Transmissions and Drivetrain Need help with your trans? Problems with your axle?

Can anyone read the wear pattern on 700r4 torque converter hub

Old 10-28-2011, 10:48 AM
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Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Can anyone read the wear pattern on 700r4 torque converter hub

Can anyone on here read the wear patten on a torque converter for me?

I was having issues with fluid leaking somewhere inside the bellhousing area. We replaced the seal and it didnt fix it. We tried to look for cracks in the converter and couldnt find anything. We looked around the pump and it doesnt appear to be leaking from there. The new seal still looks good.

However, when we were looking at the converter hub, the wear pattern on it looks weird to me. The ring around the hub that has been "polished" doesnt look like I would expect. I would think that it would go around the entire hub at the same depth. However if you look at mine, on one side of the hub, the polished part dips lower on the hub. I have no idea what causes these wear marks, I was just hoping someone on here did and could tell me if something looks wrong. We are having a heck of time trying to find this massive leak.

Thanks

Here are some pics:









This picture right here gives me some concerns. The hub's internal has some heat discoloration to it. I had issues with this converter new. It wouldnt fit on the trans and I had to send it back. They claimed nothing was wrong with it but somehow when it came back it went on just fine. I dont recall seeing the discoloration there before but I may have not paid enough attention to it then.



Any insight? Thanks guys.

Brad
Old 10-28-2011, 03:30 PM
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Re: Can anyone read the wear pattern on 700r4 torque converter hub

Looks like you may have a worn or damaged front pump bushing. The area where the seal runs looks fine.
Old 10-29-2011, 03:15 AM
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Re: Can anyone read the wear pattern on 700r4 torque converter hub

There's either excess runout or another dimensional out-of-round issue.

AFter measuring as much as I could on the converter, I'd probably bolt it up to the engine and rotate things to check runout, then I'd have pulled the pump.

Good luck. It might be easier to just have the converter gone through and get a new pump but who wants to do that without knowing what the issue was?

edit: come to think of it, I bet the halves of the pump aren't aligned, distorting the bushing.

Last edited by jmd; 10-29-2011 at 03:29 AM.
Old 10-31-2011, 02:09 PM
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Re: Can anyone read the wear pattern on 700r4 torque converter hub

Right now Im looking at checking the flexplate, checking the thrust bearing, checking the converter, and finding someone to check/replace the pump bushing.

I will post up more as I can. The car is in my dad's garage 2 hours away. I dont get much time each month to work on it.

As cheap as flexplates are, I may just go ahead and buy a certfied one and put it on just to be sure that it isnt a cause.

Thanks everyone.
Old 10-31-2011, 06:13 PM
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Re: Can anyone read the wear pattern on 700r4 torque converter hub

I definitely see where the front pump bearing seems to be out of alignment.
Old 10-31-2011, 07:01 PM
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Re: Can anyone read the wear pattern on 700r4 torque converter hub

I found two TSBs concerning front pump bushing wear. TSB 87-54 deals with converter hub finish and warns of any scoring at all. It says that the converter hub must have a mirror finish. You can use very fine wet sand paper, wetted with trans fluid or solvent to finish the hub. TSB 86-1 deals with converter hub runout and recommends a visual check followed by use of a dial indicator to determine runout of less than .010". You may better off just replacing the converter. The latter TSB also mentions the flexplate and the crankshaft end where the pilot centers. Check the flexplate for any sing of cracking, bending, warpage, or damage to any of the bolt holes. Check the crankshaft pilot hole for any wear. You can solve any issue with the crankshaft by cleaning the pilot hole and making sure that the converter pilot engages firmly beyond any wear area.
Old 10-31-2011, 07:11 PM
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Re: Can anyone read the wear pattern on 700r4 torque converter hub

Originally Posted by ASE doc
I definitely see where the front pump bearing seems to be out of alignment.
Is the bearing the same as the bushing?

Can you point it out on this diagram? http://www.transmissioncenter.org/70...Up_Diagram.htm

I am guessing 70, 71, or 72? Sorry I couldnt find the list that matched up to this diagram.

Thanks

I am probably going to replace the flexplate just to be for certain. I am also going to check the converter this weekend for runout.

Thanks again for all the help. I will post up what I find.

Last edited by 3rdgenmaro; 10-31-2011 at 07:17 PM.
Old 11-01-2011, 11:34 AM
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Re: Can anyone read the wear pattern on 700r4 torque converter hub

Thanks ASE Doc for all the help.

My dad spoke with a guy that he works with that builds transmissions for some of the local hotrodders and racers in his spare time. He is going to take the transmission and converter and check it out and fix it. It will be a couple of months with deer season and the holidays coming up. I will post up whenever I find something out.

Thanks again for all the help. I really appreciate it.
Old 11-01-2011, 12:30 PM
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Re: Can anyone read the wear pattern on 700r4 torque converter hub

I would say it's #70 in the exploded view. The bearing and bushing are the same thing. I don't remember if the 700 uses a needle bearing or a bronze bushing. Good news on getting the trans to a builder. I'm sure he'll catch what's going on once he gets a close look at the pump and converter. Be sure to check out the crankshaft and flex plate too. Good luck.
Old 11-15-2011, 11:28 AM
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Re: Can anyone read the wear pattern on 700r4 torque converter hub

3rdgenmaro im going to hop on your thread if you dont mind, me and him talked on my thread and we are having pretty similar problems i just replaced my flexplate because it was cracked saturday night and right after i put it all back together it started making this noise that sounded like an exhaust leak well after checking under the car i learned the sound is coming from around the front of the trans. and it is leaking from the input seal. im fine with replacing the seal but the noise is making me nervous.
Old 11-16-2011, 11:30 PM
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Re: Can anyone read the wear pattern on 700r4 torque converter hub

One thing that I forgot to mention is making sure that both alignment dowels are installed in the back of the block. These dowels are what hold the crank and trans input shaft in alignment. Was juat reminded of this yesterday when I diagnosed an engine noise on a Toyota RAV4. The flexplate was completely blown out around the center because of a missing dowel.
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