HELP With a Transmission leak!

[Robert Lindberg]

First: Thanks Mike for getting me back on this Forum!!!!!!!!!!!!!!

I've been fighting a transmission leak for 1+ years in my 1966 toronado. I replaced the lower

pan gasket 3x last time doubling the gasket. The rear pan around the chain 2x I had to cut the

top of the gasket to get it in. I've heard a small leak is normal do other people have the same problem?

101,500 miles on the engine. How can i find out which pan is leaking. I've had up on a lift for days, and just

jacked up but can't find out where it's coming from. Can the rear transmission pan be removed without

pulling the engine? Thanks in advanced! Bob

[bcroe]

I've been fighting a transmission leak for 1+ years
in my 1966 toronado. I replaced the lower pan gasket 3x last time doubling
the gasket. The rear pan around the chain 2x I had to cut the top of the gasket
to get it in. I've heard a small leak is normal do other people have the same problem?

101,500 miles on the engine. How can i find out which pan is leaking. I've had
up on a lift for days, and just jacked up but can't find out where it's coming from.
Can the rear transmission pan be removed without pulling the engine? Bob

I wouldn't say any leak is "normal", but finding them & fixing them can be difficult.
You need to determine exactly where the leak is. I've had leaks at the shift shaft,
modulator, electrical connector, governor, pan, input/output shafts, and chain cover.
Some caused by wear, some by a failing seal, and some by rust. Fix one, and then
find the next one.

You might have luck by getting the trans completely cleaned; then drive a few
miles & park over a drip catcher. See where the oil comes down; maybe see the
first wet spot on the trans. Found one that way this month on a TH400. The
plastic gear driving the speedo had so many miles, it had worn and left a gap
at the seal. I added another seal next to it where the shaft wasn't worn, and
put a new O ring on the gear support, cured.

In another case the shift shaft had rusted enough to cause a rough surface,
and the seal didn't really work anymore. Best fix is a new shaft. Maybe
braze it and turn it back down would work.

The chain cover is a poor gasket design. There is very little clamping surface at
the bottom, just where you need it most. Can't count on cork staying in place.
Some people (including me) glue them back on, like the 79 or so valve covers
with no other gasket. good luck, Bruce Roe