jay seidel

I have a 1996 zj that has no overdrive and there is no codes in the computer. has anyone here ever experienced this. thank you

SeriousOffroad

Try lifting the brake pedal with your left foot while at highway speed. You're TCC Signal goes through the brake switch.
Post up your results.

jay seidel

Ok , i'll try that, thank you for your quick reply

gs69350

Had similar issue with my jeep. Took over 100 miles before a code came on. The governor and od solenoids are a common failure. They are relatively easy to replace though.

jay seidel

lifting the brake pedal didn't work. Prevoiusly the jeep wasn't shifting at all and i had 3 computer codes so I replaced both of the selonoids and the wiring harness and now im shifting 1st thru 3rd but have no over drive.

gs69350

Not 100% but could be a broken 3-4 accumulator shift spring. $2 part.

jnicewan

Almost all of the electronic parts of 4th gear usually set DTC's when they fail. Since you have a way to check for codes, do you have a way to monitor eng/trans live data? If so check all the sensors and look for something out of the norm, like ECT sensor indicating low, or trans fluid temp low/high If you manually cancel O/D with the switch, do you get T/C lock up in 3rd gear? T/C normally doesnt lock in 3rd, but it will only if you selected O/D off.

Try this, Drive your jeep up to the speeds in which you know it should be in O/D. Take you foot off the accel and see if you have engine braking or it just coasts freely. If it just coasts then I bet the O/D clutch has failed.

jay seidel

jnicewan, no it doesn't coast freely, it drops rpm's as if i did apply the brakes. gs69350, where is the 3-4 accumulator shift spring located? I dont know if this is related or not but when i do apply the brakes there is a clicking sound that coming from the passenger side dash and it also clicks when i turn the headlights off, the headlight will stay on when i 1st attempt to turn them off, 2nd attempt they turn off. Also the ABS light is on.

Also, i contacted the previous owner and he said he did replace the engine computer, with a computer without matching numbers from original before he replaced the transmission. He replaced blown tranny with junk yard tranny and drove it for about 7000 miles before it stopped shifting, and i purchased it not shifting thinking it was an easy selonoid fix.

gs69350

Sorry for the delay, was hoping to get on a PC and post a pic of where the spring is. But you can go on YouTube and search for 42re master solenoid replacement. There is a builder who posted a detailed video on the solenoids and step by step to replace. The 3-4 spring is part of the video.

purplegrocerygogetter

I have a 97 zj that was doing this, have you check you speed control sensor? Mine was leaking and causing it to not shift to OD, the RPMs were crazy! I thought my jeep had gotten possesed or something! After taking in to shop and being taken for a complete breakdown of my tranny because of the leak, which they never fixed... And around $1500 later a friend says did they check this? The speed control sensor? Aparently not because it still was crazy!! As for the headlights they should go off after 1 minute lol and the ABS light has to be a jeep thing my 95 and 97 both had the light on!

jay seidel

purplegrocerygogetter, didn't you have a check engine light for the speed sensor control? Is that the sensor that is on the drivers side of the transfer case?

purplegrocerygogetter

Nope, never threw a code, infact even had it hooked up to a computer and it told me my tranny was great, and yes drivers side. I wanna say by 4 wheel drive

jay seidel

Thanks for everyones input and sorry i didn't respond earlier.

purplegrocerygogetter, i removed the speed sensor but no transmission fluid ran out, maybe the transfer case is low on tranny fluid. should there be tranny fluid coming out?

jnicewan, i'm going to try to rule out electronic possibilities first before dropping the pan & valve body again. but if it comes to that I'll check out that spring.

purplegrocerygogetter

No, no fluid came out, mine shorting out, have you tried manually shifting it into each gear to see if it engages? Try that and if it does then I do believe its going to be the sensor, or elec. if not it the trans itself.

jnicewan

If its has engine braking and not freewheeling when letting off the gas tells me that the O/D clutch is still good and not failed. The spring you are probably asking about is the 3-4 accumulator spring. It is mounted to the lower valve body in a little housing about the size of a smaller pill bottle, on the opposite side of the 2 solenoids. The lower valve body contains all the functions for the 3-4 shifting and T/C lock up, along with the T/C and O/D shift solenoid pack.

I'm not sure what could happen if the 3-4 accumulator spring breaks, its function is to soften the 3-4 shifts, you would think if it broke you would get a harsh 3-4 shift but it could have allowed the 3-4 piston to over-travel and leak pressure. The speed sensor for the trans (output shaft speed sensor) is actually mounted on the O/D housing on the lower drivers side, its right behind the pan and faces downward at an angle. I doubt you have a problem with this sensor because it would affect all upshifts and cause a lack of upshifts. The speed sensor on the t-case (veh speed/distance sensor) is mounted on the rear of the t-case output housing. Its function is for veh speed info.

You never answered if you get T/C lock up in 3rd gear when having the O/D switch cancelled? You said you replaced 2 solenoids in the trans for a no shifting concern, were these the gov pressure sensor and transducer, or the T/C and O/D solenoids?