904 Pump Removal

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T56MaxTorq

T56MaxTorq

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With the engine removed, I need to inspect the trans pump in-vehicle for damage after an engine thrust bearing failure. If I remember right I can just run the bands down all the way to lock the front drum to the front planet shell and pull the pump without the unit sagging and becoming unsplined.
 
I think that is correct. You might want to replace bushing and seal while you're there.
 
Well you pretty much just tighten the front ban on the outside. You don't have to tighten the rear band and take off the pan and all that I don't think. I'm not sure sagging or becoming unsplinde would be too much of a problem. I mean once you take that pump off and back that not off for the band there shouldn't be any reason why you just can't pull the drums write out and inspect the clutch is also? They will be just right there at that point. And if you have any suspect of them being worn in any way it would be a great time to change them. Personally I just don't like taking the pump off without and go ahead and rebuilding everything knowing the rebuild kit is just a tad over $100 and I would probably have 25 to $30 and just buying new seals and gaskets for what you're doing.
 
If you're not going to pull the tranny out then you definitely want to lock the front band down. Even so, getting the pump back in will still be an exercise in patience. Trying to get the pump back in without locking the innards in place is nearly impossible in the horizontal position. Been there, tried that.
 
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Seems like less trouble to pull transmission than to pull engine, but its already out. Pump comes out easy with a slide hammer.
 
I'm assuming you know that to install the front pump you need two guide pins to easily slide it on.
 
Thanks guys.

Sounds right to just tighten the front band and pull the pump

Jpar - trans has only 10 hours on it since overhaul. Plan is to drain and inspect filter. If contaminated, then trans will come out. I don’t want to remove the drums because I would never be able to respline the front drums clutches into the rear and get the sun shell to line up simultaneously.
 
dart_68 said:
If you're not going to pull the tranny out then you definitely want to lock the front band down. Even so, getting the pump back in will still be an exercise in patience. Trying to get the pump back in without locking the innards in place is nearly impossible in the horizontal position. Been there, tried that.
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Agree with you on that! Although I did rebuild a truck 727 from pump-sprag with it installed in the truck. Huge pain making sure that the drum, clutches, and sun shell were installed correctly. With the assembly stacked up on the bench, I measured the gap of the shell-drum. Then played with it til I got it right when it was in the truck, held it upright long enough to tighten the band up and slide the pump on. I was a lot younger then. I’d break my neck, now.
 
Ideally the trans will be standing on it's tail, then everything stays in there by gravity. I stick the tail into an old wheel so the m/s is off the floor. Then I pull a drawer open on my bench, and stand the trans up in the niche thus created with a little rear-lean so it can't fall outta there. I lever the pump-house outta there using two crow-foot bars under two bellhouse bolts threaded into the places designed to receive them. Easy peasy.


But you can see the pump-lugs by peering thru the seal. The rest of the pump should not be damaged. If it spins freely then I myself wouldn't bother to take it out. But then, I would have done a pressure test prior and probably not have taken the trans down at all. I have replaced that thrust bearing without even loosening the crank, just spun it into place. I'm a lazy sob,lol.
 
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AJ/FormS said:
Ideally the trans will be standing on it's tail, then everything stays in there by gravity. I stick the tail into an old wheel so the m/s is off the floor. Then I pull a drawer open on my bench, and stand the trans up in the niche thus created with a little rear-lean so it can't fall outta there. I lever the pump-house outta there using two crow-foot bars under two bellhouse bolts threaded into the places designed to receive them. Easy peasy.


But you can see the pump-lugs by peering thru the seal. The rest of the pump should not be damaged. If it spins freely then I myself wouldn't bother to take it out. But then, I would have done a pressure test prior and probably not have taken the trans down at all. I have replaced that thrust bearing without even loosening the crank, just spun it into place. I'm a lazy sob,lol.
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It spins freely and the pump lugs are still fresh. I’m not sure what ruined the thrust bearing. I had to bolt the trans up, in-vehicle, twice. From what I know, I could have damaged the thrust bearing then.

I did not do a pressure test unfortunately. I should have, because we might also think that the torque converter created high pressures that trashed the thrust bearing.

If the pump is trashed for good, would the shavings end up In the pan or would they be entrapped in the pistons and servos? Unable to escape.
 
With transmission mounted to block,torque should have a little wiggle room, enough to spin it to line up to flex plate.
So if its tight, perhaps lugs werent engaged in torque.
 
You might not want to hear this but, over time, a fine bunch of "dirt" will accumulate in any spinning parts in there, because they act as centrifuges, specifically inside the clutchs.Eventually, a fine black dust will permeate everywhere.
But
so long as the filter is functioning, clean oil is circulating.
 
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