4l60e trans 1999 gmc suburban?

[Robert]

1999 suburban cruzing speed sometimes rps jump up 200 rps and then back down does not do it all the time somebody said thats the convetor locking up

 

[Molson02536]

Yes that is the converter lock up, it's common for the boost valve to go bad and should be replaced every 60,000 miles. It's around $50.00 and can be replaced the same time you service the transmission. The boost valve weakens, causing the transmission fluid pressure to drop. It's the transmission fluid that keeps the pressure on the clutch pack and lock up the torque converter. To improve your transmission, these is just a few simple things you can replace. Replace the 1-2 Servo which can be done without dropping the oil pan, and replace the boost valve with the boost valve used in a corvette. This will give you a more aggressive shift, but will make your transmission last a lift time. Did that to my 4L60E transmission 2 weeks after i got my 96 jimmy and still doing good with over 365,000 miles. The cost with the transmission service should cost you just around $200.00 in total. the corvette boost valve and servo's should cost you around $50.00 each. Good luck and this should keep you from burn up your transmission.