PLEASE HELP, transmission shifts too soon

[scotty123]

Just recently bought a 96 jeep cherokee with a blown motor. Then bought a 98 wreck with a good motor. Decided to just swap the motor and transmission since it looked so easy to get out in one piece. Well, had to change a few plugs on the transmission, and use the old carb from the 96 on the 98 in order for the TPS to plug in, had to remove one of the plugs from the old transmission and splice in onto the new, the wires were the same count and color so didn't see a problem there. Once swap was completed, the engine fired up, no problem. Tried the first test drive and it goes into all the gears fine, into 4wd fine, reverse fine, just shifts into Overdrive way too soon! and will not downshift if you mash the gas.

Any help would be greatly appreciated! Also, have tons of spare parts from the 98 and the left over transmission from the 96,

thanks,

 

[Bounty__Hunter]

Make sure the TV cable to the transmission is adjusted properly, and the throttle position sensor. The TPS is best adjusted with a scan tool hooked up to the OBDII port.

 

[scotty123]

Thanks for the reply, which one is the TV cable? Also, this jeep has sit for about a year or two since the engine blew, I had to swap the throttle body out since TPS plug on the 98 engine did not match the wiring harness in the 96 jeep. I'm not sure if this means anything, because the engine starts right up and idles nice, takes fuel great, and runs fine in reverse, just shifts imediately into OD from forward take off?

thanks again,

 

[Bounty__Hunter]

It's a cable attached to the TB linkage and has a black button you can press to adjust the cable. You'll need the adjustment procedure.

 

[scotty123]

Ok,

I put a brand new TPS sensor on the throttle body, adjusted the TV cable and it is still doing the same thing. I bought the Haynes manual and followed the procedures for TV adjustement and TPS replacement, still no good!

The trouble again, the jeep takes of fine in D until about 10mph then shifts immediately into OD, way too soon! I can't find any hints in the Haynes manual about this situation, has anyone got any ideas????????????

thanks

 

[JEEPNXJ96]

check your splices that you made and make sure they are good. sounds like you may have a faulty solenoid in the transmission. if the splices are good drop the pan and check the solenoids. to check use a multimeter and ohm the solenoids,they should all ohm out the same,if there is a lot of variation betwwen the three they all need replaced. they are not cheap,about 300 bucks for all three so use the solenoids from the other transmission if they are good. my bet is probably the wiring to the solenoids though that is bad.