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Rebuilt transmission and now excessive crankshaft endplay?

Old 12-02-2016, 11:48 PM
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Default Rebuilt transmission and now excessive crankshaft endplay?

I had my daughters '96 JGC transmission rebuilt about 6 months ago and at first I thought all was good. I had to tool around town for a few days with my DMV paperwork incomplete so I could get the last of the sensors to reset before I could get it smogged.

During one of the visits to the smog shop, it made a horrible rotational grinding noise as if a bolt was rubbing on a rotating object. I took off the inspection cover of the trans and didn't see anything obvious but the noise eventually stopped after shutting the engine off for about 30 min.

On the way home (sensors still not reset) it did it again and I was limited to about 25 mph until I could pull over and shut it off. No amount of visual checks showed anything amiss and when I restarted it to go home, there were no further issues.
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Old 12-02-2016, 11:54 PM
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So I kept driving on and off until I could get it smogged and the regist. completed. After that, there were no further occurrences for the next few months until all of a sudden it started again when my daughter was driving. I got there but could not get it to repeat the issue. I took it to the trans shop as it was still under warranty. They looked around and checked it out and eventually had me come out to look at it on the lift without the inspection cover installed.

They used a large pry bar to move the crankshaft back and forth and it appeared to have a significant amount of movement. There was no way to measure it at the moment and they insisted that it would need a new thrust bearing that I could install myself as they felt the thrust bearing was worn.

Now I haven't looked into how to change this out yet but assume it is a half bearing somewhere in the middle of the crankshaft.

Last edited by quikduk; 12-03-2016 at 12:04 AM.
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Old 12-03-2016, 12:01 AM
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Now for my questions.

1. Before needing the transmission rebuilt, it NEVER made this noise.

2. After a full rebuild, this non-continuous issue began.

3. Presently I have the inspection cover removed from the trans bellhousing and so far, the issue has not repeated itself.

4. How can I correct this issue if I even have to and install the inspection cover again?

5. Is there something the trans shop could have done during the removal/replacement or rebuild that created this issue?

I am at a bit of a loss here and don't want to go back to the shop to complain or point fingers until I can rule out all other reasons for the issue. I don't even know if the play is excessive but was planning on trying to measure it somehow in my garage.

Any hints on measuring the play, why this happened after the rebuild or anything else is greatly appreciated.

Oh, one more thing is that when the engine is first started cold and the trans is put into either drive or reverse, it acts like it is low on fluid and it doesn't want to shift until I either rev it up a bit or wait 15-30 seconds. Is it losing pressure and if so why? Could the shop have done something wrong? Their excuse is that these Chrysler transmissions sometimes bleed down like that but I never had that issue before the rebuild so what did they do/not do right?

Help please as I need to arm myself with facts before going back to the shop.
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Old 12-03-2016, 02:28 AM
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You're talking about the engine crankshaft? That has nothing to do with or caused by the trans rebuild. The torque converter is designed to "float" back and forth about 1/4" normally, but is held in place by the flexplate bolted to the crankshaft. Normal crankshaft end-play limits are .002-.011".

Now, the flexplate bolts may be loose where it's bolted to the crankshaft or the flexplate may be cracked.

I've never heard of engine thrust bearings wearing out excessively before the bearing inserts themselves go bad. Even standard transmission vehicles don't wear out engine thrust bearings that often.

Look at the inspection cover an see if it's been stuck by the flexplate or crankshaft bolts.

Last edited by dave1123; 12-03-2016 at 02:31 AM.
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Old 12-05-2016, 03:25 PM
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did you or the shop flush the trans cooler before it was reinstalled?
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Old 12-05-2016, 06:25 PM
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Welcome to the forum!

None of this sounds good.

Which engine is on the vehicle?

It may be the the rubbing part was ground away to provide clearance.

What was being pried / observed to show the "excessive" end play?
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Old 07-18-2017, 11:42 AM
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All,

Sorry for the big delay in responding to your suggestions but work and family life sometimes has to take precedence.

So to Dave 1123:

I did see some scraping on the inspection cover hence why it was removed. I will need to manually rotate the flexplate around and check the bolts as well as see if there are any evident cracks.

To marklar134:

I am unaware if they flushed the trans cooler. I would have hoped so but...

To wingless:

It has the 4.0L-6. They were prying against the flexplate. My "impression" of the "mechanic"...and I'll use that term loosley, was not good enough to inspire confidence in his skill set nor the workmanship despite the shop's reputation.

I will need to just get under it again and check it out for myself. I believe the 12 month/12,000 mile warranty may be expired now so I am likely on my own again...

Since this issue cropped up, another surfaced that is outside the scope of this post but will require more work so I'll post on that issue elsewhere.

Thank you all for your comments and suggestions and I'll update all when I get time to check it out.
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