Transmission Shifting Out of 1st Issue
12-25-2014, 09:01 PM
#1
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Year: 1997
Model: Cherokee
Engine: 4.0 I6
Transmission Shifting Out of 1st Issue
'97 XJ 4.0 4x4
240k miles
7.5" lift on 35's
Stock gearing - not good I know
Trying to diagnose transmission issue on what I'm pretty sure is the Aisin AW4 tranny. I do have a B&M trans cooler and temp gauge installed.
When the tranmission is cold(120 deg or less) it will not shift from 1st to 2nd until I reach about 25mph. That is, if I'm starting from a stop my engine RPM's will climb and climb, redlining if I allowed it to. It's not until I reach 25mph that I can let out of the throttle and allow it to shift and begin to add throttle back in. If im below 25mph I can get the RPM's up to 3500 and it will not shift for me, even letting out of the throttle it won't shift. Once the trans reaches warmer operating temps it will shift out of 1st at much lower RPM's, a little over 2k if I recall.
Sorry if this doesn't make sense, its hard to explain. I may have to put a video on YouTube for you guys, or worse go to a mechanic! I know little about trannys and how they work but could there be a mechanism sticking and when it warms up this mechanism works freely?
It's been going on for awhile now, I don't think its related to outdoor temps since it started this back during warmer weather. Now since its colder it just takes longer for the tranny to heat up and the issue to go away. I have changed the fluid and filter with no change whatsoever.
240k miles
7.5" lift on 35's
Stock gearing - not good I know
Trying to diagnose transmission issue on what I'm pretty sure is the Aisin AW4 tranny. I do have a B&M trans cooler and temp gauge installed.
When the tranmission is cold(120 deg or less) it will not shift from 1st to 2nd until I reach about 25mph. That is, if I'm starting from a stop my engine RPM's will climb and climb, redlining if I allowed it to. It's not until I reach 25mph that I can let out of the throttle and allow it to shift and begin to add throttle back in. If im below 25mph I can get the RPM's up to 3500 and it will not shift for me, even letting out of the throttle it won't shift. Once the trans reaches warmer operating temps it will shift out of 1st at much lower RPM's, a little over 2k if I recall.
Sorry if this doesn't make sense, its hard to explain. I may have to put a video on YouTube for you guys, or worse go to a mechanic! I know little about trannys and how they work but could there be a mechanism sticking and when it warms up this mechanism works freely?
It's been going on for awhile now, I don't think its related to outdoor temps since it started this back during warmer weather. Now since its colder it just takes longer for the tranny to heat up and the issue to go away. I have changed the fluid and filter with no change whatsoever.
12-26-2014, 04:57 AM
#3
Could be a shift solenoid sticking.....................I have replaced them in other trannys before. I have never replaced one in the AW4, but I hear it's not very difficult........(hardest part would probably be getting the pan off)
As freegdr suggested.................Check the "TV" cable first to make sure it operates properly...............
As freegdr suggested.................Check the "TV" cable first to make sure it operates properly...............
12-26-2014, 07:59 AM
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12-26-2014, 08:52 AM
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It could be a sticking 1-2 solenoid, a defective 1-2 solenoid, or a lack of control signal to the 1-2 solenoid from the TCM. Other than this, the valve body may be defective.
When's the last time you changed your trans fluid? What trans fluid are you using...Dexron III/Mecon?
No CEL? Does the CEL bulb work?
Back to solenoid 1-2:
1–2 SHIFT VALVE
The 1–2 shift valve controls the 1–2 upshifts and downshifts. The valve is operated by the “A” valve body solenoid and line pressure from the manual valve, second coast modulator valve and the 2–3 shift valve.
When the transmission control module deactivates the solenoid, line pressure at the top of the valve moves the valve down closing the second brake accumulator feed port. As the solenoid is activated and the drain port opens, spring force moves the valve up exposing the second brake feed port for the shift to second gear.
If you have a digital Volt/Ohmmeter you chan check the resstance of the 1-2 (A) solenoid from the TCM connector. It involes accessing the TCM and removing the TCM connector.
