94 suburban shift prob

i have a 94 chev suburban the prob is when im driving at about 40 mph its not shifting into the gear its supposed to be in like overdrive not kicking in or somthing any ideas or hints on what to check would be a great help not sure around same time this happenn my steareo was stollen and my alarmfor my truck would not go off could it be electrical or a wire that might have been disconected:banghead: any help or ideas

i have a 94 chev suburban the prob is when im driving at about 40 mph its not shifting into the gear its supposed to be in like overdrive not kicking in or somthing any ideas or hints on what to check would be a great help not sure around same time this happenn my steareo was stollen and my alarmfor my truck would not go off could it be electrical or a wire that might have been disconected:banghead: any help or ideas
How is all other gears?
Mileage and transmission and fluid level and condition and what service has it had?
Is engine running good?
Any check engine lights or engine codes?

It needs to be put on a transmission/engine capable scanner and transmission data read out and codes checked.
Post back any transmission and engine codes?

Make sure that your shift linkage wasn't damaged in your recent escapades - maybe it's not really in the gear you think it is, like pointing to where you want it, but not really in that gear.

check for proper battery voltage tranny will not shift if voltage is low p.s. had same problem changed batteries problem went away i have 2 mine is a deisel

i have a 94 chev suburban the prob is when im driving at about 40 mph its not shifting into the gear its supposed to be in like overdrive not kicking in or somthing any ideas or hints on what to check would be a great help not sure around same time this happenn my steareo was stollen and my alarmfor my truck would not go off could it be electrical or a wire that might have been disconected:banghead: any help or ideas

You need to be a little more specific. I need to know exactly what gear its not hitting. Drive it and count the shifts. Believe me, it makes a difference. You could be having problems with the converter clutch, the 3-4 clutches or even the band servo. I cant narrow it down unless I have more specifics.


transman

I would start with the basics fluid level,my problem started pretty much the same way since the tranny is computer controlled the battery voltage is important to every sensor on the whole vehicle so thats what I did changed the batteries and the problem went away also check for loose wires and or loose grounds once again once i tightened up the grounds other problems dissappeared its called preventative maintenance loose wires and or improper voltage=wrong signal to ECM Basically the ECM doesent know what to do therefore sensors dont know what to do causing the vehicle to run abnormally so i would start with the basics before you spend the money on a dealer or pricey repair that might send you back to square one