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Shifting problems - solenoids?

padre10

NAXJA Forum User
Location
MO
I tried asking this on another forum, but I'm not getting much response. I've read about everything transmission-related on here that I could find, but apologies if I missed an obvious answer to my question somewhere.

My 98 XJ (4.0) AW4 suddenly started not shifting out of first the other night. If I let up on the gas it would go up to higher gears, but if I didn't it seemed like it would probably redline without shifting. It threw a CEL, and the scan tool said P0700 (Transmission Control System), P0753 (Shift Solenoid A Electrical) and P0751 (Shift Solenoid A Performance or Stuck Off). Fluid looked fine.

After reading on here and elsewhere, I replaced the TPS first. No luck. It's shifting out of first now (a little late, but it does it), but *seems* to be skipping 2nd and going straight to 3rd. (If I put the lever in 1/2 it seems to stay in 1). Besides the TPS replacement and an attempt at adjusting my throttle valve cable (it seemed to be fine), I haven't done anything else.

I did check the resistance of the solenoid circuits at the TCU, and they were within range. At least I *think* they were — it was hard to get a consistent reading.

Prior to this, I had 2-3 instances where it seemed to delay going into first gear in the last several months, but just a moment's hesitation and no further problems.

At any rate, I'm stumped. Before I shell out the $200 and an afternoon's work to try the solenoids, any other suggestions? And can I count on their resistance being off at the TCU if they're bad, or might they be bad and read OK?

Thanks!
 
I have read where they can read good until they warm up, then fail and read bad while hot. Somebody posted just the other day where they had to rig up taps at the TCU to his meter to catch one solenoid going to 50 ohms when the transmission acted up. He had been through hell using a transmission shop, and got tired of the run around. It was the second bad solenoid off the shelf or they lied about replacing it....

Anyway, best way to test is at the solenoid, pulling the valve cover and filter (draining about 2.5 quarts of fluid), to get to them. Sounds like you just need one solenoid, unless the wires are loose between the TCU and solenoid, or a ground is loose. I have seen them on Ebay for a lot less. Might check Rock auto too!
 
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