[6pack] Transmission internal pressure question

[Mark Hooper]

Here is a new one for me:

Is a TR6 j-type tranmission supposed to have venting, or internal pressure?

I have a newly re-built j-type overdrive transmission on my 72 TR6. During
last season, I noticed that I had leaking oil dripping on the exhaust pipe
under the overdrive. I had thought it was a valve cover leak, but apparently
not. I have the cover off the transmission to deal with a u-joint replacement
(as well as nasty attack of Shipwright's Disease). So I took the car out for a
spin. Enjoyed the clouds of smoke from the POR burning off the header
extension pipe and then headed back home. I see now that the transmission is
weeping oil from the seals around the shifting rods which is then dribbling
down the side of the transmission and dripping on the pipe. It's not pouring,
but last year I was getting puddles under the car. I took a closer look after
the run and  I also see a oil bubbling from one of the gear detector switches
on top of the transmission case. To my mind bubbling = pressure. I don't think
just internal splashing would put out the amount of oil I have seen leaking
down the side of the unit.

I think the fellow who rebuilt the transmission and put in the nice unit from
Laycock Rebuilders used 80w90 gear oil. This I have been told is a no-no. I
have consequently refilled the unit with Valvoline 20w50 racing motor oil. If
it stops raining I will give it a run again and see if the problem is gone.

Is there a vent hole in the transmission somewhere that might be blocked up? I
don't recall on on the TR6 unit, but then I know the A-type better than the
J.

Certainly I used to use 20w50 in the a-type and did not have this leaking.
(Also had no overdrive due to slipping.)

Mark Hooper
1972 TR6