Transmission IBS on a 94 c1500

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Jerryred94silvy

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Hello all,
I recently bought a 1994 RCLB silverado 1500 that has acquired a rather frustrating habit of leaving nice big ATF puddles on the ground. The first time it did this, I was about a mile from home when the engine light let me know that it still worked (good to know). So I drove it back home and found it dripping from the hole in the access panel, a steady drip, which we traced back to the torque converter seal. Replaced the seal, ran it around the block several times, everything seemed dandy. Until the second time...I arrived at the place to have it inspected, and discovered that transmission fluid is POURING out of what appears to be the front of the transmission pan(right behind the access panel). The kind gentleman who worked there noticed that it looked like the gasket had let go and was thus kindly sharing its special reserve of Super-Tech ATF with the asphalt. So a friend of mine came to help me and we changed the pan gasket and the filter (might as well) in the parking lot. Once we got it all back together we poured 4 quarts (instead of all 11 and THEN finding out if we didn't fix it) of the finest STP Dexron VI in the tube and started the truck to see if we had cured the transmission's bowel issue...... We did not. It leaked from the same location, where the pan and the access panel meet, and only began leaking when the truck was running. I'm sure the waterfall of ATF originates from somewhere further inside the transmission, but I need some advice from people who know more about these trucks than I do to help me figure this out before I take it to a trans shop and throw more money (and curse words) at it than is necessary. The truck has a 4l60 in it behind the mighty 4.3l V6, and is a 2WD. Thank you in advance for the help.

P.S. I am a noob, so if this thread is in the wrong place I apologize
 

Tony454

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I'm going with either the bushing for the torque converter is worn out and you ate up that seal again, or the front pump seal is bad.
 

Jerryred94silvy

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Is the bushing supposed to be on the input shaft where the torque converter sits? When I took off the TC there wasn't one there. I'll take the access panel off today and see if I can see exactly where it's leaking from.
 

Jerryred94silvy

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It looks like it is shooting fluid out from behind the torque converter, as in, from the backside of the TC towards the the front of the trans. Is it possible that I did not seat the TC properly? Or does that sound like something that would be caused by a bushing/seal that has died?
 

Schurkey

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Bushing for torque converter hub could be worn, or it could have slid forward blocking the return path. No converter seal will hold up to a displaced bushing.

Ford had common problems with that decades ago...but it can happen to any trans.
 

Tony454

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It looks like it is shooting fluid out from behind the torque converter, as in, from the backside of the TC towards the the front of the trans. Is it possible that I did not seat the TC properly? Or does that sound like something that would be caused by a bushing/seal that has died?

Well, the seal is definitely not doing it's job anymore. Hard to say without actually putting my hands on it. YOu either kicked the crap out of it putting the TC back in or something is causing it to fail again. Does the engine have a big oil leak too?
 

Jerryred94silvy

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The engine is not leaking oil(thank God), but the torque converter did fall off of the input shaft as we were reinstalling the transmission. It didn't fall far and didn't seem to cause any visible damage to the TC. And as for the seal, I don't recall doing anything to it that would have damaged it. We made sure it went in straight and was seated flush all the way around and put that little clip back on with no problems. And it didn't leak when I drove it around the block, it only started after about 8-12 minutes of driving. What would cause that seal to go bad so quickly?
 

Jerryred94silvy

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Bushing for torque converter hub could be worn, or it could have slid forward blocking the return path. No converter seal will hold up to a displaced bushing.

Ford had common problems with that decades ago...but it can happen to any trans.

Where would that bushing be located? I have the trans out now and it looks like the TC seal was fine but fluid seemed to be coming/leaking from just behind the TC seal. is that the front pump seal? or is this the fabled TC bushing of which you speak?
 

Schurkey

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Pop the seal out of the pump housing. You should see a fluid return hole right behind the seal area, and a bushing just behind the hole.

The fluid that lubes the bushing has to have somewhere to go. It's supposed to drain out behind the seal, in front of the bushing.

If the bushing wears, there's more fluid leakage out the bushing than the drain hole can flow. So the seal leaks.

If the bushing slides forward in the pump housing, it blocks the drain hole. Then the fluid has nowhere to go but out, past the seal.

Like I said, Ford had lots of problems with the converter bushing moving forward and causing seal leaks--but that was decades ago (On the C4, I think--but I could easily be wrong.)

There's also a huge O-ring-type seal around the OD of the pump housing, that seals it to the case. Can't say I've ever seen one of those fail, but there's always a first time. I don't think that seal has much if any fluid pressure behind it. It should just be a matter of seepage--so my money is on the converter-hub seal/converter bushing as described above.
 

Jerryred94silvy

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Turns out it is the TC bushing. Thank you guys for all your help. I have a different trans in it now, in the meantime I'll figure out what I'm going to do with this old one, probably learn how to rebuild it:)
 
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