Drivetrain upgrade

gandolphxx · April 29, 2002

It is time to work on the drivetrain of the beast - the 2500 Avalanche has the heavy duty version of the 4L80E [RPO:MN8], also known as the 4L85E - a transmission that has been around for a long time. This version has been beefed up to mate with the 8.1L V8 and is quite capable - and should be able to do better.

All of this can be done to the 4L60E that is standard on the 1500 so don't feel left out, come join the fun. This also applies to the 4L65E that is in some of the 2002 models.

Here are some of the things to extend life, get better performance, and get off the line faster.

1. Mag-Hytec Get a deeper pan for the transmission, more fluid, better heat absorption. The 4x4's already have this.

2. Get a transmision aux cooler if you dont have one, and of course a temp gauge[cluster swap for the 1500]. GM makes one the will fit right on, Flex-a-Lite, CoolPak, B&M, etc.

3. Consider a larger rear differential cover Mag-Hytec to allow more fluid and easier maintenance. Towers take note - this is your point of failure.

And now for the fun stuff:

4. Get an upgraded torque converter, increase the stall speed from 1600 - 1800 RPM to 2600 RPM, beef it up with Kevlar clutches. This will reduce the drop in RPM that occurs with the stock TC to provide slow, smooth shifts for your great grandmother. Don't go above 2600 if you intend to tow.

Yank writeup

Another TC writeup

Precision Industries Vigalante

TCI torque converters

These are not cheap and the install price typically equals the cost of the converter. While you are doing the converter, it is a good time to re-program your transmission - this will firm up the shift intervals and improve the life - note, this will remove the sluggish shift that comes stock, more like snapping the clutch.

Transgo re-programmer <-- read this for education.

Jet Performance Power Shift

And for the real diehard there is always the Trans brake, this is probably overkill.

Well thats what I know, still learning, am sure others have better ideas and thoughts, jump in.

UPDATE: The drivetrain is now beefed up.

1. The torque converter has been changed to a 2600 stall, closer to 2800 with the Whipple chasing it. Clutches changed to Kevlar and the back plate replaced and strengthened. Similar to a Yank 2600HD+.

2. The transgo re-program kit has been installed and broken in - wow, this baby shifts like a stick Vette now - 1st to 2nd will scare your g/f or boss. The shifts are like "right now!".

It drives smoother, quicker and faster. I am impressed and delighted, cost less than I expected and exceeded my expectations.

Need to wire up the SCU2000 [$25 on Ebay] and still looking at the Mag-Hytec, which I think will just fit.

Cheers