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AW4 stuck in 1st gear when cold

X

XJSteven

NAXJA Forum User
Location
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Every morning when my XJ is cold (or on an afternoon after it's been sitting all day) it won't shift out of 1st gear until I've driven it for half a mile or so and it has warmed up. It revs upward of 4,000 rpm but eventually I can trick it into changing into 2nd gear by backing off the pedal a few times and accelerating. It works fine after that with no shifting problems until the next time it is cold.

There are no codes and I've changed the TPS. I changed #1 and #2 solenoids over today and both the old and replacement solenoids showed a reading of approx 12 ohms. It has made no difference and I'm still stuck in 1st gear when cold.

Any suggestions on what to try next?
 
How many miles? My taurus does the same thing.
Get it power flushed at a trans shop. I have had good luck with LUCAS trans products.
 
It's done 220 miles. I haven't flushed it but I just changed the filter and trans oil. I've also adjusted the kickdown cable.
 
XJSteven said:
It's a 96 XJ. I have a spare TCM but I haven't swapped it over yet. Should that be my next step?
Click to expand...

Yea! Try the TCM.

Also, check that the oil level is not too high. A few years ago while working in Iowa, my XJ did that, it was slow to shift for about the first mile +/- even at highway speeds. The oil level was above the full mark when cold. What tire size and gear ratio combination are you using?
 
I've been running 4.10 ratios with 31" tyres for a few years now with no issues. I rechecked the oil level and it''s not too high. Adjusted the kickdown cable and that made no difference either so I pulled the TCM fuse and it manually shifted through the gears fine, this was still while cold.

I guess it's time to try the TCM. Any other suggestions before I do that?
 
Cruiser’s Trans Plug Refreshing

Over near the transmission dipstick tube are 2 rather large connectors. One is black and the other gray. These 2 connectors carry all the info between TPS, TCU, NSS, speed sensor, and transmission solenoids.
Unplug each one, visually inspect for corrosion or bent pins, spray them out with electrical contact cleaner and plug them back in.
　
Additionally, if your Jeep is an 87 to 90 Renix, it’s always a good idea to reach up under the glovebox area and unplug the connector to the TCU and spray it out along with the receptacle of the TCU. While you’re there, find the fuse right in that area for the TCU. Remove it and spray out it’s receptacle and clean any corrosion from the fuse.
Revised 9-10-2012

 
I swapped the TCM over but still have the same problem. The oil level was right on the Full mark when hot but I checked it this morning when cold (engine not running) and it was higher up the dipstick above the full mark so now I'm confused. I've removed about half a litre of transmission oil and I might put some of this stuff in:

http://www.nulon.com.au/products/Specialty_Products/Auto_Transmission_Treatment/#.UcfvcNg7tx0

I'll unplug and inspect the black and gray connectors too.
 
It is a gummed up or sticky something inside the trans. My taurus does this same thing when cold first shift of the day, after that it is fine.
 
XJSteven said:
I swapped the TCM over but still have the same problem. The oil level was right on the Full mark when hot but I checked it this morning when cold (engine not running) and it was higher up the dipstick above the full mark so now I'm confused. I've removed about half a litre of transmission oil and I might put some of this stuff in:

http://www.nulon.com.au/products/Specialty_Products/Auto_Transmission_Treatment/#.UcfvcNg7tx0

I'll unplug and inspect the black and gray connectors too.
Click to expand...

The level is ONLY to be checked/adjusted per the dipstick instructions.
 
Well after all that it turns out it was the TPS which was the first thing I changed. The new one I put in was faulty too. :( I swapped it over and the transmission now shifts smoothly into second when cold.

I still have an issue with a lack of power/acceleration in other gears when cold, but that is a separate problem. If I put my foot down there's no acceleration, the revs stay constant and it feels like the motor is being starved of fuel. It runs fine once it's warmed up. I've got dual fuel installed so I can rule out the fuel pump etc. Any suggestions on what other sensors I should test first?
 
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