I have a ? is the bellhousing bolt pattern the same for all ls series engines? I am looking at possibly using the allison 5spd auto trans and was wondering if it would bolt up to the ls1. GM uses this trans in HD truck apps. It would be nice if it did because this trans is built to take the torque of the duramax deisel and the 8.1v-8 and it has 5 fwd gears.

Just upgrade to the 4L80e if you want something beefier than the stock 4L60e.

Apparently you have never seen the Allison transmission (LCT-1000). I have had to replace them on the trucks. I can lift a 4L60E by myself with no problem, but myself and another tech struggled to get the Allison out of the crate and on the transmisison jack because its just so big and heavy.

I've never tried to install one in an F-body, but I'm more than willing to bet that it would NOT fit and would add a ton of weight to the car.

You would also need a seperate transmission control module which would not be easy either.

yes I have seen them(pulled out or lifted no) we have them in about 10 trucks where i work. as far as a trans controller I believe you could use a pcm from the 8.1 gas engine

There lies the other problem. The 8.1L PCM is NOT the trans controller. Next time you pop the hood on one of your trucks, look at the PCM mounted on the left side of the engine bay. Right next to the PCM is the TCM (transmission control module). That is the actual controller for the Allison transmission, and receives data from the PCM via serial data (CAN or Class2).

Size and weight differences are substantial, making it pretty impractical, but if you think you can do it, by all means, knock yourself out!

mostly just trying to gather info would be nice to have the extra gear in a automatic

You can get a Gear Vendors unit on the back of the 4L60E.
You could also just get a 6-speed manual. Its real nice to be doing 80 MPH at about 1850 RPMs in 6th gear.

GM reportedly has a 6-speed auto in the works rated at 400+ lb/ft tq, might be worth some research.

do you have any more info on it

something like this maybe

Hydra-Matic 6L80 Specifications

Type: Six speed rear-wheel-drive, electronically controlled, automatic overdrive transmission with torque converter clutch. Clutch-to-clutch architecture with integral electro/hydraulic control module

Engine Range: 4.4L

Assembly Site: Ypsilanti, Michigan

Applications: Cadillac: STS-V, XLR-V




the engine this trans is used behind make 440hp and 430lbft

Great researching, thanks for posting it.

That would solve the weight problem posed by the Allison trans.

so the weight is taken care of what about the bolt pattern on the bellhousing I can't find anything on it

well I found this that they are putting it in the corvette6L80 specs

Great stuff! Tap up/tap down shifting!! And it wants Dexron VI fluid?!? (I though Dex III was the top of the line)

What about the 5L50E that backs the Northstar? How much can it take and can it bolt to the LSX series engines?

I don't know what its rated to handle, but keep in mind, the "50" in 5L50E is a relative torque rating. Which means a 4L60E can handle more torque then a 5L50E. The 4L80E can handle even more.
To put it into perspective, the TH400 was renamed the 3L80, which is why the 4L80E is often refered to as a TH400 w/ overdrive.

So the only real benefit from the 5L50E versus the 4L60E is the added gear, because judging from its torque rating of "50", it shouldn't be able to handle as much as the 4L60E.

And on the subject of 4L60E, you'll notice that when they made the revisions to the 4L60E to put it behind the 6.0L, they beefed it up and rated it a 4L65E.

between the weight, and the power loss, the allison is a waste.
it will eat at LEAST 40-50hp and the weight will make your car feel as if you lost 100hp....

even a 4l80e is not needed unless you are beating on your car hard.
they eat quite a bit of power too.
i wouldnt put a 700r4 or a 4l60 into anything..... KAPLOW! BOOM! GONE!
LOL.


good luck.