Help Transmission troubles!!!!

[RWF1970]

My 98 Sierra 4l60e shifts fine in 1st to 2nd but when it goes to shift to 3rd it idles way up and will not shift but the idle remains high till I put it in park. Then it's fine. Even if I put it in neutral while it's idled up it will not quit so I thought time for a rebuild. So I bought a rebuilt one and put it in and having the exact same problem. Any ideas???

[Swimmer8366]

Time to rebuild Transmission

 

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[RWF1970]

This is the rebuilt one. I took the old one out because it was doing the exact same thing,put the new one in and still have the problem

[Heavy 5.7]

Any ideas???

For what it's worth. you're not alone:

http://www.gm-trucks.com/forums/topic/197087-04-silverado-transmission-slip/

[Chevygrl]

Did you replace anything else when you put in the new transmission?

[Chevygrl]

If not I'd go ahead with your torque converter, and solenoids especially shift solenoids.

[Dnt]

Will be hard to diagnose without a code reader take it to your local trans shop and have them run an analysis. report back their diagnosis and we will evaluate it haha