Allison a/t swap into m1008 questions

[GATVILLE]

Hey, im new to the forums here and have recently purchased an 86 m1008 and was thinking about swapping the trans out to something more practical on the highway. I would rather like to stay away from swapping gear ratio's, and was considering picking this up. I cant tell what the model is but i emailed the guy with a few questions.

http://albany.craigslist.org/pts/1383573018.html

id assume the bellhousing matches up to my 6.2 but can anyone help me as to what is involved in doing such a swap?

thank you.

[DmaxMaverick]

Welcome aboard!

It could work, but I don't think it is what you think it is (or want it to be). If you have an auto now, this Allison won't be any better, and perhaps worse. This tranny is from a medium duty chassis. It may have one more gear, but high will probably still be direct (indicated by the low first gear comment). The Allisons are as close to bomb proof as they get, but they come at a price: parasitic loss. If you are moving a lot of weight, it may be an improvement with the lower first, and closer gears. In the end, you will still have a direct high gear and an open torque converter (no lockup). The pic of the tag is useless. The price is right, though.

If you want an improvement over what you have, look for a 4L80E with a stand-alone controller (essentially a TH400 with OD and lockup converter). It'll be a lot more $$ than that Allison deal, though. A TH700R4 is about as good as they get for economy and simplicity, but they are weak by comparison. Other than that, you'll have to re-gear, or install an aux. OD (still more $$).

[GATVILLE]

thanks for the info, i'll probably go with my original plan and get a built 700R4. i just was curious as to if the Allison would help my cause. Whats this you speak of auxiliary overdrive? i've heard of them but lack any knowledge.

[DmaxMaverick]

The aux. OD, or aux. tranny, is a gearbox that mounts behind the original tranny. Like a second auto tranny behind the tranny. They work, and work well, but cost as much as most trannies. You can find them for less, but they usually aren't worth it (worn out, needing overhaul).

A well built 700R4 will work well if it's done right. If you need advice in that department, Robyn knows them inside and out, especially when it comes to the right upgrades. A good transmission, IMO, as long as you work within its limits.

[Robyn]

I agree 100% with Maverick
This box even though its a 4 speed will not give you the OD that the new Allisons do.
The new stuff however need a computer to run.

A very healthy built turbo 700R4 (Needs major upgrades to be fit for duty) would give you the low first gear and the tall OD for cruising.

Thanks Maverick
The 700 needs many upgrades but will hold a 6.2 or even a 6.5 if done right.
I wrote a post on this subject in the drive train forum (Its a sticky up towards the top of the listings)

The biggy with the 700 is that the internal parts are small and need the best stuff the aftermarket has to offer to make them fit.

Or as mentioned an add on Overdrive

Have fun

Robyn

[GATVILLE]

i appreciate the responses, ill start looking for a 700r4 core soon.

[DmaxMaverick]

Make sure the case is a "K" casting. A large K will be raised on the casting right side. This is the preferred HD case.