Changed tranny filter, now pan won't seal! - Page 2 - PeachParts Mercedes-Benz Forum

mplafleur · #16 07-30-2002, 05:45 PM

Last night I took it all apart and it looked ok. I cleaned the pan and made sure the dog-ears were straight. I put sealant on the mating surface of the gasket and tightened all bolts in a star pattern to 6 ft-lbs. One dog ear wanted to push out, so I loosened up the bolt and pounded it back into place. Everything looked ok so I put in the 3 1/2 quarts of ATF that I had, checked for leaks and drove around the block a few times. No leaks.

This morning I drove off to work and it slipped out of gear after about 6 miles. I looked and saw it was leaking again, only at the rear. I bought 2 quarts to get me back home and put in one quart, no leak. Put in the second quart, and it was leaking (pouring) out of the rear of the pan. I'm thinking that it was not leaking at the flat mating surface, but between the pan and the gasket at the u-channel.

I limped it back home and took off the pan. I cleaned it and the seal up, and this time put on sealant on both the mating surface and inside the u-channel of the gasket. I very carefully put the pan on and tighened each bolt to 5 ft-lbs in a star pattern.

I left the car as is and took the 2.6 to work. I'll let the sealants cure and fill it up with fluid when I get home later.

MVK · #17 07-30-2002, 06:07 PM

I have never seen anyone having to go thru this hell to get the tranny seal replaced. I still think you do not need the sealent if you have the pan and tranny body in perfect shape. Also make sure that the surfaces on which gasket is mounted are absolutely oilfree and dry. This way there will be no slippage of gasket upon tightening. Feel bad for you and hope things work out this time.

MVK

leathermang · #18 07-30-2002, 08:23 PM

What sealant did you use ?
Did you let it cure overnight before you put in the fluid ?

Mine was the first post after you asked for help, and while so many of these guys are talking philosophy of not needing a sealant, or that they did not need one , you never answered the questions which I asked in that first post... Greg

mplafleur · #19 07-31-2002, 01:55 PM

The sealant I used was Permatex high temp silicone. I let the sealant cure for 12 hours (during a 90 degree day) before adding fluid last night. I ran the car for a couple of miles and when I got home, no leak.

This moring I left for work and checked the pan for leaks a couple of times. After I had gone 3 miles, it was leaking from the rear!

Now I had scrubbed the pan clean in soap and water, also the seal and cleaned the surface of the transmission before seating the pan.

It must develop the leak under pressure. Could the new seal be slightly thinner than the OEM that a tight seal cannot be made when the bolts are torqued down?

I'm willing to try one more time with form-a-gasketbefore taking it to a shop. I just hate buying more fluid each time I try.

MVK · #20 07-31-2002, 05:51 PM

Sorry I give up too. I think you have some other problem leading to too much pressure building in pan. I would at this point givbe one last try and then take it to a good mechanic.

MVK

psfred · #21 07-31-2002, 09:50 PM

Michael:

Did you do the bang the pan down until it thumps solid thing (as is required for the valve cover gasket)? If not, clean all the sealant off and try again, this time thump the pan until the gakset is completely seated on the flange of the pan.

You may have not seated the gasket before tightening it, and when the pan and tranny heat up, the gasket isn't being held down properly, or it has slipped out of position since it wasn't seated.

I cannot think of anything else except that the gasket isn't thick enough and the pan isn't being held up tightly enough as a result.

Another thought -- are the bolts and holes completely clean? I assume so, but have learned while troubleshooting not overlook the obvious -- if they are getting tight before the gasket is compressed, it will leak when hot.

The only other thing I can think of is that the filter is preventing the pan from pulling up, but I'm sure you would notice that. I don't think you can get the filter in wrong, anyway.

Good luck, I hate simple things that go wrong.....!

Peter

leathermang · #22 07-31-2002, 11:41 PM

NEVER GIVE UP. I once took apart a chainsaw carb and put it back together 17 times in a row. Took me two days.... It is just a machine and it is just physics...... Don't let it whip you ....
I personally would not use silicone with a rubber gasket... some of them stick together and some don't.....
Next time.. why don't you try my suggestions.. along with Billrok's... run a tap into all those holes to be sure they are letting you get the correct torque... then clean everything.. put 3m super trim adhesive (yellow death is its nickname) according to directions ...on the pan and the lower side of the gasket... let them tack.. then put them together.... then use the aviation gasket cement on the top side of the gasket and the bottom of the trans..... I guess you know to put a layer on each clean surface you want to stick together... ?..then leave it 24 hours before putting the fluid in .. ( since you are having troubles with this particular pan )
Hang in there....

mplafleur · #23 08-01-2002, 09:40 AM

Thanks for all the great input, but I'm running up against the clock. I have to finish putting up a fence in the back yard for the dogs before we go camping next week. I've got two days to finish it and I've got 20 more panels and a gate to put up.

I think the problem is the gasket is too thin. Too bad I threw out the old one. It shouldn't take all these gyrations to get this to work.

FYI: I bought the filter and gasket from Fastlane.

There is an MB dealer a few mile away from our new house. I'm thinking of taking it in there and having them put the pan on. It can be ready for me when I get back a week later.

I REALLY, REALLY HATE to give. My wife too, was amazed that I was looking at have someone else do this. I never have (pay) anyone to do something for me that I can do myself. He!!, I'm even going to build my own plane! (and I'm going to put an oil-burner in it!)