Looking For "Truck Church" On Tranny (Transmission)

[chopped68]

the turbo 350 with converter will be about 10 quarts with the stock pan,deep aluminum pan 12 quarts.if it is overfilled,it is coming out of the vent in in the top of the case.also check the dipstick tube rubber grommet and the orings on the vacuum modulator(it is at the passenger side rear just above the pan).1 thing you could do for your t350 is get a low first gear kit.it is a 2.75-1 first gear so you could run a taller axle ratio.

[magwakeenercew2jh]

Originally Posted by chopped68

the turbo 350 with converter will be about 10 quarts with the stock pan,deep aluminum pan 12 quarts.if it is overfilled,it is coming out of the vent in in the top of the case.also check the dipstick tube rubber grommet and the orings on the vacuum modulator(it is at the passenger side rear just above the pan).1 thing you could do for your t350 is get a low first gear kit.it is a 2.75-1 first gear so you could run a taller axle ratio.

Thanks much for all of that. Where's the vent in the top of the case?

[chopped68]

the vent is on top above the transmission cooler fittings.

[BruthaMan]

I feel for you, am kind of going through the same thing. Trying to get the truck to a point where I don't have to put a maxipad down on the driveway every time I park the truck.

Transmission is finally sealed up. Did basically what you did, took the pan out, cleaned everything down, replaced filter, put on a new "top of the line" gasket (used gasket sealer), then replaced the seal on the shift link. Added in some Lucas transmission "conditioner" that has sealer as well. So far, not leaking.

Motor (GM crate with about 12k miles) had a small leak from front seal. Last oil change (mobil 1), added some motor leak stuff. So far, doing good.

Went out the other day and there was a big leak under the truck and about had heart failure. I knew it wasn't trans because of the clear color. Started checking around motor and oil pan, but nothing. Started thinking maybe someone came along and just dumped a cup of oil under my truck to mess with me!

Then as I was sliding out from front, I saw some moisture. It was the power steering box. I had loosened it and moved it when replacing belts last weekend. The hose going into the pump looks old and cracked. I tightened it down some, but plan to replace it when I have some free time.

Have you tried any transmission leak products? The Lucas product worked pretty well for me. Maybe it would be enough to stop the leaking for a while, and provide the opportunity to save up for the new transmission.

[SS Tim]

The trick I was taught years ago is if you don't know how much or if you suspected an overfill was to loosen the pan bolts with the vehicle running and hot, let it drain. When it stops it should be real close to the normal running fill level. Tighten everything up and clean. Also TH350 did have case porosity problems, how old is it? The dealers used to epoxy the outside of the cases. Had a bulletin at one time but.... its somewhere 'round here.
Now do you have a really big external cooler that might be draining back causing enough of an overfill to come out of the vent? You can always try a check valve in the cooler supply line or lowering the cooler.

[LockDoc]

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If fluid is coming out of the fill tube hole in the case it has to be over full. If you can't trust your dipstick reading do what Tim suggested to get you in the ballpark. The only thing I'm not sure about is having it running when you do it. I can understand having it hot so the fluid is expanded. I am by no means an ATM guru, so I don't know.

If you decide to go with a 700r4 the 3.07 rear gear will be to high. It can cause the trans to overheat when it is in overdrive and blow fluid out of the front seal, and your mileage will actually go down. I just went through this with the Suburban... I'm changing over to a 3.73 rear gear in it.

LockDoc

[SS Tim]

Originally Posted by LockDoc

-...do what Tim suggested to get you in the ballpark. The only thing I'm not sure about is having it running when you do it. I can understand having it hot so the fluid is expanded...
LockDoc

The reason you have it hot and running is that trans fluid expands and that raises the fluid level over cold. The other is that an automatic transmission has a fair amount of fluid in action when the trans is spinning. The valve and lubrication passages, clutch packs and the torque converter all take from the pan during operation and drain back when the engine is off. Next time you are checking trans. fluid look at it cold engine off first then start it and run it there will be a noticable drop in level even with the fluid expansion.