4L60E Shifting Problem

[1998Z71]

Good Morning GM Tech,

 

I know this topic has been covered before, but I haven't seen anyone post their results.

 

I have a 98 K1500 Z71, 350 with the 4L60E trans, 148,000 miles. The problem I am having is it that when it shifts from 3rd to OD, it seems to surge or slip and feels like it shifts back and forth from 3rd to OD. It seems to be worse when cold, but will still occasionally do it when up to operating temp. The speed that this happens at is between 45 and 50 mph. I drive like their is an egg between my foot and the gas peddle, this is when it is most noticable. If I give it more throttle, and accelerate through the 45 to 50 mph range, it won't do it.

 

Any suggestions or guidance you have would be appreciated. Thanks.

[GM-Tech]

This is probably TCC, not 3/4 shifting. Someone needs to drive this with a scanner on it so they can monitor what's happening.

[1998Z71]

Thanks for the quick reply. As soon as the funds allow, I'll have to schedule an appointment at the dealership. Just for my own information, what could be a possible cause?

[GM-Tech]

  Just for my own information, what could be a possible cause?

 

Valve body. Pretty common, however, I would expect a code to be set for this.

[1998Z71]

Once again, thanks for the quick reply. The only time the SES light has come on was for two oxygen sensors and for the gas cap being loose. I'll have to let the dealership take care of this one.

[1998Z71]

Just had it in to be looked at. The seal between the transfer case and transmission failed and was allowing fluid from the transmission to overfill the transfer case, leaving the transmission low. Having the seal replaced, trans flushed, and filter changed. Service Manager at the dealer said this should cure the problem.