Hi there, I’m having a weird problem with my 88 3.9 Dakota 4x4 (31RH?) where it will start up and shift fine and have good oil pressure cold, but once warmed up it will start shifting hard and clunky (Sometimes) and it gets really bad when I put it in reverse and 4lo for some reason—oil pressure will struggle and it'll try to die on me… and if I shift out of reverse it will surge and SLAM into gear, and oil pressure will come back.

The brakes also get super hard when it’s choking in reverse. I replaced the one transmission speed sensor I could find (two inputs, one for speedo cable) and the oil pressure sensor, which both helped, but the issue persists.

Any thoughts or suggestions? It definitely feels worrying… I was told the transmission was rebuilt and the TC replaced before I got hold of it just for the record.

Also this thing was sitting for yeeears, I know from experience on older cars that I probably want to replace some sensors just out of caution before assuming the worst. Is there a tachometer or another speed sensor somewhere? If you have any thoughts on safe bets to improve performance I’d appreciate them.

Thanks in advance!

 

Read through the FAQ section. Find out if there are any codes. I replaced all of the sensors when I bought mine just to be sure they were all new, it was over 20 years old then. But I get it you want to know if there is something big wrong.