New trans???
 

Well got my new trans in bought it off a buddy I actually knew the trans was good but I put it in my jeep and it slips as bad as mine did

I had someone tell me this could be the tps

it can slip if fluid level is low.
Brand new or rebuilt?

Did you clean the connections? Did you clean the tranny cooler lines before the installation?
The connections could be dirty or if you didn't clean the lines you could have got some of the trash in your lines inside your new tranny.

Disconnect the upper transmission line
from the radiator. Push a 4-5 foot length of
hose onto the fitting on the radiator and
drop the other end in a 5 gallon bucket.
Tips: A length of old 5/8" garden hose
works for this. Use a worm clamp to hold
the hose on the fitting. Trust me, you don't
want this coming loose. Place a 3" C- clamp
or some other contraption on the rim of
the bucket to hold the end of the hose a
couple inches inside the top of the bucket.
Again, you don't want this coming loose.
Stick a decent sized funnel in the fill tube
for the tranny and arm yourself with 8-10
quarts of the proper ATF. Now you need a
helper.
Have the helper start the engine and keep
their foot on the brake. As soon as they do,
your old black fluid will start coming out of
the hose into the bucket. Your job is to
pour new fluid down the fill hole at the
same rate its coming out of the hose. Don't
worry about being exact, just keep the
funnel full. Keep watch of the fluid going
into the bucket. It should start looking
better. After your first gallon, have your
friend, with e-brake and foot brake both
applied, shift through the full range of
gears, stopping for about a 4 count at each
spot. Once he's at the bottom, he can put
it in Park for the rest of the process. When
you see nice red fluid coming out of the
hose, stop filling the funnel and let it
empty. About 5 seconds after it does, have
your friend kill the engine.
Hook everything back up. You've just done
a complete, or nearly complete change of
your fluid, including all that sits in the
torque converter! This method is a "
forward flush" as apposed to a "reverse
flush" that many shops do. The forward
flush I'd far less likely to damage all the
seals in the tranny and is gentler on things
as it uses the tranny's own pump and
normal operating pressures to do the flush!
Once you're done and everything is
buttoned up, take it for about a 15 mile
drive to get everything up to full hot. Check
and top off your fluid as necessary.
Got to give Macgyver35 props for the write up.
Good luck.

As far as connection and fluid everything is perfect the old trans slipped in all gears except 1-2 and reverse new (used) does the same I was told by another guy who knows jeeps well that the tps could be the problem after he said this my check engine light is on so could this be the problem

I don't see how a tps could cause the tranny to slip. TCM could cause it, low line pressure, bad solenoid, low on fluid can all cause a slip but tps doesn't make sense to me.

Wow I stand corrected. I thought it was controlled by the tcm and line pressure, not the tps. Thanks for the link!.

Hey I found it just as weird and didn't believe it either!! I guess I'll give it a try before settin fire to the damn thing

Do you know the codes it's throwing?

No I'm not sure haven't tried yet

No I'm not sure haven't tried yet

When my tranny went out I couldn't get my XJ to Advance Auto nor could I get her to the shop either. So I went to Advance Auto and bought a reader.
It was around $121 but they had cheaper one's there though.

If you have an android smartphone there is a program called Torque that can sync with a bluetooth OBDII dongle you can purchase on amazon for about thirty bucks. A lot cheaper.

Wow I didn't know that. I love this forum. It's. a tool in my bag of tricks.