From the pics the pump gears look too tall, they come in four different sizes. Put a straight edge across the pump body face and be sure the gears are below the crescent surface.
CK5
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77K5. The IronMaiden...9/2 headed for Blazer Bash 20!
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I think you definitely found the problem! Its just too bad all that junk was pumped everywhere probably.
My book says pump gear end clearance should be between .0008-.0035 with a feeler gauge and straight edge.
Dave I remember you saying you had to slide the converter back up to the flexplate an 1/8" or so, and I see the drive tabs are away from the motor side, so something else such as debris or clearance issues must of caused this gear failure...
Is that one of the drive tangs in the red circle?
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Tranny's are yucky.
They’re not so bad once ya get used to them....LOL
Heath I’m not sure if that is a tang piece or not, I will try to reconstruct the scene of the crime and post more pics.
I have two more 400 cores, so should I get a rebuilt pump or pull one of those core pumps and check it out, and if it’s a good piece I can switch the boost valve into it and run it?
@Greg Ducato the convertor is on its way UPS. Should see it on Friday.
Heath I’m not sure if that is a tang piece or not, I will try to reconstruct the scene of the crime and post more pics.
I have two more 400 cores, so should I get a rebuilt pump or pull one of those core pumps and check it out, and if it’s a good piece I can switch the boost valve into it and run it?
@Greg Ducato the convertor is on its way UPS. Should see it on Friday.
The clearance between the flywheel pads and convertor was slightly less than .200, with a consistent gap at each pad.
The flywheel looks good and is SFI rated. I bought a Pioneer unit with the 6 pad mounting that is compatible with this convertor. Should I go with that one? The 3 bolt unit has not had any issue since I first fired the engine 8 years ago.
I have the Cliff Ruggles book plus the GM service manual as well.
The flywheel looks good and is SFI rated. I bought a Pioneer unit with the 6 pad mounting that is compatible with this convertor. Should I go with that one? The 3 bolt unit has not had any issue since I first fired the engine 8 years ago.
I have the Cliff Ruggles book plus the GM service manual as well.
Also possible there is debris or scoring that prevents the gears from sitting down where they should.
Probably the tangs breaking off is the last thing that happened.
If its a good core and the gear end play is fine I would run it. You can also do the gear test where you place the inner gear down into the outer gear on a smooth flat clean surface. Then try to slide the inner gear laterally out of the teeth. If the outer gear doesn't get pulled by the inner gear, supposedly the gears are worn.
If I had .200 thousands clearance I would put a .060 washer between the pad and flexplate at each bolt. Just make sure they are the same thickness with a caliper, many washers don't measure the same and you have to sort through them all to get three exactly the same thickness. I do not think this is your problem, just a general observation, I like to see the clearance between 1/16 - 3/16", so its quite common to shim it a little. The tang is only so long so you don't want the reduce the engagement by almost half or anything, but at the same time too little can bind up under operation. I usually shoot for 1/8" clearance.
I agree, the tangs don't just break off for no reason. It probably was getting hot from rubbing or debris or too tight, then it started to seize up and the tangs broke off.
Dave, did you dissassemble the pump before? If so, what do you use to realign the pump halves when you bolted it back together? You can either use the case itself(has to be empty enough to slide the pump in backwards without a gasket) or I have used a couple huge hose clamps run together. You just have to make sure the pump halves are aligned before you tighten the bolts or it could possibly cause the gears to bind and seize up. How does the pump bushing look for the converter snout, is the wear even or more on one side only?
EVERYTHING was apart when the convertor shit itself. I cleaned everything thoroughly including the lines, radiator cooler, auxilliary filter and auxilliary cooler. I used the foaming flush in a can, until it came out clear, then thoroughly blew everything out with compressed air. I think the auxilliary filter saved a bunch of the convertor sprag from getting back into the trans.
so yes the pump was apart, and I took it to the trans shop for some bushing replacement, and he added the new set of gears at that point, then aligned it with a band and bolted it together.
so yes the pump was apart, and I took it to the trans shop for some bushing replacement, and he added the new set of gears at that point, then aligned it with a band and bolted it together.
