Aisen-Warner trans problem

1988 Jeep Cherokee 2wd 4.0 inline 6 cyl. Tranmission = Aisen-Warner Model 30-40LE 299560 miles

Problem just started. I have only owned this for a few months but it did shift normally before. When in Overdrive, Drive, 1-2, transmission starts out in low range but wont shift until speed reaches 35 mph then it shifts hard to second gear, but doesn't shift to third or overdrive. The transmission does not seem to be slipping while accelerating but when I let off the gas it does not slow down as I would expect, but is almost as if it is coasting. When you give it enough gas that the engine speed reaches the speed of travel it starts to accelerate again.

I have dropped the transmission pan, replaced pickup screen that wasn't all that dirty. Fluid is clean, not burned yet. Removed the three solenoid valves replaced the O-rings on the end of the valves. Checked valves to insure they opened & closed with battery volts applied. Installed fresh ATF. All valves work as I would expect. Removed what I think is a speed sensor in the tailshaft, located above the speedometer cable, that makes & breaks continuity when a magnet is past near the sensor.

I have a Haynes manual for the unit but the wiring diagrams don't include transmission control circuit.

Anyone with any ideas, info on how the electronics controls work for transmission shifts. Could someone tell me if another trans. could be installed, perhaps a Torqueflight that might bolt up to the 4.0 engine.

Reply to
Rick
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the tranny you have is a good and reliable and long-life design. a transmission specialist at a local jeep dealer said that he has never had to rebuild one. ( Even tho that was about 4 years ago.) A friend ('91 jeep) had the same sort of problem you describe, and was talked into a new transmission. After that, she still had EXACTLY the same problem.

Reply to
attnews

Reply to
L.W.(ßill) Hughes III

Does it shift like it thinks the pedel is on the floor? If so check the readings of you TPS (Throttle Position Sensor). This problem comes up about once a week here. the procedure is in the Haynes. Also note the standard and automatic ones are different. If that's not the problem there's a lot of info here.

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Reply to
Jo Bo

Drop the pan and check the band clearance 90% of the owners never have them checked.

HarryS

Reply to
HarryS

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God Bless America, ßill O|||||||O> mailto: snipped-for-privacy@aol.com
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Thanks for the link. I will see if I can find trans. control and break out the DVOM to check specs at connector.

Reply to
Rick

I do believe the trans to be ok, just have to figure why I'm not getting proper input to shift. Thanks.

Reply to
Rick

If you need a new tranny I have one for sale with 90 000 KM (about 50 000 miles), AISIN made in Japan.

Reply to
Miguel Londono

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