a-904. Still leaking after rebuild! :(

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Corrupt_Reverend

Corrupt_Reverend

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Finally got everything buttoned up. Got the shifter in, trans filled, and back on the road.

But now I've got a leak at the front of the trans. It's coming from behind the dust shield.

Every bushing, seal, and gasket got replaced when I rebuilt. Got a brand-new TC, everything should be ship-shape.

Anyone know what I could have missed? I'm real tempted to try some of that "stop-leak" stuff, but it bugs me that I'm even considering that when I've got maybe 2 miles on the tranny. (That stuff makes me nervous anyway.)

Any ideas? I really reallly don't want to have to pull the transmission again. And even if I did pull it, what could I even do? Everything that's replaceable has been replaced. This is drivin' me batty.
 
did you flush the cooler lines?
Is the trans showing full in neutral, warmed up.

Start the motor, put it in neutral, parking brake on, and look underneath, is it dripping while running
 
Well, it leaked overnight so it definitely leaks while not running. It drips while idling in neutral, but I don't know if it's actively leaking then, or if that's residual from just leaking in general. I would think that if it leaks while not running, it would also leak while running, right? (I don't think it's an over-full issue leaking when the pump drains or whatnot because in the morning, the fluid is low)
 
Does it move?Did the sealing washers go under the pump bolt heads?Oh wait, thats GMs.
It really doesnt much matter. Its got to come out. Then it may be obvious.
Wait. Whats that mean; still leaking?
 
Replaced all the washers on the pump bolts.

One of the motivating factors for the rebuild was the massive puddle under my car. Needed a rebuild anyway.

I just ran to the store, and there wasn't a new puddle under the car. Maybe I overfilled a little? Would that cause it to leak at the front? (If it was overfilled, it wouldn't have been by much.)
 
The vent is in the bellhouse ,at the top of the pumphouse.If you overfill it at first start, all the rotating parts inside which are now swimming in oil, fling the oil everywhere . Some can find its way to the vent.When the TC fills up the level stabilizes. If its still too high, it will continue to vent it until the level is below the rotating parts.I have accidentally overfilled my 904s from time to time. A half liter,oops quart, seems to be accepted without venting.
 
the sealing washers on the pump bolts, were they metal or fiber?
Did you check the fluid level to see if it was overfull.
If it drips while running, in nuetral, the pump seal could be an issue, but a restricted cooler flow can also cause it to push out past the seal. its going to go somewhere if the cooler flow is restricted.

Do you have aftermarket trans cooler, or just into the rad?
 
I just kept the rad cooler. Was thinking about upgrading to an external cooler though.

And now that I think about it, I didn't flush it. I was going to, but got a bit carried away trying to get the car back on the road, I forgot to.
 
Now I'm really thinking it might be the cooler when I think about it. I did a MVB as well so I've got the throttle pressure lever wired all the way back. Maybe the combination of the higher pressure with restrictive cooler is causing the leak?

Or maybe it's just wishful thinking in hopes that I won't need to drop the trans again...
 
There is a possibility of knocking the spring off the inside of the pump seal also, just so you know to watch for it.
The spring will ride around the converter snout until the converter comes out again, then it can drop into the pump.
I used to put a little assembly lube in the back of the seal before it went in to keep the spring in place while the seal got tapped in.

The seal can also pop out after it'a all back in the car also, and they have a spring steel retainer for that if needed. (red locktite on the seal always worked for me)

But if it doesn't leak anymore it was probably just overfilled, or foamed and overflowed on startup as already mentioned.
 
Did you check the plug screw in the bellhousing for the kickdown lever pin? could be there but not tightened / sealed.....

Michael
 
Since you dont know what it is, you didnt mess with it. That doesnt mean its not in there or loose.
The kickdown band is anchored on its ends. One end to the adjuster. The other to the apply lever. The apply lever pivots on a steel pin which is installed from inside the bell house. After it goes in, a small plug is screwed in behind it to seal the access port. It is on the drivers side, at the bottom. About 5 oclock as viewed from in the bellhouse.
 
Ah, I know what you're talking about. The plug that you remove to be able to pull the front band lever rod. I left that in place when I rebuilt because I was able to flip the lever over to remove the piston (to replace the seals).

I just got back from work. When I went out to my car after work, there was a small puddle so it is still leaking. I'll go out and check the fluid level after I get something in my belly.
 
Aftermarket converter? Higher stall?
I had the same problem and my external oil cooler was too small. It was puking out of the vent hole when it was getting hot. Installed the largest trans cooler the parts store had and never had another problem. I would look there too.
 
I installed an upgraded converter built by Pat Blais. The stall is around about 2300. So an upgraded cooler might solve the problem?
 
Cr, I had a 727 I pulled 7 times. Guess what ended up being the issue? Pinhole in converter and it spun fluid out that drained out of bell housing when car was in my garage. That sucked. But I got good at pulling it.
Tom
 
Came back to town after the weekend. Greeted by a substantial puddle. :(

I have a cooler on the way, but I'm beginning to think the stock cooler being restrictive isn't the cause of my leak.

Starting to feel like pulling the trans back out is unavoidable. Just typing that hurts a little...
 
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