I reconstructed the gears....the tangs are completely accounted for, and at least 3 pieces of the crescent are present. If you look at the pump housing, you can see where the crescent has been broken off. Not sure why or when that might have happened, but the large gear has debris on the outer surface that must have created a binding situation that perhaps seized that gear from turning and then broke the tangs off the drive gear. Thoughts?
the convertor bushing looks ok, except for where I had to wiggle the convertor back and forth to get it out of the pump...I think that's what the marks are on the bushing. that bushing was replaced as well, and again it didn't feel to be tight while I was assembling the convertor to the pump.
the convertor bushing looks ok, except for where I had to wiggle the convertor back and forth to get it out of the pump...I think that's what the marks are on the bushing. that bushing was replaced as well, and again it didn't feel to be tight while I was assembling the convertor to the pump.
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Glue it and run it? 
I agree with Heath. A good used pump is as good as a rebuild. Best to avoid the old pump housing altogether.
It's possible your "new" set of gears was defective. Why were they replaced? I had an oil pump (3800 oil pump is similar to this) chew itself up and it looked like casting flash in the housing had been coming off. It could have been an effect and not the cause but I couldn't find anything wrong with the whole rest of that engine. Or you may have had debris somewhere. Hard to ever know for sure.
I agree with Heath. A good used pump is as good as a rebuild. Best to avoid the old pump housing altogether.
It's possible your "new" set of gears was defective. Why were they replaced? I had an oil pump (3800 oil pump is similar to this) chew itself up and it looked like casting flash in the housing had been coming off. It could have been an effect and not the cause but I couldn't find anything wrong with the whole rest of that engine. Or you may have had debris somewhere. Hard to ever know for sure.
I did this once and found once that once the ridges were filed down, the handful of standard washers all measured out really close. The problem is the stamped edges, which wouldn't really affect them for their intended use like it could here.
Invest in a good used pump assembly and you will be fine. Be mindful of pressure regulator valves and springs, be sure there is no mismatch with the pump casting numbers. Also, don't go hog wild with line pressure, keep it below 200psi at wide open throttle, maybe even less than 175psi. Excessive pressure could have busted these gears.
One more thing, I don't remember if we talked about grounds. Be sure there is no paint on the bellhousing face or block face and add a good ground strap from trans case to chassis. We have seen many instances of poor grounds destroying pumps.
I agree, why were the gears replaced? Were they worn, from what I have read that is rare, I haven't yet seen a used set from a good core on a TH400 or a 4L80 that weren't useable as is. I would be checking the end clearance right now with a piece thats left over, a straight edge (metal scale) and a feeler gauge are all thats needed...although ideally the trans shop would of done that when they put them in?
I feel like the debris outside the pump gear is likely more of an effect than a cause, but its possible. It appears that piece I was asking about was part of the pump case, makes more sense, I was thinking it would be weird for a tang to get out there, I suppose its unlikely but possible. That piece makes more sense.
I feel like the debris outside the pump gear is likely more of an effect than a cause, but its possible. It appears that piece I was asking about was part of the pump case, makes more sense, I was thinking it would be weird for a tang to get out there, I suppose its unlikely but possible. That piece makes more sense.
Greg we did talk about grounds last go around, I have a 10ga ground from case to frame
Heath the trans shop replaced the gears as I recall the surface of the large gear was flaking off.
Heath the trans shop replaced the gears as I recall the surface of the large gear was flaking off.
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Ahh, strange. I didn't know that. So are you thinking its possible some of that debris may have been left in there? Or it had already scored the pump case?
T
tenderfoot
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I hear you, I usually try to measure the actual material thickness, if you measure across the entire flat washer the edges and flatness greatly increase the variance, and that will likely be flattened to actual material thickness once torqued. I usually measure small portions of it with the tip of the caliper, which isn't exact but close enough since we are only looking for the deltas.
Even when you ignore the edges and flatness variance, many washers in bulk vary in thickness quite a bit, sometimes more than .030". The tolerance from McMaster for a 3/8" USS washer is .064-.104" thickness, and the SAE is still .051-.080". You must of gotten a good batch.
Most of the time it doesn't matter, but in this instance it does.
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Have you checked the gear end play with a feeler gauge? I know it wasn't tight when you installed it I am just wondering how much clearance there was....you could still try to check it with the outer gear and or the largest piece of inner gear...
The good thing is you definitely found the problem, I'm just not sure what caused it? Although a used pump you check over and clean should fix it.
The good thing is you definitely found the problem, I'm just not sure what caused it? Although a used pump you check over and clean should fix it.
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