We currently have a 69 Chevelle in our shop, LS1, 4l60E. Continues to blow pump rotor. WE have shimmed converter deeper into pump. Healthy car, curious if anyone has ideas?

 

What is the hp output? Max rpm? What mods have been done to the pump? TransGo NOYOYO kit installed? May need a billet pump rotor.

 

You should almost never need a billet pump rotor. if you're really needing a stronger rotor, I would go factory 10 vane long before I use a billet 13 vane.

When are thy blowing up? Cruising, high rpm, right during first startup or during first drive?

 

Are you just putting new rotors in the same pump?

Check pocket depth and vane clearance.
Check for fluttering pressures.
Running the stock flexplate?

 

Customer purchased this engine/transmission combination from Jegs, said 500hp. Transmission pump does not have any updates we can see, just a billet converter. Last time we shipped it over to our transmission guy, he replaced complete pump. We shimmed converter for deeper contact, current blown up rotor indicates riding about 1/2 way, no damage to pump this time. Customer advised he was not getting on it, just cruised through fast food line this time when it quit. Unfortunately we do it all other than transmissions, so looking for advise.....Appreciate It!

 

Lol of course, thats where all major problems happen.

 

You say you re-shimmed the same converter. Runout, balance, concentricity? Sounds like there may be an issue with the converter itself

 

Also make very sure level is good , Factory and aftermarket sticks are notoriously off. I have checked on the bench and observed this over and over, With a deep pan and filter it is not such and issue but with the stock car shallow it is , Low level will cause the pump slide to go crazy and pressure all over the place super high/ low.I have watched it on the dyno this can result in destroyed rotor and or slide or both. The level with engine running warm should be equal to the pan rail/case IMO. You can mark the stick for this while you have trans removed .
also NOTE that dowel holes in bell are not worn away have seen this and or dowels missing from engine .also do a line test with harness unplugged it should not exceed 240 psi in drive ideally around 200 to 220 psi.

 

Great advice from Performabuilt, but I'd bet with MaroonMonster on a bad converter.
Still a pressure check should be a given on any trans giving problems.
Correct me if I'm wrong but I think the full (hot) mark on the trans dipstick should be at the line between the case and the valve body. Obviously you have to remove the pan to check this, but it is a good thing to check any time the pan is off.

 

well where pan meets case or vb meets the case they are same position not higher than this however because you risk the blender effect if the standing fluid contacts the moving assemblies which will cause issues as bad or worse than low levels. But a nice deep pan from a truck or 05 gto and filter for same is the best cheap precaution it is what we use on all our units except the black edition which gets a much deeper pan with the corvette filter with snout pickup.