2001 tahoe not going into Reverse or OD

I have a problem with my 2001 Tahoe. When i put it into reverse the tranny will not engage. I can get it into drive but it will only shift through 1, 2, and 3 but not OD. Can't back out of the garage and have to go to work tonight. Any ideas?? :banghead:

I have exactly the same problem with my 2001 Tahoe, with only 34,265 miles. Also a ABS pump constantly running.
Have you resolved the problem ? What was wrong ? Please help.

I have believe i have the same problem as you,(see thread below yours) i have found a Tech Service Bullietin: 00-07-30-022 NOV 00 A/T - 4L60E No Reverse, 2nd, or 4th Gears. but i dont have access to it for the specifics, this happened to me last night, but from what i have found it might be the Sun-shell gear failing, i hope its not cause this means a transmission rebuild. does you car shift hard from 1st to next gear when in D?

I had the same problem - no reverse and lack of a couple other gears on a 99 Tahoe with less than 50k miles. The cause was a broken/defective sun shell gear found during the transmission rebuild.