Here's the TCM connector pin-out and functions chart. You are interested in Pn Cavity 12, but you should check the other two solenoids while you're at it.
Here's the TCM systems tests. The Preliminary Resistance Checks Steps need to be accomplished and the Specific Resistance Checks, steps 5., 6., and 7. should be accomplished.
When's the last time you changed your trans fluid? What trans fluid are you using...Dexron III/Mecon?
No CEL? Does the CEL bulb work?
Back to solenoid 1-2:
1–2 SHIFT VALVE
The 1–2 shift valve controls the 1–2 upshifts and downshifts. The valve is operated by the “A” valve body solenoid and line pressure from the manual valve, second coast modulator valve and the 2–3 shift valve.
When the transmission control module deactivates the solenoid, line pressure at the top of the valve moves the valve down closing the second brake accumulator feed port. As the solenoid is activated and the drain port opens, spring force moves the valve up exposing the second brake feed port for the shift to second gear.
If you have a digital Volt/Ohmmeter you chan check the resstance of the 1-2 (A) solenoid from the TCM connector. It involes accessing the TCM and removing the TCM connector.
Here's the TCM connector pin-out and functions chart. You are interested in Pn Cavity 12, but you should check the other two solenoids while you're at it.
Here's the TCM systems tests. The Preliminary Resistance Checks Steps need to be accomplished and the Specific Resistance Checks, steps 5., 6., and 7. should be accomplished.
12-26-2014, 02:00 PM
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It could be a sticking 1-2 solenoid, a defective 1-2 solenoid, or a lack of control signal to the 1-2 solenoid from the TCM. Other than this, the valve body may be defective.
When's the last time you changed your trans fluid? What trans fluid are you using...Dexron III/Mecon?
No CEL? Does the CEL bulb work?
Back to solenoid 1-2:
1–2 SHIFT VALVE
The 1–2 shift valve controls the 1–2 upshifts and downshifts. The valve is operated by the “A” valve body solenoid and line pressure from the manual valve, second coast modulator valve and the 2–3 shift valve.
When the transmission control module deactivates the solenoid, line pressure at the top of the valve moves the valve down closing the second brake accumulator feed port. As the solenoid is activated and the drain port opens, spring force moves the valve up exposing the second brake feed port for the shift to second gear.
If you have a digital Volt/Ohmmeter you chan check the resstance of the 1-2 (A) solenoid from the TCM connector. It involes accessing the TCM and removing the TCM connector.
Here's the TCM connector pin-out and functions chart. You are interested in Pn Cavity 12, but you should check the other two solenoids while you're at it.
Here's the TCM systems tests. The Preliminary Resistance Checks Steps need to be accomplished and the Specific Resistance Checks, steps 5., 6., and 7. should be accomplished.
When's the last time you changed your trans fluid? What trans fluid are you using...Dexron III/Mecon?
No CEL? Does the CEL bulb work?
Back to solenoid 1-2:
1–2 SHIFT VALVE
The 1–2 shift valve controls the 1–2 upshifts and downshifts. The valve is operated by the “A” valve body solenoid and line pressure from the manual valve, second coast modulator valve and the 2–3 shift valve.
When the transmission control module deactivates the solenoid, line pressure at the top of the valve moves the valve down closing the second brake accumulator feed port. As the solenoid is activated and the drain port opens, spring force moves the valve up exposing the second brake feed port for the shift to second gear.
If you have a digital Volt/Ohmmeter you chan check the resstance of the 1-2 (A) solenoid from the TCM connector. It involes accessing the TCM and removing the TCM connector.
Here's the TCM connector pin-out and functions chart. You are interested in Pn Cavity 12, but you should check the other two solenoids while you're at it.
Here's the TCM systems tests. The Preliminary Resistance Checks Steps need to be accomplished and the Specific Resistance Checks, steps 5., 6., and 7. should be accomplished.
Bought my jeep back in 2007 and one of the first things I did was change all fluids. At the parts store I was told by the employee helping me that I need to be using ATF+4. He explained that Chrysler released a service document of some sort stating that ATF+4 was be be used in my tranny. He even showed me the document on the computer because I insisted he was wrong. It wasn't until February of this year I read on this forum the controversy of using ATF+4.
