4L80E in a 6.5L turbo

[Dr. Jalkal]

Does this tranny have a lock-up converter when used in a 3/4 ton? When I touch the brake, I don't see the 200 rpm rise like in my 700R4 gas truck in 3rd or 4th gear.

Also,
Is there a decent tranny controller for this vehicle? 1998 Suburban Ls 2500. I'm also looking for a computer chip replacement for it. I'm trying to enhance performance when needed and get the economy when I don't.

To get better fuel economy, does it make more sense to change ring and pinion Or:
get an overdrive unit from gear vendors or dual range?


THanks,
Ron D.

[CleviteKid]

Hello, Dr. Jalkal,

Without the RPM rise, I am pretty sure you are not releasing a locked up converter.

With your 2WD truck, if you don't tow anything over 4000 lbs. on our flat Florida roads, I would recommend an axle ratio change to get better mileage.

For a Transmission controller, take a look at THE PCS PRODUCT. (http://www.powertraincontrolsolutions.com/content-4.html) More Power has done a little investigating of this product, and it looks pretty good, but this is NOT a www.TheDieselPage.com (http://www.TheDieselPage.com) endorsement.

I would contact John Kennedy (john@kennedydiesel.com) for your engine performance needs.

Dr. Lee :cool:

[moondoggie]

Good Day!

You might want to post your question on the 6.5L Turbo Diesel forum. Dr. Lee knows all, but he doesn't own a truck like yours - his is a 1984 C10 with probably the nicest 6.2 ever built. If you post in the 6.5L Turbo Diesel forum, there are a few thousand of us who will see your topic, & hopefully help. ;)

"Does this tranny have a lock-up converter when used in a 3/4 ton?" Yes.

"To get better fuel economy, does it make more sense to change ring and pinion Or: get an overdrive unit from gear vendors or dual range?" Try a search of the 6.5L Turbo Diesel forum - this has been gone over a number of times. Just be careful to do the math - it takes LOTS of miles to pay for mods by increasing fuel economy, although with prices previously headed towards $3/gallon, the payback was looking better than at $1.50.

Blessings!

[Scooby]

Our trucks with the 4L80E do have the lock up converters, but they do not unlock like the 700r4's did when tapping the brake pedal. Mine doesnt anyway. You can tell if it is locked up by driving about 60 mph, and pressing the accelerator some. You will see little or no rise in rpm till your speed goes up. If you do this at 30 mph,- before the convertor locks up, the rpms will immediately go up.