There are many mechanical sounds that have a certain way of crawling right into your head and releasing thoughts of dread and dismay. Those kinds of sounds signify that your day, week, or possibly month is in complete ruin. There seems to be a direct correlation between the emanating sounds and your wallet. It’s like they’re somehow connected to each other, causing your credit cards and hundred dollar bills to shake uncontrollably. We felt that exact wallet shake and feelings of dread when our ’02 Chevy Avalanche began to show signs of finally calling it quits. Trying to get moving from a stop was an exercise in frustration as the engine would rev, but the transmission wouldn’t allow much forward momentum. After a week of slipping, the 4L60E had enough of our abuse and decided to leave the SUT stranded awaiting a tow truck to come to the rescue.
You may remember the truck from a previous issue as we pulled the high-mileage (read worn-out) 5.3L from its engine bay and replaced it with a new LS327 crate engine from GM Performance Parts. Things have gone swimmingly since then, but mileage takes its toll on parts and our original automatic transmission was knocking on 160,000 miles. To replace our ailing unit we called the crew at Gearstar transmissions in Akron, Ohio, and ordered the company’s Level Two 4L60E. In it, Gearstar fits all new wiring and solenoids, a Corvette servo designed for more power, high capacity 10-vane pump, better bands for the shift drums, a TransGo shift recalibration, and many other parts to ensure its transmission lives up to the reputation Gearstar has set. It even comes with a furnace-brazed torque converter for stalls between 2,200 and 2,400 rpm. Rated for duties up to 450 hp and 425 lb-ft of torque, the Gearstar 4L60E will be a perfect complement to the 327hp LS327 we nestled under the hood. Doing the transmission two-step while we snapped the picks was The Transmission House in Covina, California. Once up on the vehicle lift, the guys handled the swap in no time at all and made everything go so easily.
From The Driver Seat
The Transmission House did a great job of handling the swap like the professionals they are, but keep in mind, this is an install you don’t have to be afraid to do in your own driveway. With all the right tools and equipment, the job went smooth as silk. Once out on the road, the slightly firmer shift was barely noticeable under light throttle conditions and it was a nice change to step on the throttle and have the truck move ahead with the authority we always thought it should have. Between the new engine and transmission, our truck should last another 150,000 miles with proper maintenance. One item we didn’t show being installed was the Hayden auxiliary cooler. Heat is the number one cause of failures in automatic transmissions, which is why Gearstar ships all of its units with a Hayden box of goodies. When you do your transmission swap, remember to flush all the lines and install an auxiliary cooler to protect your investment and extend its life.