Allison on a 96- 6.5L TD Surbarban

[JOLLYFERT]

Can anyone on this board tell me if the new Allison transmition can be mounted on to a 1996 GMC 6.5l TD Surburban? Thanks

[AndyL]

It would bolt to the engine, but would not fit in the tranny tunnel. You might be able to squeeze it in with a body lift.

How would you shift it? I have heard talk of stand-a-lone computers but have yet to see them available.

[ogrice]

Forget the allison tranny with its heavy 5-6 speed planetary gear sets. With out an built engine that will make use of the power holding capability of an allison, its overkill(hence Durabux/allison combos). How about putting the one piece aluminum drive shaft in place of the old dual shaft setup.?
That sounds like a good idea.

[dieseldummy]

MP's power project fit one in a classic styled pickup so I'm sure it could be done to a burban. If I'm not mistaken the 1000 series uses a standalone controller as it is in stock form. That's just what I've heard though. I've often thought of putting one in my pickup when the time comes for a rebuild of the tranny. It might be overkill, but it sure would be nice to have that/those extra gear ratios while towing.

[mklein]

The 1000 will fit with a two inch body lift - at least that is what the techs that did the early bucks for GM told me. The problem with the trans, as mentioned earlier, is the controller. It is a stand alone unit, but requires in from the engine controller via a J1939 data bus. Unless theres a aftermarket controller, or some other piece of equipment from some other application to control it, it becomes difficult to integrate with the vehicle. But the trans really makes the engine perform nicely. We have one behind a 6.5 in a P type truck. Huge difference in performance as compared to the 4L80.

[More Power]

PCS (http://www.thedieselpage.com/reviews/pcstrans.htm) had a standalone TCM under development several months ago. Should be up and running by now.

Not surprisingly, the Allison programming and electrical harness layout is very similar to that used with the 4L80-E.

You'll need a cable shifter assembly, due to the Allison selector shaft being located farther back than on either a 4L80 or 4L60.

MP

[mklein]

Hey, you were right, and PCS does have a controller ready to go, with the setup software for 850 bucks. I think I may have to start working on that right now.

[JoeyD]

I think performance would improve with the Allison. Better 1st gear and closer gear spread. Does the aftermarket controller maintain tow haul and grade braking?

[More Power]

If it's in the budget, you could also drop in a Duramax radiator. It'll fit the 6.5 truck rad core support exactly like an aluminum 6.5 radiator, after removing the mounting ears on the new rad.

This way, you'll get the 5/8" fittings for the in-rad ATF cooler. For heavy towing, you'll need both the in-rad & external cooler.

I'm just using the in-rad cooler in Lil Red, which produces ATF temps that track engine coolant temps (or less, depending on what I'm doing).

MP