shifting problems

I have a 90 XJ and i am having problems with the automatic transmission. when i go to get on the freeway it will not down shift at all. it will up shift fine but i have no down shifting. can anyone help me with this.

could be a bad or out of spec tps.

can you manually downshift?

have you checked the level and condition of the fluid?

is the tv cable adjusted proporly?

you need to figure out if its an electrical problem(tps, tcu, shift solinoids in the trans) or mechanical problem.

i can down shift it by hand but that's it. how would you recommend i track the problem down. this is my first jeep and i don't know much about it.

poomero said:

i can down shift it by hand but that's it. how would you recommend i track the problem down. this is my first jeep and i don't know much about it.

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If you don't have a digital multimeter, buy one. If you have to buy one you should spend about $20 for it, that should get you a MM with good ranges and an audible circuit tester feature.

Buying the FSM for your year is best. Two book set. If you use search you will find most of the test procedures, some with pictures, can be found here.
Haynes and Chiltons manuals are not worth much, they try and cover too many years and are either too generic or even wrong in some places.

Your TPS needs to be tested. Plenty info here already, use search. Also, to do a throttle range test, that is, to test the TPS response throughout its range you need an analog MM. Digital MM have buffering circuits built into them and will mask the results. Analog meters are $4 or less.

Check and adjust the throttle cable, it is your kickdown. Again, search.

There is a fuse to the TCU, be sure to check that.

Keep us updated.

thanks for the help.