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Discussion Starter · #1 ·
I replaced the pump gears because of wear on the drive gear from torque convertor contact. Now when I torque to stator support to the pump housing the gears bind. I have it narrowed down to two bolts hole that are near the part of the dump housing where the diverter is located. If I more than hand tighten either of those two bolts the pump binds. I located fro junk in the pump. And looked for burrs and sanded what I should might be high spots. Any clues on what I may be missing here.
Thanks, Bob
 

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Sounds like they may be twisted or out of round...but thats fairly unlikely. Have you checked the actual wide of the gears, they may be slightly wider than your originals? I think if there are any binding issues, I would put a new set in. They are only around $12-$15 in the US.
 

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Was just thinking...have you installed the pump gears the right way round. They have a small chamfer on the tips of the gears...they should face towards the converter...
 

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I'd say if your old gears turned freely than the problems with your new gears, they're probably a little too thick. Measure them both and se if there the same, as cfm60 says you might have to try another set.
 

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Discussion Starter · #5 ·
The ring set was slightly oversize. At the advice of a parts supplier (tranny builder) I used 220 grit sandpaper and solvent, with the sandpapaer on a piece of glass I worked both gears on both sides, sanding one gear then the other for about 30 minutes total. This was enough to bring the gear set into tolerance, We tried a second gear set and had the same results. We checked for burrs etc but couldn;t find any. Put the old gear set in and it worked fine. Measured the new gear set and it was .02 mm larger than the old set. My calipers are .02 MM resolution and it was repeatable measurement. .02 mm equals .000787 inches. So that is less than a thousands difference. Hard to believe that would bind things up. We also tired removing the outer gear leaving the inner drive gear and torqued the stator support to the pump housing. And it would rotate without restriction. this meant the outter ring was slightly out of tolerance. After the sanding treatment, the gear sets measure the same. I suspect there were some high spots that needed finishing...
I spoke with several mechanics and they suggested replacing the pump when gears are replaced. But I think I did the right thing. Time will tell. I should know in another day once I spin it up.. thanks for the help. And of course I would welcome any opinions.
Thanks, Bob
 

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I've used several sets of new gears,all measure .599.5" .Never had an issue. Think they were transstar brand,made in china.
 

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The three sets that I have in stock are all right at .5995" to .6".
I have never had any problem with gears fitting in the housing. If you take material off the housing you will make the gears fit tighter. Any debris in the body will make them bind. If the pump/converter bushing is pressed in too deep it can interfere with the gears and make them bind.
You can check the fit by placing the gears into the body, lay a straight edge across the housing and gears and check the clearance with feeler gauges. The gears should be about .0005" to .001" below the body. If they stick up at any point then you need to clean the body out and eliminate whatever dirt or burrs are interfering with the gears. Clean it out with solvent and blow it dry with air. Same with the gears, then check the fit. If the gears don't fit then my advice is to replace the pump.
Paul
 

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Discussion Starter · #9 ·
I cleaned the pump seat and stator support surface thoroughly. And surfaced the pump gears again for good measure. I couldn't help but think tolerance changes with heat, so I wanted to make sure to avoid a catostrophic failure of a bind condition during operation,, so I surfaced them again before re-reassembling the pump. Given that I've done this funky surfacing to the gears, besides a catostrophic failure of a bind, what else can result from this? Decreased pressure? If so, how do you measure fluid pressure? Do you tap into one of the cooling line at the radiator? If I need a new pump, want to try a different valve body due to other problems related to reverse etc. Considering another front servo because of measurebale wear patterns in the servo piston seal contact surface of the cover and now a new pump.... seems I should try finding a "WCZ" core.
Thanks, Bob
 

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Yep! 1/8" pipe plug. the hex head is 7/16" I believe.

I just had a thought about your gear bind problem.
Are you turning them with the converter snout or by hand?
Are they lubricated with ATF or transmission assembly lube?

Try this:
Put the gears in place with clean ATF on them and in the body. Assemble the pump with screws just finger tight (making sure that they are in the righht holes). Make sure the converter bushing is in place. Put the pump over the converter snout and try to turn it. If it turns then tighten the bolts down while it is on the converter checking as you go that it still turns easily. (tighten the bolts in small steps so that no bolt is more than 1/4 turn more or less from any other.

Let us know how it comes out.
Paul

<font size=-1>[ This Message was edited by: PaulS1950 on 12/7/06 3:47pm ]</font>
 

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Discussion Starter · #12 ·
I stopped at a trans shop and using assembly lube we finger tighten and had NO bind, however after tightening just beyond snug had the bind. This was true when using trans fluid as a lube as well. We then removed the outer gear and could tourque tighten all fasteners with NO bind. The test was done using the convertor snout. So we knew the outter gear was the culprit. Went back to trans supply house, fished my origianl gears out and torqued the stator support to the pump ousing then used the convertor and could spin up the gears no problem. At this point we were convinced the outter gears were slightly out of spec and measured .02 mm larger than my old outer gears. So using 220 grit wet/dry paper on a piece of glass with some solvent I went to work on the outer gear...working both sides adding solvent freshening up the paper and did this for about 30 minutes. Worked the inner gear for good measure. There must have been asperaties on the gear surface.. enough so to cause this problem. Bcause I cleaned up the gears, lubed them with assembly lube (vaseline) and torque the stator support to the pump housing and the pump gears turn freely on the the convertor snout. I brought the car up to temperature and have been driving it for nearly a week now without a problem. I was tempted to junk the new gears and go back to the old ones, but the old one had a deep indentation flat from convertor snout contact so I stayed with the newly "conditioned" gear set. If the gears expand from the heat, I;m banking thqat the pump assembly will expand at the same rate.
I should hav pout a doughnut magnet in the pan (like what's in my Bronco) and checked after week. I may do that this week-end I do have an extra magnet. What would I listen for or look for (if anyhing) to monitor this situation? i mean, will it sieze, will it drag..?. is there such a thing as a dragradation of performance related to this type of thing or will it flat out fail and sieze?
I have heard an occasional whining noise coming from the trans but I don't know what that is. I had faint and fleeting thoughts that it was the pump gears talking to me...
Hope I made the right decision. The trans supply house owner has been building transmission for 30 plus years and he's the one who gave the advice to "condition" the gears. We tried another set of gears and they did the same thing. I should probably look for a new pump so I'll avoid this type of problem next time I overhaul the tranny.
Thanks, Bob
So, to test the pressure from the test port, what type of gauge do I use?

<font size=-1>[ This Message was edited by: locorebob on 12/7/06 9:26pm ]</font>
 
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