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Discussion Starter · #1 ·
I have a performance built 4L80E. Has billet input, direct drum, good stuff etc etc.

Has a Circle D triple disc converter that has been in the car for over a year but this issue started to happen lately.

Has approx 1/4" spacing to the flexplate before bolting up. Looking at the pump gear and converter on the bench you can see where it is riding and is obviously not bottoming out in the pump.

TCI flexplate looks good.

Engine is fresh so thrust bearing is good fwiw.

Pump gear surface looks like it is coming apart and in turn grinding into the pump.

Any ideas on this?


Combo is turbo around 1100whp, no dragstrip action its a roll racer so it sees full boost in top of 2nd, 3rd, 4th with converter locked in 3rd and 4th.

 

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Based on the supplied foto this wear is usually the result of the gear being thrust into the pump cover. This is of course providing that the pump is not or has not been cavitating. A close inspection of the driven gear load bearing journal will yield additional information in some cases.If the bearing journal is not worn suspect the gear is being bottomed out. Extreme wear at the journal combined with the wear present in the foto is usually the result of cavitation , but can also be a result of the removed material passing thru the gear pocket so it may be difficult to prove unless viewed by someone with extensive transmission experience.
 

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You say you are pulling the converter from the trans up to the flexplate 1/4" when installing the trans? Its possible that you are so far out of the pump gear that the edges of the converter hub and the gear are creating a cam effect and driving the gear into the stator half. Normally this is seen with not enough clearance or a ballooning converter. Wear marks on the inner gear and the hub inner may tell the story.


Hutch
 

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I've always done 1/8" pullout. So I'll go with what the experts already said. Easy fix though!
 

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We had this happen on a big turbo setup about 9 months ago. I was not involved on the install, but was told all clearances were correct, which your 1/8 is perfect. On a side note - We have found the 4L80 to get a little better flow when converter spacing is .125-.150 range. So make sure it is al least .125+. We checked out the converter for the guy and everything looked great. Converter hub was not even messed up, showed no signs of gear damage. He got a new pump installed and away he went. Interesting you mention the grounding problem, the gear does look storage/pitted. Maybe some of the trans experts can chime in on that....

Chris
 

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Has anyone seen this caused by inadequate grounding? It all looks good except for this side of pump gear and body.

Looking at this photo, it appears the pump gear was reversed or installed upside down in the pump..
Can you take some pics of both sides of the gear and with the gear on the converter hub ?
 

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Discussion Starter · #15 ·
One more question.... Did you change anything lately. More power, coolers or any trans settings?

Went to a Holley Dominator EFI and changed turbos from 67s to 76s. It only making a little more power right now. Around 1100whp.

Chris
You said you had 1/4" pullout. So repair the pump and set the clearance properly and you're back on the road again.
Then I corrected my myself and said 1/8. Maybe its still the issue though if its not engaging the pump gear 100%.
 

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Does the gear go over the hub easily and when on fully , does the hub extend past the end with the dots on it? Have you checked the thrust in the motor? Some action is pushing that gear into the back cover , this damage is as a result of a direct push and when seen normally points to installation problems or converter ballooning.


Hutch
 

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This gear as pictured has the wear on the chamfered side of the pump gear..This chamfered side should face the torque converter.. Not the stator support...If installed upside down or reversed in the pump body, it will bottom out on the converter hub with less converter travel...
 

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Discussion Starter · #20 ·
Does the gear go over the hub easily and when on fully , does the hub extend past the end with the dots on it? Have you checked the thrust in the motor? Some action is pushing that gear into the back cover , this damage is as a result of a direct push and when seen normally points to installation problems or converter ballooning.


Hutch
Gear slides over easily but doesn't have excessive play.

The hub goes into the gear 75% of the way. The picture shows how far.

The engine has been freshed with a crank polish and new bearings this year but crank thrust has been checked and is very little.

Converter is on its way to CircleD to get cleaned and checked. I didn't notice anything obvious with it looking at it.

Thanks for the help everyone.
 
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