- Dec 4, 2011
- 12,927
Skip to the bottom if you don't want the back story.
Technical Stuff and Background:
I've had a bit of a history with the GM 4L60E transmission and dealing with some of the shortfalls of it. Over all, it is a good transmission, but it has a few weak points. A semi-common issue with the 4L60E is the TCC (Torque Converter Clutch) valve bore gets worn because the TCC valve is PWM (Pulse Width Modulated). This allows for a nice, soft engagement of the TCC lock, but it can result in the valve vibrating in the bore and wearing it. Enough of this wear and the TCC valve doesn't seal right - particularly when the fluid is warm - and the converter fails to lock, or locks, then unlocks, and repeats. The TCC not locking results in higher engine RPM, which burns more fuel, but also results in elevated transmission fluid temperatures, which can lead to even more issues such as bands burning up etc. This SHOULD throw a code P1870 "Transmission component slipping" but it doesn't always. One side effect is the computer realizes something isn't right, and then it starts to slam the 1-2 shift extremely hard via jacking the line pressures way up in an attempt to compensate for the issue.
I battled this problem years ago in my old 1998 Camaro that had the 4L60E, until it got to the point of neck-snapping 1-2 shifts and still not being able to figure it out. I ran across the Transgo SK-4L60E shift kit that while I still didn't have that code I was having a lot of the other symptoms. As a last ditch effort hoping that I wouldn't have to replace/rebuild the transmission, I bought that kit. Well, then I found I needed other parts because seals don't come apart cleanly, etc, but after getting it all back together, IT WORKED. No more slammed shifts, no more burnt fluid, TCC locked perfectly every time. The TCC lock instead of a mushy "slip" into lock feels like it shifts into a 5th gear now. That transmission is still running by the way in my current 1999 Camaro, which is cammed, that I drive somewhat aggressively at times, and it hasn't missed a beat. Perfect shifts every time. That transmission has over 170k on it, by the way.
I installed the kit (with a couple other goodies, details below) in my 02 Trailblazer when it had 120k miles on it. At the time I bought it, the fluid had never been changed, and it was very, very dark. Not burned, but past due. At the time of demise of the Trailblazer, it had 215k on it, shifted perfect all day every day, and the fluid was still a nice red color. Nope, aside from the fluid flush I did at 120k using the May03LT method, I hadn't touched the fluid (I know, shame on me, but it was a bit of an experiment too). I'd say that's a good proof! I put the same kit in my current 2007 Silverado 1500 when I bought it a couple years ago.
TL;DR - The Kit
OK so you don't care about the whys or whats, you just want to make your 4L60E a little more durable and prevent issues down the road. Here's the goods.
An ebay seller ctpowertrain has a combo kit that includes basically everything you need, plus some, aside from a new filter and fluid. Very handy. Pay attention to the years as there were minor changes GM made to the 4L60E transmission. They have kits for the pre-96 years too, but because our trucks only go back to 2002 I didn't bother linking those.
1996-2006
http://www.ebay.com/itm/4L60E-4L65E...ash=item3f1166b953:g:WDkAAOSwpDdVeOGx&vxp=mtr
2007-2008
http://www.ebay.com/itm/4L60E-4L65E...ash=item43de1b41af:g:JakAAOSwrklVeOJG&vxp=mtr
As a side note, I have always used the Valvoline Max Life red jug Dex/Merc "high mileage" fluid.
Technical Stuff and Background:
I've had a bit of a history with the GM 4L60E transmission and dealing with some of the shortfalls of it. Over all, it is a good transmission, but it has a few weak points. A semi-common issue with the 4L60E is the TCC (Torque Converter Clutch) valve bore gets worn because the TCC valve is PWM (Pulse Width Modulated). This allows for a nice, soft engagement of the TCC lock, but it can result in the valve vibrating in the bore and wearing it. Enough of this wear and the TCC valve doesn't seal right - particularly when the fluid is warm - and the converter fails to lock, or locks, then unlocks, and repeats. The TCC not locking results in higher engine RPM, which burns more fuel, but also results in elevated transmission fluid temperatures, which can lead to even more issues such as bands burning up etc. This SHOULD throw a code P1870 "Transmission component slipping" but it doesn't always. One side effect is the computer realizes something isn't right, and then it starts to slam the 1-2 shift extremely hard via jacking the line pressures way up in an attempt to compensate for the issue.
I battled this problem years ago in my old 1998 Camaro that had the 4L60E, until it got to the point of neck-snapping 1-2 shifts and still not being able to figure it out. I ran across the Transgo SK-4L60E shift kit that while I still didn't have that code I was having a lot of the other symptoms. As a last ditch effort hoping that I wouldn't have to replace/rebuild the transmission, I bought that kit. Well, then I found I needed other parts because seals don't come apart cleanly, etc, but after getting it all back together, IT WORKED. No more slammed shifts, no more burnt fluid, TCC locked perfectly every time. The TCC lock instead of a mushy "slip" into lock feels like it shifts into a 5th gear now. That transmission is still running by the way in my current 1999 Camaro, which is cammed, that I drive somewhat aggressively at times, and it hasn't missed a beat. Perfect shifts every time. That transmission has over 170k on it, by the way.
I installed the kit (with a couple other goodies, details below) in my 02 Trailblazer when it had 120k miles on it. At the time I bought it, the fluid had never been changed, and it was very, very dark. Not burned, but past due. At the time of demise of the Trailblazer, it had 215k on it, shifted perfect all day every day, and the fluid was still a nice red color. Nope, aside from the fluid flush I did at 120k using the May03LT method, I hadn't touched the fluid (I know, shame on me, but it was a bit of an experiment too). I'd say that's a good proof! I put the same kit in my current 2007 Silverado 1500 when I bought it a couple years ago.
TL;DR - The Kit
OK so you don't care about the whys or whats, you just want to make your 4L60E a little more durable and prevent issues down the road. Here's the goods.
An ebay seller ctpowertrain has a combo kit that includes basically everything you need, plus some, aside from a new filter and fluid. Very handy. Pay attention to the years as there were minor changes GM made to the 4L60E transmission. They have kits for the pre-96 years too, but because our trucks only go back to 2002 I didn't bother linking those.
1996-2006
http://www.ebay.com/itm/4L60E-4L65E...ash=item3f1166b953:g:WDkAAOSwpDdVeOGx&vxp=mtr
2007-2008
http://www.ebay.com/itm/4L60E-4L65E...ash=item43de1b41af:g:JakAAOSwrklVeOJG&vxp=mtr
As a side note, I have always used the Valvoline Max Life red jug Dex/Merc "high mileage" fluid.