Tranny Help

[76bonanza]

Had a leaky transmission thought it was the pan replaced it with a cast alum pan from summit. I am pretty certian it is not leaking. But alas I have some leakage looks like it is coming from the passanger side not from the lines lower than that but just above pan. Maybe from the dipstick sleave?????

I have a th350.

Any help would be helpful small leak one or two drips a trip maybe a quart every six months or so.

[Frank-id]

Auto trans leaks for GM vehicles is easy to spot but sometimes hard to repair. The most common trans leak would be the extension housing seal. The driveline front yoke slips into seal. Rear bushing becomes worn and seal leaks. Next would be the front pump seal. Trans must be remover to replace seal. Just old makes this seal leak as seal becomes brittle. The next seal that fails is the "o" ring at the bottom of the trans dip stick tube. Easy fix and cheap... some times the govenor cover will seep a little and, the shift lever shaft can leak a little, and the pan gasket. This gasket usually just needs to have the fasteners snugged up a little tighter. Time, heat, milage and abuse can wear out or destroy any seal. Most seals are equal in quality. Tricky oil pans are just for ego and looks. There are a few add ons that are of value to the longivity of a trans. The most important trans saver is a good large trans external cooler not connected to cooling system. This cooler can be cooled by fan or forward motion. Also a great trans saver is an external spin off oil filter and the use of synthetic trans fluid. Standard trans fluid can be cooked in 25 miles but synthetic cannot be cooked. Very bright shinney ATF is good as dark red or brown is NOT good. Black fluid must be flushed several times...

[Sweet72]

Probably the dipstick tube O-ring or lip seal depending on which type your TH350 has. Worst case scenario, a crack or case porosity leak.

[76bonanza]

From looking at it looks like it might be the dip stick seal or shift lever. What is the govener? Also any step by step ins on how to change dip stick seal or shift lever seal?

[Sweet72]

If the leak is clearly coming from the right side, it wouldn't be the shifter seal or governor cover. It may also be the 1-2 shift accumulator cover O-ring.
To change the dipstick O-ring. clean surface around dipstick tube with solvent and rag so no dirt can fall in when tube is removed. Dipstick tube is held in place by one of the tran. to engine mounting bolts. Remove this bolt and any clamps that are holding the dipstick tube to the vacuum line which runs parallel to it. Pull dipstick tube out of case just far enough to remove O-ring or seal and replace with new one. Be sure to lube the new O-ring with petroleum jelly or clean trans fluid, dont use grease. Reinstall and leak check.
-Sam

[Sweet72]

Forgot about the bolt that holds the tube to the case, at the base of the tube.
-Sam,

[Mike76251]

Originally posted by Frank-id
Auto trans leaks for GM vehicles is easy to spot but sometimes hard to repair. The most common trans leak would be the extension housing seal. The driveline front yoke slips into seal. Rear bushing becomes worn and seal leaks. Next would be the front pump seal. Trans must be remover to replace seal. Just old makes this seal leak as seal becomes brittle. The next seal that fails is the "o" ring at the bottom of the trans dip stick tube. Easy fix and cheap... some times the govenor cover will seep a little and, the shift lever shaft can leak a little, and the pan gasket. This gasket usually just needs to have the fasteners snugged up a little tighter. Time, heat, milage and abuse can wear out or destroy any seal. Most seals are equal in quality. Tricky oil pans are just for ego and looks. There are a few add ons that are of value to the longivity of a trans. The most important trans saver is a good large trans external cooler not connected to cooling system. This cooler can be cooled by fan or forward motion. Also a great trans saver is an external spin off oil filter and the use of synthetic trans fluid. Standard trans fluid can be cooked in 25 miles but synthetic cannot be cooked. Very bright shinney ATF is good as dark red or brown is NOT good. Black fluid must be flushed several times...

This needs to go in the reference section...........much good info here!!

[76bonanza]

It is defenatly coming from the dipstick side what is the 1-2 shift acumulator o ring and how hard is it to change? If I get a chrome dipstick sleave (I have been wanting one anyway) will it have a new oring on it?

Thanks

[maineiac]

Sorry to hijack your thread but I have a simular problem with my new tranny but mine only leaks when it is under preasure (ie going down the road ) it will sit an didle all day with out a drop spilled can even put it in gear and roll it back and forth no problem but drive it and you get a small puddle each time. All appears to be comming from the right side. It is a nonlockup tranny.

Thanks in advance
Steve

[Frank-id]

My long distant guess would be..
A bad cooler line or fitting. There is little or no fluid pressure while idleing. The cooler lines get pressure as trans is put into gear. Place newspaper under trans and look for leaks.