speedometer

just got my jeep back from the frame rack and had the guy throw in a new transfer case(NP231). now my speedometer is acting more like a tachometer. when i accelerate it reads up to 80mph and settles at around 55.... and i'll only be going around 35.

what gives? speedo gear?

Sounds like the guy didn't index the speedo drive gear to the transfer case. There is a procedure is the FSM for doing this, based on the number of teeth on the gear. If the guy just threw it in and tightened down the lock nut, it's probably skipping teeth.

I had the same problem last month with my speedo reading incorrectly on my 97.
My Jeep also wouldn't accelerate correctly because the speedo and computer were seeing higher than actual speeds (jumping needle) and this wouldn't allow a downshift out of overdrive. The Jeep would just hesitate as the computer tried for a downshift for power but the trans wouldn't allow it because it thought the Jeep was doing 95+ mph.
Mine turned out to be a bad speed sensor. I had to unplug the speed sensor at the t-case just so I could get up the freeway onramp and up traffic speed on my way to work. This will trigger the check engine light after several miles but it did allow for normal driving, shifting & acceleration.
After I figured out it was my speed sensor (I thought it was a bad connection at first) I went to the dealership and picked up a new one for 35 bucks. They had 5 in stock & the service dept guys said it's a fairly common problem. The new part looks slightly different and comes with a newer style pigtail connector that won't plug into the stock pigtail so you'll have to splice it in.
The new sensor works great and the computer will reset the check engine light after a day or two while it receives data from the reattached speed sensor.

thanks guys, i'm glad to hear those responses. it doesn't sound to me as if its gonna be to expensive to fix. i'll go to the jeep stealership manana and pick up a new speedo gear(i need to reset it anyways, i'm going to 33's) and probably a new sensor. thanks again.