So, Long story short, My 4th Gear disappeared right after I had my Transmission Tuned at Speed Inc. Speed Inc wouldn't give me so much as a refund and pretty much told me to **** off for thinking they had something to do with it. There was nothing I did to make my freshly rebuilt Trans lose 4th.

Anyways, I've been doing some research about it, and the only thing I could come up with is the 2-4 band is slipping and and that the servo seals may be bad. I already replaced all of my 3-4 clutchpacks, and replaced the 1-2 shift solenoid about a month ago.

Should I upgrade to a Corvette Servo and see if that fixes that? Can I swap out the servos or 2-4 band with the trans in the car or no?

Thanks guys,
MAYH3M

 

You already have the corvette servo.
Since you have second the band most likley is ok. I would look at the 4th servo.
It is unlikley that tuning caused and issue of this type.
I would however use a scanner to verify that the command is being given.
Also are you sure its 4th your missing and not lockup

 

Yeah, the computer is commanding 4th, it's just not shifting into 4th Gear.

and, I already have a corvette servo? I never upgraded it, unless Corvette Servo's come in all 4L60E's.

Thanks

 

It does not come in all 4l60e but does come in all v8 f body 4l60e

 

I see. Would a Problem with the Servo have anything to do with losing 4th gear? or the 2-4 band?

Thanks

 

tHE 4TH servo is what applied the band in 4th gear The 2-4 band is used in both 2nd and 4th gears but applied by two different servos.

 

So, any ideas on what it could be?

 

I would check out the 4th gear servo .

 

Okay, Can I check it with the Transmission in the car?