LS1Transam99

iTrader: (6)

Back in March of this year I was at the track with my 1995 Camaro doin a burnout and while pulling out of the trough, it went out of gear when it was supposed to shift into 3rd. I lost all forward gears and reverse. The front pump rotor had broken into 3 pieces.

I had the transmission "refreshed" by the guy that originally built it and the pump was replaced. I sent the converter back to Edge and they cut it apart to check it out and everything was fine, including the run-out on the snout.

I put the transmission back in the car about a month ago and have less than 2,000 miles on it. I was driving up an on ramp and I got on it a little bit after it shifted into 2nd and it went out of gear when it was supposed to make the 2-3 shift. I lifted off the gas and rolled back into the throttle and it accelerated fine.

When I pulled away from a stoplight a few miles down the road, about 30mph I got on the throttle and it felt like it bogged like hell, felt almost like a carbed car flooding. It shifted just fine if I stayed under half throttle.

When I got near my house, I slowed to 30mph and floored it. It bogged again just like before, then went out of gear and no longer had any forward gears or reverse.

I haven't pulled the transmission back out, but i'm 99% sure I trashed the pump rotor again. With the converter checked out, proper converter to flywheel clearence (3/16" with the converter all the way in the trans) and the transmission supposedly checked out, I have no idea whats busting the pump rotor.

I tried to be as descriptive as possible, does anyone have any idea what could be tearing up the pump? The car has a 383ci LT1 with a 3500 stall Edge converter.

performabuilt

iTrader: (25)

Looks like you have the clearance right so I would guess possible excessive line presure also I would check that the flex plate is not cracked. But the BOGG you describe is interesting and makes me think maybe line presure could be the issue. I would check that max line with the harness unplugged is not over 230 psi preferably 215-220 psi is ideal .

Greaseymec

iTrader: (9)

I've seen billet pump rotors on a few units but dont know who sells them. Its not common to see a broken rotor on a tranny that has been in service for a while but it happens. I see most rotor failures just after someone has just installed a unit. After a short interview it uaually comes out that the converter was not seated all the way when the bell housing bolts were tightened. It binds on the pump rotor and cracks it. OOPS! Not saying that the case here but I have seen it. If a cracked rotor is the problem once more, try and find a billet rotor. It will give you time to troubleshoot a possible line pressure problem without worry of a cracked rotor. I just wish I could point you to someone who sells them. I would like to have a few.

Mec

LS1Transam99

iTrader: (6)

I should have checked the pressure when I got it back just to be sure, since I never fully understood why it broke in the first place. The comment about the flexplate does make sense though. The engine assembly is externally balanced in the rear, but the flexplate they sent me was a 168 tooth and wouldnt work with my starter. They had told me I could use a stock 153 tooth instead of the one they supplied without any issues. I wonder if not using the flywheel they supplied is putting a little extra vibration at the end of the converter, that would make sense. Not sure if that explains the bog though. Thanks for the response
Man I wish I had looked for one of those after the first time it broke, thanks for the tip. I'm 100% positive I didnt make that installation mistake Though I know that's almost always the cause of a pump rotor breaking, these things typically dont see that much of a load.

I'm definitely gonna try and find a billet rotor for this thing, but I think I need to go ahead and order me a mini starter so I can use this flywheel that came with my engine assembly. I'll verify the fluid pressure if I ever get the trans back in the car

Thanks folks

LS1Transam99

iTrader: (6)

Greasy, I found a website that carried the billet pump kits. It's a TCI unit and it's nearly $470. Heres the link:
http://www.compperformancegroupstore...Category_Code=

Greaseymec

iTrader: (9)

Holy crap! Mucho denero!! That cost is for the entire assembly. I need to locate a source for the rotor. Thanks for the link. Find anything out with your unit?

Mec

LS1Transam99

iTrader: (6)

Yeah thats what I said I'll probably have to replace the whole assembly on my trans though, I'm just hesitant to do so until I pinpoint the exact cause.

71 #'s Chevelle

@LS1Transam99
Did you ever figure out the problem? I have put 2 pumps in in the last 2 years. Seems like they last 1 year then boom! Same here, I am purdy confident it was not on install,,, I got a billet pump unit and gonna have it put in in a few days. Gonna let GM go over it and check on line pressure. That's what I am ponder'n. When we got it,, the motor and trans had a "tune" in it with a Hypertech Power Programmer they gave us with the car and bein I put a "shift kit" in it along with the tune,, I think that's our problem,, not sure.