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What happened to my m46 overdrive sump??

DavePolyakov

Member
Joined
Aug 3, 2020
Location
Shoreline, WA
Went to change the fluid in my m46, noticed the sump surface is full of scratches and there are even two small cracks in the bolt holes. Would adding silicone then installing the gasket be my best bet? What can I do? Need this to be fixed in two days.
IMG-2733.jpg

IMG-2734.jpg
 
I'll bet someone over torqued it, warped it and then tried to true it up with sandpaper on a flat surface.
Make sure the surface is flat and do a better job sanding down the surface if not.
I don't use sealer on cork gaskets, but if that has a paper gasket, a light smear of RTV would probably be ok.
There's no pressure there, but it is submerged.
And don't over torque it when you put it back together.
 
Looks like it was over-torqued.
You can probably get away with replacing it with a fresh gasket for now, but it will most likely leak at some point, which will damage the OD if left unnoticed.
I'd replace the cover.
 
Only a little more than a quart of oil came out...

The drain plug.

IMG-2732.jpg

Looks like it was over-torqued.
You can probably get away with replacing it with a fresh gasket for now, but it will most likely leak at some point, which will damage the OD if left unnoticed.
I'd replace the cover.
 
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Sump cover mating surface was gouged from previous clumsy attempt to scrape off the gasket.

Crack around bolt hole from over-tightening the bolt. The torque spec is pretty low for those.

Only a little more than a quart of oil came out...

The drain plug.

IMG-2732.jpg

From both the tranny drain plug and OD sump? Little over a quart total does seem low. :oogle:

Some good sized shavings on the magnetic plug there. How long since the last fluid change?
 
The fluid was quite red. Even driving today with all new fluid, it's extremely hard to shift. It's gotten worse. I don't know if I need new bushings or what, but its hard to shift into all gears, 3-4 are easier. From a stop shifting into 1st is the worst.
 
Probably time to replace the clutch and be sure to replace the pilot bearing. They wear and make it very hard to shift into first and reverse.
 
The clutch also grabs right off the floor. Like right off the floor. Probably should adjust it a little looser? I can inspect clutch and pilot bearing, I have a transmission jack.
Probably time to replace the clutch and be sure to replace the pilot bearing. They wear and make it very hard to shift into first and reverse.
 
To make the clutch pedal grab a bit higher. You tighten the cable adjustment. For lower to the floor it is looser. My 93 wagon has the grab point very low and I have to keep the cable adjusted a bit tighter than stock adjustment to keep the grab point from being too low.
 
Granite Surface Plate is the best, but probably overkill in this instance.

I use a piece of thick glass from an old glasstop coffeetable. In this case, any reasonably flat sturdy surface will do.

What did the sump cover's mating surface on the bottom of the OD unit look like?

Scratches on the mating surface that traverse from one side to the other are easy avenues for fluid migration.
 
The bottom of the OD was fine. I'm at school right now. I think the m46 is leaking from multiple places. I'd be fine setting aside some time to replace some seals but I don't want to spend too much time and I don't want to disassemble much of it. I don't exactly know if it's leaking because all the leaks end up dripping off of this sump anyways. However, when I drove to school overdrive engaged much quicker than it used to so the increased fluid level definitely helped. If it starts to engage slower then I'll know it's leaking.
 
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