I have a 2008 corvette, automatic that was converted to the 4l65e.
I noticed some slipping last outing and drained the fluid (looks like liquid gold).

I bought a 6l80 and was going to swap it back to 6 speed and it looks like I'll have
to change everything, trans, rear end torque tube. I've been searching, but
cant find the answers I'm looking for.

I'm back and fourth on rebuilding the 4l65e or 6l80 swap.
It's a cammed ls3 for street/strip if that matters.

 

If all of those parts need to be changed to get back to the original trans, your answer is easy, a rebuild of what you have

 

I would never consider putting a 4L65 into a car that came with a 6L80. That's just dumb. Fix it right and sell it, who knows what other stupid things the previous owners did.

 

Suggest contacting RPI who're xmission specialists used by many CF members.

 

Yeah the 4L65 and the 6L80 are two different torque capacity transmissions. 65 vs. 80.

A cammed LS3 just might be beyond what a "65" tranny can take.

On a prepped launch pad, certainly.

 

Depends, and it can be far from dumb depending on use case. For a stock or slightly modified, yeah; but there is a reason RPM doesn't offer 6L80 builds and why Z06 and high hp owners have RPM swap 4L65e's. But to your point, there is a mystery why the previous owner swapped if the engine is now stock. Leads me to believe it was probably highly modified at some point in the past and then returned to stock and sold - not cool.

To the OP, give Jermey a call at RPM. They have 4l65e that are rated to over 1000hp and everywhere in between. If you search, you will find plenty of current and former 4L65 owners that beat on them constantly at the strip. I just went over my build with Jeremy last week.

 

Does it have a high stall convertor? Wondering out lout if that is your slippage...is all..



Good luck getting her like you want...

 

It was my original plan, but I had 2 transmission guys tell me it wont take abuse...

 

It was my original plan, but I had 2 transmission guys tell me it wont take abuse...

 

Not a high stall at all, feels close to stock

 

[QUOTE=csnow;1609654936]Depends, and it can be far from dumb depending on use case. For a stock or slightly modified, yeah; but there is a reason RPM doesn't offer 6L80 builds and why Z06 and high hp owners have RPM swap 4L65e's. But to your point, there is a mystery why the previous owner swapped if the engine is now stock. Leads me to believe it was probably highly modified at some point in the past and then returned to stock and sold - not cool.

To the OP, give Jermey a call at RPM. They have 4l65e that are rated to over 1000hp and everywhere in between. If you search, you will find plenty of current and former 4L65 owners that beat on them constantly at the strip. I just went over my build with Jeremy last week.[/QUOTT

They did the conversion years ago i believe. It was supposed to be "built".
I called them last year just to ask questions about the car and all i got was "We did a lot to that car".
Cant remember who I talked to tho...

 

Thanks for all the replies...
A good transmission builder my buddy uses thinks I took the converter out.
He told me a lot of reasons to go 6l80 and doesnt like the 4l65e
Haven't had time to pull it yet.

 

If the previous owner went through the trouble of putting a 4L65 into that car, there is a good possibility that the output shaft was changed to mate to a Z06 diff to get the 3.42 gearing and strength. Make sure you have the stock differential or you're going to be trying to source a diff while your car is on the lift.

If your guy is correct, the stall going out makes a lot of sense. If the prior owner returned the car to stock and flipped the car, a stock converter could likely be overpowered by a built 4L65 in short order. They probably also pulled the cooler, so make sure you still have a cooler on the 4L65e. A new Circle D stall is only a bit over a grand. This would also allow you to have a bit more fun over stock even if the motor isn't modified. Either way, sorry your having issues as a new owner. I would pick up the phone and ask to speak to Jeremy directly.

Honestly, my opinion keep the 4L65. Your transmission guys are probably generalists, and they are right that the 6L80 is a better trans in stock form than the 4L65, but Jermey specializes in vettes and knows both transmissions better than most in the US. People who routinely break and abuse transmissions go to RPM. When built, the 4L65 is a very different story