4L60 to 4L80E

[nape]

HEEELLLP,
I purchased a 4L80E without realizing what it was. (thought it was 4L60) what do I need to make this work in my 90 Sub. behind a 6.2 and where can I get it? Or is it just to expensive?
thanks Nape

[britannic]

You'll need an aftermarket computer or find some way to adapt and OEM one to get the shifts working. It's great tranny and well worth getting it working properly.

[Randee of the Redwoods]

Jeg's sells a TCI 4l80e stand alone controller, but it's pricy. Allows for the install into any vehicle and is user programable. Comes with it's own harness. Other than that, you'll need a 4l80e harness and factory ecm that can control it. Lots of wiring will need to be done to get the electronic tranny running in a non-ecm truck.

[gmctd]

'91 trucks, incl Subs, had 4L80E option - all you need is stand-alone trans computer, trans harness, tps from inj pump, VSSB,'91 Sub quartz speedo, and driveshaft.

Should be able to nab all that for around 500 bucks from your local boneyard.

Do a "search" on all three member forums for more info

[nape]

Is there anyway to make it shift without a computer? Can I convert it over to manual shift?

Budjet wooooooees
Wayne

[nape]

What are the "all three memeber forums"?
Wayne

[gmctd]

My apologies, Nape - I overlooked your responses.

No practical way to shift the 4L80E without the computer. It's a small package, used from '91 to '94, and maybe later in vans and P-chassis.
The Torque convertor circuit is a bear, and the aftermarket guys have not been successful in doing a "box".

6.5L Turbo Diesel, 6.2L, and Member's forums are where I was suggesting doing the 'searches'. I think was some stuff on Dr. Lee's Forum, also, but it got wiped during the Great Crash of Ought Three.

[BC Clark]

Something to keep in mind with a 4L80 swap. The 4l60/700r-4 were esentially derived from the TH-350. As such they have a very low first gear. It got even lower with the jump from the TH-350 to the 700R-4. Current specs list the 4L60/65E at 3.06. The 4L80/85 were derived from the TH-400 (a great tranny) and carry a 2.48 first gear. The 4l60 therefore provides a 23% lower first gear and accordingly a 23% increase in rear wheel torque. This is why a lot of hot rodders today build up 700R-4s and 4L60s. There are many places that do those builds now.

I personally think the 700R-4 got a bad rap because GM folks were used to their bullet proof TH-400s when the dawn of high gas prices and light O.D. transmissions came. Compared to the reliability of the 4 speed O.D.s from Ford and Chrysler in the 80's and you might call it a great transmission. The 4L60/65s are smoother and better.

All that said, the 4L80/85s are the strongest things out there besides the big Allison. If you don't have a 2.73 rear end and like leaving your coffee on the dash it'll be great and maybe the last thing you ever do between the bellhousing and transfercase.

[nape]

Thanks guys I have a line on a computer and wiring harness and that might just cure my problems. The 90 Sub has the electronic Speedo and I think maybe the engine speed sensor.(it has something electric hooked to the vacum pump) I will still look for a computer, junk yards around here are pretty reasonable.

Nape

82, 83, 87, 90 Subs with 6.2, 2(86) military Chevys with 6.2, one Hicube 87 6.2, (3) 6.5 pull outs for crate engines, and just purchased an 84 Sub with 117 K on crate engine with turbo and monster 700r4