Leaking Transmission

I've mentioned in a few places that I had my T86 Transmission rebuilt using T90 parts placed back in the T86 case. I thought I had a leak in the transmission, out the front leaking down and thru the bell housing, out the rubber boot where the Clutch fork links up with the linkage to the clutch pedal etc. It didn't seem to make sense, for the transmission to leak out the front, it would have to fill up the 2" wide adaptor and spill over the front edge of that, (V6 adaptor to tranny). It did make sense that it would be leaking though, because the transmission shop admitted that they did not install the Front Bearing washer. So, we pulled the transmission back out and the adaptor was completely dry, the front of the transmission case was dry - didn't make sense. Then we noticed what looked like oil coming from the backside of the motor, not visisble normally, but visible with the transmission out and the bell housing pulled, (I replaced the clutch while we were in there), so maybe that explained it, but given the quantity of oil, and the fact that the motor oil level hasn't moved a bit on the dipstick, I don't think that's it.
The more I think about it, the more I think it is gear oil from the transmission. Given that the main drive gear shaft extends out of the transmission, maybe 8 ", wouldn't it make sense that it would leak out of the splined end out beyond the adaptor, and be able to leak directly down into the bottom of the bell housing and splatter all over eveything below? Or without the front bearing washer, would it leak directly out of the front of the transmission case? Had a leak around the speedomoter cable where it screws into the side of the case as well, thought I had that taken care of with Teflon tape, but it's still leaking a little as well, any ideas? Replace the cable and connector? Sorry for the long thread here...

 

Smell your oil leak. See if it smells like gear oil (which should also be thicker), or motor oil.

 

I'm pretty sure it's gear oil. It's coming through very clean, and the transmission was just rebuilt/refilled. I drove for an hour or so today, parked and looked underneath, and it wasn't even a dripping, it was a steady stream making a puddle on the floor about 10" in diameter in ten minutes, then stopped.

 

The oil level in the tranny was also down, while the engine oil on the dipstick hasn't budged.

 

I found why mine was leaking from the transfer last week. It appears that when you fill the trans, you end up overfilling the tranny due to the open bearing and the breather holes.

 

It sounds to me like you found your leak.

 

I've been thinking I was possibly overfilling mine. Someone told me the exact amount necessary to fill both the transmission and the transfer case is 3 pints. Is this correct? And where do you fill, I have been filling both from the same location - the fill plug/check level plug up high on the drivers side of the transmission right next to the two "bumps" on the transmission. Id this the right way to do it?

 

What transfer case do you have?

 

T18 I think. Single stick, 3 speed, non synchronized 1st, reverse up and top the left.

 

If it's a Dana 18, There is a fill plug on the passenger side near the rear of the t-case. I don't know how many pints it'll take, just fill until it runs out at you.

 

I've seen that one, but it doesn't seem high enough to get much oil up into the transmission. But if that's the proper procedure, then I've probably be overfilling mine in a big way. If that's the case, what's the fill plug for that I have been using? (The one on the drivers side beside the two "bumps" on the transmission)

 

There is one for the tranny and the tcase, at least there was on the T90-D18 combo I had in speedy.

 

Sorry, I want to make sure I get this right. I should fill both from the same fill plug on the passenger side of the transfer case, or are their two plugs to fill from, and if so, where are they? Mine is a Dana 18 transfer case and a T86 transmision. Actually it's a T86 case with T90 parts inside, just rebuilt. Thanks for your help on this!

 

Fill the tranny using the fill plug on the drivers side about 1/2 the way up. Fill the dana 18 on the passenger side using the fill plug you already mentioned. Fill both to the fill plug level.

 

Sorry for beating this subject to death, but if you only fill from the transmission side, will it fill the transfer case? My problem is a leak showing up at the front of the tranny leaking out the bottom of the bell housing. The guy who rebuilt the tranny left off a part, the main bearing washer, which he swears isn't needed because my T86 case was machined for a rubber seal at the inside of the output shaft. When we pulled it apart, the adaptor was dry, the clutch was dry??? Can't figure it out. So, I was thinking maybe I overfilled it. I can drive it for 15 minutes and no leaks, but run it down the road for a hour or so and it leaks bad. THe guy at the transmission shop said the entire transmission and transfer case should hold 3 pints, is this correct?

 

It will slowly fill the transfer case, but both will be low then. I would fill both, independently, to make sure the t-case is not running dry. It will always leak, it's just a matter of how much.

As for the 3 pints....no idea, but that doesn't sound like enough. If both are filled to fill-plug level, then they each have enough

 

trans = 2.5 pts
transfer case = 3.25 pts

I wonder if your oil leak is a missing shift rail plug up top on the trans shift tower

 

I had the floor boards off and nothing showed. It's a real mystery. I pulled several bolts out of the bell housing dust guard tonight and peaked up in there. The flywheel looked dry, but the bottom inside of the bell housing is wet with gear oil.