In this multi-part write-up we will follow some simple items you can do to your 4L60E transmission so it can work harder for you. As always when ever working on or under a vehicle it is best to make safety first. Please take caution to secure the vehicle from being a hazard from yourself and others. All suggestions in this article are to be used at your own risk and are not designed to "fix" transmission problems.

The victim, I mean subject, is a 1998 Chevy Tahoe LT with a 5.7L engine and 4L60E transmission (of course). This vehicle is our family abuse vehicle having to be able to haul ourselves, kids, dogs and a 25' Coachman Catalina... sometimes all at the same time!

How did we find this out? We took a trip to California towing our 25' Catalina, burdened with 3 adults, 2 dogs and all the staples needed to make the trip. We found by the next to last day from home that we started to have some transmission problems. The transmission would be fine on flat open roads, but as soon as we hit a grade with all of that weight. The torque converter would unlock and the transmission would start slipping. We babied it home... unhooked the camper and things returned to normal- couple days later I changed the fluid and it was burnt (keep in mind there wasn't even 10,000 miles on this fluid). That is when I started looking on the internet and finding similar complaints from all types of GM owners from Trucks (mostly 1500's), to Tahoes and Suburbans and even some Firebird and Camaro owners.

Temperature gauge installation: Installation of a temperature gauge so you can physically see how much the transmission fluid is heating up. This is to also help establish a base line temperature of the transmission and monitor how different modifications affect the operating temperature.

Addition of Auxiliary Transmission cooler: Despite this vehicle having the tow package and a factory cooler, it wasn't enough to keep this transmission cool while working. So we will be adding an additional transmission cooler to circulate fluid through. In this case we purchased a B&M Stacked Plate Transmission cooler rated at 24,000 GVW.

Deeper Transmission Pan: Another way to fight heat... this pan adds approximately 3 Quarts of fluid. Extra fluid means there is more fluid to dissipate heat and in turn to circulate out of the transmission to cool off. Deeper transmission pans are available from a variety of manufacturers. Typically made from steel or aluminum with different styles including finned or smooth. For this write-up we've purchased a Summit Aluminum Transmission pan which includes a drain plug for easier fluid changes.

UPDATE: We have unfortunately sold the Tahoe for a Diesel Tow Rig- I've left the below explanations hopefully to help people understand what they do and their purpose. A lot of research went into the issues we had with our Tahoe but great improvements can be made with a minimal amount of money and some wrenching. Getting the transmission temps down to reasonable levels along helped the longevity and performance of this transmission.

1st to 2nd shift Servo replacement: This servo is easy to get to- being that it is accessible from the outside of the transmission, so I don't have to keep breaking open the pan over and over. This will be the first thing that actually improves the shift. (NOTE: This does not change the shift point just the actual duration of the shift). By speeding up the duration of the shift there is less slippage and in turn less heat, this modification also improves how much the servo holds the shift band (larger surface area of the servo). There are two types of servos typically swapped in- one being a stock corvette servo, the other an aftermarket or billet servo with a larger surface area (JET is one example of a manufacturer of these servos).

Shift kit: This will provide stronger, quicker shifts through out the transmission bands- again to fight heat and transmission slippage. This is another product that there are a variety of companies making kits for the 4L60E and of course all claim to be the best. This will also be the hardest part to install... the transmission doesn't need to be un-installed from the vehicle, but you will have to drop the transmission pan and remove the shift body and plate. While the transmission is open this is also a good time to bump up the force motor which controls fluid through the transmission (a requirement in some shift kits)

3rd to 4th shift Servo replacement: This is also best in done in conjunction with the shift kit since you will already have the pan off. This again is much like the 1st to 2nd shift servo replacement with the same purpose and again you can either replace it with a Corvette servo or purchase an after market servo designed to do the same thing- firm up the shit and hold the shift band tighter.

Biggest temp. spike was to 195 with A/C cranked and no air flowing through coolers, sitting in bumper to bumper traffic while towing.