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AW4 misbehaving

hannibal

NAXJA Forum User
Location
Wisconsin
I have a 1996 Cherokee with the 4.0 liter and AW4. I'm just about to turn 150,000 miles and the shifting has become erratic.

If I really baby the throttle from a stop, most of the time it will upshift but it seems to be going all the way up to 3rd or overdrive. It shifts but gets real doggy like it is trying to pull in too high of a gear.

If I apply a regular amount of throttle from a stop, it doesn't want to shift. I have to goose the throttle and rev it up to about 3000 rpm and back off the gas to get it to shift. Even then, it still feels like it shifted up too high.

I've already replaced the trottle position sensor because it was cheap and easy to access. I believe there is a fuse in the fuse block as well as an inline fuse to the transmission control module that should be checked.

Where is the TCM located on the 1996 Cherokee? I believe later years have it under the PS glovebox.

Any suggestions as to what type of gremlin I have here? I'm hoping it is a simple electrical problem rather than a mechanical one. I don't have a multimeter so I can't check the various voltages myself though.

Thanks
 
I printed out the information from the link above and bought a multimeter last night. It is a cheap Craftsman CAT II-600V autoranging model. I'm going to apologize in advance because I am not an electrical person.

The article references a 7.5 amp #13 fuse. There is a spade connector in that location on my Cherokee and but there is a 7.5 amp fuse in #17 which was OK.

I removed the lower panel and located the TCU but I don't see the 15 amp inline fuse or resistor pack the article references. I traced the wiring all the way up to the firewall.

Here are the readings that I took. All were taken with a good ground (I ran a wire to the negative on the battery) except for the Converter Clutch Solenoid resistance which specified to use D7. All readings were taken with the TCU unplugged.

C3 - I don't understand the reference to "pulse per one revolution." The reading was 1.6mV.

C8 - Started at 15V and dropped the longer I kept the contacts in place.

C9 - Started at 15V and dropped the longer I kept the contacts in place.

C10 - 21.6 mV Brake off. Didn't check brake on.

C11 - I don't know what a "comfort switch" is.

D7/C14 - 0 Ohms

C15 - 299.5 Ohms

C16 - 24.3 Ohms

D1 - Pin was not used on my Cherokee

D2 - 0.8V closed throttle. Did not check wide open.

D3 - 8.7mV

D14 - 12.22V

D16 - 12V

The solenoid readings don't seem right. C14 is at 0, C15 is much higher than the recommended 11-15 at 299.5, and C16 is slightly higher than the recommended 11-15 at 24.3.

Any suggestions?
 
The article is geared towards the older Jeeps so some things are different. There is no inline fuse on a 96. If its shifting at all the fuses are fine. You don't have a power/comfort switch either.

I don't have a 96 FSM to confirm, but I don't think the wiring connector changed until 1997. My 97 FSM shows two rows if 13 pins, versus 2 rows of 16 pins. If it did change, then its pins 11-13 for the solenoids.

On the C3 measurement, that should be done with the connector plugged in and ignition on. If you rotated the drive shaft you'd see the voltage pulsing once per revolution. If its shifting, this speed sensor is likely just fine.

C8/C9/C10 look fine. Ignore C11 as you don't have the power/comfort switch. D1/D2/D3 look fine. D1 isn't used on 92+ Jeeps. D14/D16 supply voltages look fine.

I agree the C14, C15, and C16 resistance measurements look suspect. Assuming those measurements are good, I think you're looking at replacing the solenoids. Before buying solenoids, I would removing the oil pan from the tranny and measure the solenoids directly (with the TCU still unplugged). That will eliminate any problems with the wiring to the tranny.

Someone recently had a link for buying replacement solenoids cheaper than the dealer. Googling "Rostra # 52-9002" gave me http://www.transmissionpartsusa.com/Solenoid_kit_A340E_1985_on_p/940-00094393a.htm (its a Toyota made tranny, btw). A little pricey, but an good option if you can't find any at the junkyard or eBay.
 
I purchased the 3-solenoid kit from the link provided above by lawsoncl. They cost me $160.84 from transmissionpartsusa.com delivered to my door and were identical to the factory solenoids. The kit was part #940-00094393A.
 
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