i have a 96 xj sport i warm up my xj evervy time i drive it. Now that its cold out my trans. shifts hard after i drive it for a little it smooths out. I checked the fluid and its full. does anybody have a clue on whats going on?

 

For future reference on "why does it do x" type posts, in addition to year of jeep, always include:

Engine (4 or 6 cylinder)
Mileage
2WD or WD
Any mods or recently replaced stock parts that may have something to do with your problem (EX: alignment issues, you should list any lift or other suspension mods/repairs)
Specific temps if possible. "Hot", "warm" and "cold" are relative, open to interpretation, and have different meanings for different components.

At any rate, letting your Jeep sit for 5 or 10 minutes in the driveway as a warm-up will warm up the engine. The transmission? Not so much. You really have to be driving the thing to get trans temps up in anything under about 30-40 minutes. Once the engine is hot you'll be circulating warmed fluid through the trans (the trans fluid will now be passing through a warm to hot radiator), but it's not the same as if the vehicle had been driven at 40+ MPH for the last 20 minutes.

My guess is your trans fluid is toast. Is it dark brown or black? It should be distinctly red in color. Dark red is passable, but it should definitely be more red than anything else. If it looks bad or smells burned, changing it will probably fix your issues. Either way, if it looks and smells bad, it should be replaced anyway, if for no other reason than to eliminate bad fluid as a cause of issues. I suppose you could have failing shift solenoids, but I'd start with fluid change if it looks like it could use it.

Here's my preferred method for changing it (copied from one of my earlier posts). It's faster, easier, more thorough, and less likely to have you dealing with new leaks than other methods.

Black/dark fluid is a bad sign. Personally, rather
then draining the pan 4 or 5 times,only changing
3 quarts at a time I
prefer the "let the tranny pump do the
work" method.
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 is 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. This method is also done all top side, so its easier to stay clean, doesn't require crawling under there on your back, or trying to change all the fluid 3 quarts at a time by draining the pan multiple times.

 

thanks its 96 xj sport 160,000 miles 4wd i6 aw4 trans 231np tc dana 30 3.55 front diff rear diff c8.25 trans fluid is red smells like *** but not burnt didnt have this problem in the summer but now that its cold its an issue i changed the fluid and filter last spring when i put it in. Its been driven but not hard its a daily driver .

 

Try this:

https://www.cherokeeforum.com/f2/free-quick-fix-41821/

 

Hi, sorry to dig up this old thread but am about to do this. Mine is a RHD (in Oz) and as far as I know, the UPPER transmission line connected to the radiator is the INLET. So, connecting a hose to the fitting on the radiator when you disconnect this line, as stated above marked in red, will do nothing but will let the ATF just pore out the transmission line, since you connect the hose to the inlet.. Connecting a hose to the disconnected transline would work (but will be a pain since the fitting is a bolt-on type). Is this correct??
Appreciate your clarification.

 

I have a trans cooler so wat I did was find the return line to the trans and hooked a hose up to that. Then ran the process above.