4SFEDSS

iTrader: (19)

Im considering swaping out the t56 in my 3rd gen for a 4l80e. If anyone has done this im curious what you did for a crossmember as the t56 is quite a bit shorter than the 80e. And this concerns me because the t56 mount is already pretty far rearward from where the crossmember itself mounts on the chassis.

mikesanto70

Did you put the 4l80e in, looking at your sig it looks like u did, I'm doing a similar set up like u a lq4 w/ a t76 and want to put a 4l80 behind it, any advice?

4SFEDSS

iTrader: (19)

Well bmr actually makes a crossmember for it buts its nowhere near actually lining up. This has been a common problem with this acording to others on thirdgen.org. I did use the cross member but I had to make alot of modifications to it and built a mount for a spohn custom length torque arm. I will get some pics as soon as I can.

Pocket

iTrader: (22)

Using the 4L80E too and built my own crossmember

the_merv

iTrader: (88)

The T56 is about 3" shorter than the 80..the Mount on the 80 is pretty much where the T56 would end at..

Pocket

iTrader: (22)

Kind of sort of not really...

Crossmember shape for an '80E
http://www.thirdgen.org/techboard/at...e-swap-jig.jpg

Compare it to the end of the pass subframe, dimple is a good reference point. Notice how its a good 2" past
http://www.thirdgen.org/techboard/at...wap-dshaft.jpg

Off the Hawks website, you can again see the dimple in the pass subframe in pic #2. Mounts is approx 5" forward of that point
http://www.hawksthirdgenparts.com/tr...t566speed.aspx

http://www.thirdgen.org/techboard/tr...l80e-swap.html

4SFEDSS

iTrader: (19)

heres some pics

the_merv

iTrader: (88)

Can't see half of your links..what I meant was the T56 total length..which is about 31.5"..is close to where the mounting point is on the 4L80E..I put them both side-by-side at the shop..just for ****'s n grins to compare.

schuller

what did you use for your cross member? Easier to order one and modify it or start from scratch? any tips you could help me with would be great!

Pocket

iTrader: (22)

Start from scratch. IMHO the U shaped crossmembers most run put too much leveraging stress on the subframe. The trans is crazy heavy on its own. I incorporated the trans crossmember mount into my SFCs, so its a strait across design

To get the trans perfectly aligned, you will have to fiddle with the motor mounts, possibly build your own. I used one behind a 6.0 using the hawks (crooked) LS1 stands. With the trans jacked all the way to the top of the trans tunnel was still tail down 2-3*. You will have to fabricate custom shifter arm and bracket. Real estate is extremely tight down there

DS length changes
Custom lines require a specialty fitting for the rear port

All I can think of right now