30th t/a

iTrader: (51)

my 4L80e has been completely rebuilt and I was told by the builder "your good for 1000 HP". The 1st time on the dyno the car gets to 4400rpm then instantly smacks the 6500 rev limiter. My tuner told me it is blowing through 3rd gear. it drives around fine. 1st gear & 2nd gear seem to work great on the street. Is there anything I should check before pulling the Transmission out?

thanks

jakeshoe

iTrader: (14)

If it flared that bad, it needs new frictions in the direct pack anyway. It may have a cut lip seal on the direct piston, or seal on the center support.

What kind of power are you making?

If you are making good power there are some hydraulic modifications that need to be made to that circuit that even some reputable builders aren't aware of or don't understand.

Any valve body kit used, or hydraulic mods done?

Edit:
I see the TT kit, so I assume well over 500 HP, answer my questions and I'll try to help you or your builder out with some mods to make this thing live to 1000 like it should (easily) do.

ShevrolayZ28

iTrader: (4)

Care to say who built it for you? You could PM me and I would keep it to myself , if you wish.)

Good luck with it either way.

performabuilt

iTrader: (25)

You say when its gets to this certain RPM its just jumps on the dyno are you sure its full of fluid? Seems odd at least to me that it would hold to a certain RPM then suddenly let loose rather than gradually slipping more and more as the power increased Just and observation.

ZZebes

iTrader: (10)

Maybe thats when he hits full boost and blows right by the power holding capabilities of the current tranny setup.

30th t/a

iTrader: (51)

459rwhp is the highest we've seen so far. That was a 2nd gear pull since the clutches are stronger than 3rd gear but it still did this strange problem in 2nd gear. A reputable, local guy built it for me. He has built a th400 that runs mid 9s NA for "TomtheRoofer" on this site, along with many other local high powered cars so i felt comfortable having him build it.

My tuner Dyno's Automatics Unlocked. He told me he takes it to about 3200rpm and nails it and it seems to be ok till 4400rpm, then it basically free revs in a instant to the 6500rpm rev limiter.

Darren P

iTrader: (1)

any chance it is blowing through the converter?

30th t/a

iTrader: (51)

I was also wondering about that but I dont know what that means. I was told it would do it in all the gears though.

Darren P

iTrader: (1)

it may not build enough boost to make enough torque in the lower gears

Pro Stock John

iTrader: (34)

Blowing thru the converter would be where the converter is too loose and it flares up bigtime. On the track it would slip too much and you drive through it. Your dyno guys should be able to tell if the trans is slipping or the converter is too big.

hawkls7

I have experienced the same cenario when my car was on the dyno i have the transgo hd2 kit . first i had a smaller diameter converter and i had the same symtoms that you are experiencing. my tuner told me that it was converter related so i then purchased one from yank which is a 3400 stall it has helped but what we are seeing now is that when you load the converter lets say to 4000 and then you nail it the rpm instantly goes to 6800 and sits there while the back wheels try to catch up and the stall goes to like 5200 . It might be converter related , they seem to not like dynos but on the pavement all is ok . Thats something that im in the process of figuring out

cablebandit

iTrader: (37)

i saw this once on an 80e. i think something was wrong with the sprag but i dont remember honestly. it would do what you said on the street....