Engine/Transmission (1994 - 1998) Need help with Auto

[TKemper]

My brother in-law just got a 94 2500 auto 4x4. I'm the lucky one who gets to fix it, so I went and picked it up tonight. On the ride home it shifted from 1st to 2nd fine, but wouldn't shift into 3rd under medium to full throttle. I had to let off almost completely, then it would go into 3rd. Under light to med throttle 3rd was hunting for 4th, but actually felt like neutral, then would drop into 2nd, it was shifting all over the place. It never went into 4th or lock up. I played with the overdrive button, but it didn't do anything. My 97 is a 5 spd, so this auto is new to me. Could the TPS or cable adjustment cause this. Maybe a vacuum leak? This is a 47rh. Any suggestions on things I should check would be of great help. Maybe it's just toasted... ..... it's got 125k on it. TIA Todd

 

[TKemper]

Thanks Bob, I can see I'll be up late doing research.

 

[jeepcjsrule]

That sounds just like the problems i was having with my truck right before i replaced my tps it has been shifting fine since i have 150,000 right know on my stock transmission with no problems yet.