tranny problem?

ok so when i put my tranny into drive its like it barely engages into drive. at idle it wont go foward when im off the brake, and i have to give it a lot of gas to start moving. but when i put it into 1-2 it acts normal and has plenty get up and go. but when in 3 it does the same as what drive does. it wont engage into 4wd either, acts like its in neutral when its in 4low. there is plenty of fluid in the tranny and t-case. this is weird because about a week ago it drove fine. engaged into 4wd and drive fine. i havent driven it since then and today i went to work on it and its doing this.. any suggestions?

HO 4.0l aw4 np231

thanks

Do you have access to a factory service manual? In there, there is a section on basic tranny troubleshooting. It involves testing the throttle position sensor as it is directly involved in shifting characteristics, disconnecting the TCU as a way of determining if the problem is electrical or mechanical, etc.

So its acting like its trying to start off in 4th gear? This might be of help. http://www.transonline.com/transdigest/magazines/1997-10/Shift Pointers/index.html

does anyone have a pic of where the tcu is located? is it on the passenger side on the panel below the glove box?

Depends on the year. 96 and down you are correct, it's easiest to get to by dropping the lower half of the dashboard a bit, just undo the first four or so screws in the slit between the upper/lower halves of the dash and the screw at the bottom corner of the dash, then pull it down gently. Should be able to reach up underneath and feel it, or even see it from above.

97 and up it's above the gas pedal on the side of the tranny tunnel.

96 down are all the same TCU (at least as far as 91-96 are concerned, not sure about RENIX) 97 has its own unique TCU and 98-01 are all the same design as each other.

My bet is that you have either a blown fuse for the tranny, a wiring fault somewhere, or burnt solenoids.

The fact that 3 and OD act the same is a little worrying - are you sure? Maybe 3 is just a bit better?

The lack of 4lo is probably a misadjustment or bend in the transfer case shift linkage.

ok well im an idiot. after reading that the tcu is right there on that trim piece of the bottom half of the dash i realized i had that piece out to replace my steering column, so tomorrow i will go back up and plug it back in and im sure it will be good..

alek21 said:

ok well im an idiot. after reading that the tcu is right there on that trim piece of the bottom half of the dash i realized i had that piece out to replace my steering column, so tomorrow i will go back up and plug it back in and im sure it will be good..

Click to expand...

Doh! Yea that would do it. Actually, unplugging the TCU and seeing that you get the symptoms described (manually shifts okay) is the first test to check to determine if a shifting problem is electrical (usually) or mechanical.

hahaha wow... wish I could say I haven't ever done something like that before :dunce:

Jeeps run a lot better with the CPS, MAP, MAT, IAC, and upstream O2 sensors plugged into the harness.

Don't ask.