ack transmission trouble

[mike_flemming]

Well, ive had my lumina for about 6 months (148,000 KM) and a little while after i got it it started shifting harder into second gear. Il be driving (happends driving fast and slow) and when it shifts into second it slips a bit. Its like the shoft is delayed and then it kicks in. It happends fast though, so theres no huge rpm jump or anything and from first two second is the only time it happends....any suggestions as to what this is?? ( ive had a flush and fluid change and it diddnt fix it) please????

[Blue Bowtie]

What year Lumina? At least up to 1997, the transmission used still had a vacuum modulator to control line pressure. You may want to check the vacuum hose to the modulator.

[jeffcoslacker]

Originally Posted by Blue Bowtie

What year Lumina? At least up to 1997, the transmission used still had a vacuum modulator to control line pressure. You may want to check the vacuum hose to the modulator.

Ding Ding Ding....we have a winner

[mike_flemming]

so where do i go from here? is this something i can do myself? or is it a stressfull expensive undertaking...and is it ok to keep driving like this ir is it damageing it further? info?

[Blue Bowtie]

The vacuum modulator is located on the front of the transmission. It is visible from the top, toward the left (driver's) side of the vehicle. There should be a rubber vacuum line connected to it, and the other end of the line should be connected to a vacuum port on the intake plenum. You can remove teh vacuum line and check for the presence of vacuum with the engine idling.

If there is fluid leakage into the vacuum hose, the modulator has failed. Even if there is no fluid present in the vacuum hose, the modulator could have problems. They are a common failure point on the 4T60 and 4T60E. Replacing one is relatively easy, even if access is limited. A new aftermarket replacement can usually be found for about $25, but diagnose the problem before replacing anything.

EDIT: - That "4L60/4L60E" should have been "4T60/4T60E" - I got my longitudal and transaxle designations all confuzled in the wee hours. (Nice catch, Max!)

[richtazz]

The 4T60-E trans used in your car (95 according to your profile) is a hybrid. It uses a vacuum modulator, but also has electronic shift solenoids. I would try shifting the car manually. If it shifts smooth manually, then the vacuum modulator is probably bad, or it's getting a bad vacuum signal from a cracked or broken vacuum line. If it still shifts harshly manually, then I would say the shift solenoid in the valve body is the issue.

[mike_flemming]

i looked quickly today and couldnt spot this vacume line..any pointers as to where it is exactly..or whats near it? and what am i looking for..a crack or kink or something?