 20mins. This time did it facing downhill on my drive so less ATF came out. Removed bolt, pulled out, swapped in. 30nm torque, done!