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Got me a 92 190e 2.6, when i got it the transmission pan gasket had a leak, PO had informed me. No big deal... or so I thought. So I ordered a gasket, did my research and went to work. Upon removing the pan i found one of the bolt holes (rear, right) was stripped and wasnt holding much. Luckily i could put a nut on the top side as the hole went through. I drained, cleaned up things replaced the torn gasket. Not having a light spec torque wrench, i used a nut driver to make sure i couldnt get too carried away. Darn thing waa leaking all over the floor by the time i was done adding fluid. Further diagnosis lead me to believe the pan was warped... So bought a pan and another gasket, and a cheapish torque wrench. Still leaked! Not as bad, but indeed leaking, not from the area of the stripped bolt however, but at the front of the passenger side. So I tried again... closer inspection showed the gasket ever so slightly was being pushed to the outside and not flush with the transmission like the other sides. I tried again, being really careful the gasket was seated properly, and it still kinda flubbed out a touch causing some leaking, so i tried again! Using less torque, just snugging the rubber against the transmission, and keeping an close eye on the tabs making sure they werent being crushed, but just touching the edge of the transmission, the leak slowed up and still persists. Im at a loss, i would have never thought such a simple task could cause so much trouble. Im sure the filter is in proper, ive made sure surfaces are clean, ive made certain not to over torque, im fairly certain the leak isnt from the dipstick, ive run out of ideas! I feel really just stupid and am leery as to what if any help a shop around here might be and the shame of having a stripped hole and looking like the dimwit that did it... (yes, i will likely put a helicoil in...) between this and ignition tumbler issues , the car has been quite an experience in the less than 300km i have been fortunate to drive it...

What am i overlooking here? I feel embaressed even asking after this many attempts lol.

Thanks
 

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89 190E 2.6 x2
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1,492 Posts
I've serviced the transmission a number of times, so here are some tips from me.
Those bolt holes do strip out very easily, so definitely re-thread it.
Torque is crucial, I think it's like 7 ft lbs.
Get the gasket warmed up so it's more pliable, then put it on the pan. Once I've done this, I push the pan up in one swift motion and get it seated. The most common pinch point w/ the gasket seems to be by the electrical connector. Once I've got it in place, I usually torque it criss cross.
It does take a lot of practice though! The first time I did it, it took me 4 attempts to get it properly seated.

Do check your dipstick as well and make sure it's not loose. Years ago when I used to pay a shop, they serviced the transmission and then it leaked. Took it back and the dipstick was leaking so they tightened the fixing bolt.
 

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1985 190D 2.2 1992 190E 2.3 1993 190E 2.3
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I agree its a good idea to warm the gasket and keep it pliable and relaxed. Also, clean the pan thoruoghly. After thorough degreasing, wash it with detergent (I like warm water), rinse well and either air dry or use microfiber, compressed air or any means that won't leave lint or fibers behind. A dry clean surface will "grab" the gasket. I also agree you want to lift the pan with gasket in place carefuly, then get a couple bolts in place in the middle of both sides. Just turn them by hand enough to keep the pan level. It doesn't have to be pulled up in contact, yet. Then, begin adding a bolt at alternating ends, finally adding the remaining bolts. Then turn them each a little at a time, and pull the pan up evenly. I know. It sounds tedious. It's really not. It helps keeps the gasket in place. When you think you have the gasket in contact with the transmission surface, (before torqueing) get a flashlight and inspect all around the top of the pan against the transmission. You should see the gasket edge evenly all around. You'll have to get up close and personal with your flashlight. It's tight in some places like the corners on the front. You can run your finger along where you can't see the edge to make sure its seated. Take your time. Any doubts, loosen the bolts, and reset the gasket. Please don't try any gasket cements. The next service will be a nightmare trying to get the pan off. And please use a torque wrench. I don't go for full torque on the first pass. I snug them up just making sure I have contact all around (again, pull it up evenly). When I'm sure its good to go, I torque at roughly half or two-thirds before final value. One last thing. Not all brand of gaskets are equal. I struggled a little more with Elring than with Mercedes original, and I threw away a Uro brand gasket. Worst of any I've tried. Febi was ok. Something to consider. A few extra dollars could be well spent. Good Luck!
 

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89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
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I do not have an auto transmission but I'm guessing that you want "all" the bolts and screw holes "dry" so that the torque can be correctly set. If it is 7 ft-lbs there will be a huge difference in the upward force between dry and wet bolts.
 

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1985 190D 2.2 1992 190E 2.3 1993 190E 2.3
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I do not have an auto transmission but I'm guessing that you want "all" the bolts and screw holes "dry" so that the torque can be correctly set. If it is 7 ft-lbs there will be a huge difference in the upward force between dry and wet bolts.
Applied torque on a bolt causes the bolt to stretch resulting in "clamp force". For the 722.4 transmission pan, specific bolt specs are selected to supply adequate clamp force using the specified torque. No preference for "wet or dry" is called out because the large surface of the somewhat thick synthetic gasket requires low force to supply an adequate seal, hence the modest 7ft-lbs torque spec (edit - just recalled its a little less ~6ft-lbs) with resulting low clamp force.

Depending on the bolts' condition, a quick wash in parts cleaner, maybe a blast of air or a simple wipe will do. Both gasket surfaces are expected to be cleaned and usually a quick shot of air in the tapped bolt holes is adequate. The only time I've seen anyone strip a 722.4 transmission's bolt hole, is when a torque wrench was not used by someone with little to no experience. Inexperience seems to expect the bolts should be much tighter, until that moment when they feel the thread give up.

It's true that lubricating a bolt will result in greater clamp force for a given torque, in general. In this case, any residual fluid isn't an issue.
 
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