transmission pan woes or the SPOT that won't go away.

[JHogan]

When I got this car I was slack in doing the things you do when you acquire a car such as oil change,
valve adjustment and transmission fluid and filter.
I haven’t driven it much and I finally got around to
doing the transmission fluid and filter.

I did drain the torque converter the first time and put in a new filter,
no sweat.
The tabs on the pan look a little tweaked but
I didn’t give it much thought. New M/B factory gasket.
Cleaned mating surfaces up with carb cleaner, no goop,
recommended torque is 7.5 ft/lbs? OK, my wrench doesn’t go that
low so I use the 'grab the head of the wrench technique',
not my first rodeo, good? Good.


Oh, no. It’s still leaking from the pan to tranny mating surface. Damn.


OK, throw a hunk of cardboard under it and let it slide.
A couple months. ( I got things to do, shut up)

Back under the car, drain the pan, no torque converter, take the pan off, bang on the “feet” to get them square
under the pan so as not to over tighten.

One more time. Cleaned tranny surface, looked for imperfections.
Cleaned gasket with Dawn and a soft brush. pretty, clean.
Shiny good. Still skimping on the torque wrench.
This time I cheated and smeared a very thin, (no thinner) layer of black sealer onto the gasket.

I am proud of my work. I am KING. For about 9 hours
until the next morning.


The dreaded SPOT ON THE CLEAN CONCRETE.


I hate the spot. I’m not real thrilled with the
hunk of cardboard on the $7K driveway
either. Damn.


So, One more time. Going to get the
inch pound torque wrench,do it right.
Bought another gasket.

My hypothesis is I’m over tightening the gasket,
or, OR, the “feet” are tweaked.

Am I missing something?

Constructive criticism welcome.


JHogan

[running-snail]

Sounds like a similar experience when I first bought our 123. I ended up ordering a new trans. pan. Took care of the pan-to-trans leak.

(Now I've got a front seal leak that is getting progressively worse.)

btw - Nice looking TD!

[SD Blue]

Where, in reference to the pan, are you seeing the leak? Another possibility is a pin-hole leak in the hard cooler line and the fluid migrates back along the line and drips. The rubber that cushions the clamps for the cooler lines deteriates and eventually the result is metal-to-metal and vibration wears the wall of the tubing.

Using a piece of glass helps to find high/low spots on the mating surface of the pan. Remove the gasket and apply a little transmission fluid along the mating surface and laying a piece of glass on it tells the tale.

[toomany MBZ]

Originally Posted by SD Blue

Using a piece of glass helps to find high/low spots on the mating surface of the pan. Remove the gasket and apply a little transmission fluid along the mating surface and laying a piece of glass on it tells the tale.

This a good way to check the pan for flatness.
Yes, over torquing can lead to a spot. I had a leak on my SD, I did a service, used a new gasket, torqued to 7 Nm or 5.2 Ft. lbs. I made sure the mating surface was clean, just wiped it dry. Problem solved.
(Nice car!)

[Matt L]

When you get the edge of the pan flat, put it back with another new gasket.

[bgkast]

I'm having the same infuriating problem on the 560SL. When I got the car the transmission pan started leaking as soon as I pulled it into the driveway. I could actually see the fluid weeping past the gasket. I drained it and put in a new filter and gasket (the set I had been saving for my SD ). All was well for about 3 days, then I noticed a small puddle under the car. The small puddle has now grown to a huge pool.

Is the consensus that the pan is likely the problem in cases like this?

[JHogan]

The glass idea is good, although the 'feet' stick up a bit IIRC, but I've got a piece of plexi that I could cut to fit for the check. I also have another pan I could rob from the parts car, but it's in the weeds. Yay. Or I could continue ignoring it and buy a something bigger that comes it cardboard. Does a Mini Cooper S come in cardboard? Thanks for the suggestions and compliments on the car. I'll update the thread when I attempt a fix.

So, inch pound calculation for ft lbs, a hunk of custom plexi, a new gasket, check the coolant lines, and go climb in the weeds. This thread added up differently than I thought it would!

Jay

[toomany MBZ]

I don't know of a formula, but I do have this, see pic.

EDIT: Any flat surface will work to check the pan, just lay it tranny side down and try to rock it or check for openings.

[300D85]

Often, folks try to fix oil pan leaks by tightening screws/ bolts too tight (or past specs) & end up distorting the oil pan or bolt hole(s) area.

Then a fresh proper gasket & torquing of the bolts will not work.

Some folks use a ball peen hammer on a hard surface to flatten out the distorted (or no longer flat) area.

[JHogan]

I'm finding this car had very good maintenance from the original owner. I was sold to a jackleg whose favorite tool was a hammer. And now to me. I'm finding a lot of things done very well and a few things done very shoddy. All the records are still with the car until about two years before i got it. Using the expired inspection sticker on the car for reference the jackleg mech only had the car running for about 9 months and a clogged fuel filter took the car off the road. I found it on a used car lot in the back, hidden, as a non-running trade-in. Thanks for the illustration on NM to FT/lb.

Jay

[toomany MBZ]

Originally Posted by JHogan

I'm finding this car had very good maintenance from the original owner. I was sold to a jackleg whose favorite tool was a hammer. And now to me. I'm finding a lot of things done very well and a few things done very shoddy. All the records are still with the car until about two years before i got it. Using the expired inspection sticker on the car for reference the jackleg mech only had the car running for about 9 months and a clogged fuel filter took the car off the road. I found it on a used car lot in the back, hidden, as a non-running trade-in. Thanks for the illustration on NM to FT/lb.

Jay

No prob, and good for you!

[mobetta]

another possible leaker is the tranny moduLATOR ORING. I HAD ONE LET GO AND IT SEemed to be a pan gasket, but upon closer inspection, it was the oring. it leaked like a sieve while running, then dripped while parked.