I wasn't having any trans problems at the time but I decided to push my luck and switch back to Dex/Merc. I did 4-5 drain and refills about a thousand miles apart, first one was about 500 miles. Everything's been fine up until around Sept/October.
So to answer your question my last fluid change was a little over 3000 miles ago and I'm now currently using Dex/Merc and its nice and red. I will get out either this afternoon or tomorrow to perform the TCM checks you gave me. Thanks!
12-27-2014, 11:00 AM
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It could be a sticking 1-2 solenoid, a defective 1-2 solenoid, or a lack of control signal to the 1-2 solenoid from the TCM. Other than this, the valve body may be defective.
When's the last time you changed your trans fluid? What trans fluid are you using...Dexron III/Mecon?
No CEL? Does the CEL bulb work?
Back to solenoid 1-2:
1–2 SHIFT VALVE
The 1–2 shift valve controls the 1–2 upshifts and downshifts. The valve is operated by the “A” valve body solenoid and line pressure from the manual valve, second coast modulator valve and the 2–3 shift valve.
When the transmission control module deactivates the solenoid, line pressure at the top of the valve moves the valve down closing the second brake accumulator feed port. As the solenoid is activated and the drain port opens, spring force moves the valve up exposing the second brake feed port for the shift to second gear.
If you have a digital Volt/Ohmmeter you chan check the resstance of the 1-2 (A) solenoid from the TCM connector. It involes accessing the TCM and removing the TCM connector.
Here's the TCM connector pin-out and functions chart. You are interested in Pn Cavity 12, but you should check the other two solenoids while you're at it.
Here's the TCM systems tests. The Preliminary Resistance Checks Steps need to be accomplished and the Specific Resistance Checks, steps 5., 6., and 7. should be accomplished.
When's the last time you changed your trans fluid? What trans fluid are you using...Dexron III/Mecon?
No CEL? Does the CEL bulb work?
Back to solenoid 1-2:
1–2 SHIFT VALVE
The 1–2 shift valve controls the 1–2 upshifts and downshifts. The valve is operated by the “A” valve body solenoid and line pressure from the manual valve, second coast modulator valve and the 2–3 shift valve.
When the transmission control module deactivates the solenoid, line pressure at the top of the valve moves the valve down closing the second brake accumulator feed port. As the solenoid is activated and the drain port opens, spring force moves the valve up exposing the second brake feed port for the shift to second gear.
If you have a digital Volt/Ohmmeter you chan check the resstance of the 1-2 (A) solenoid from the TCM connector. It involes accessing the TCM and removing the TCM connector.
Here's the TCM connector pin-out and functions chart. You are interested in Pn Cavity 12, but you should check the other two solenoids while you're at it.
Here's the TCM systems tests. The Preliminary Resistance Checks Steps need to be accomplished and the Specific Resistance Checks, steps 5., 6., and 7. should be accomplished.
12.2 ohms across pin CAV 24 and CAV 11,12,13. I went through all the other tests for the heck of it and all checked out except I had no reading on pin CAV 4(output speed sensor) and no voltage reading when trans is put into reverse, all other gears and throttle positions show proper volatage specs.
Last edited by Jeepin'Hubb's; 12-27-2014 at 11:09 AM.
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12-27-2014, 11:34 AM
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Okay I just got done performing the tests that you had given me for the TCM. I believe all the resistance checks were within spec;
12.2 ohms across pin CAV 24 and CAV 11,12,13. I went through all the other tests for the heck of it and all checked out except I had no reading on pin CAV 4(output speed sensor) and no voltage reading when trans is put into reverse, all other gears and throttle positions show proper volatage specs.
12.2 ohms across pin CAV 24 and CAV 11,12,13. I went through all the other tests for the heck of it and all checked out except I had no reading on pin CAV 4(output speed sensor) and no voltage reading when trans is put into reverse, all other gears and throttle positions show proper volatage specs.
As stated earlier it could be a mechanically sticking 1-2 solenoid. If you don't get a CEL (Sol A fault) this could be the case. Otherwise, it could be a valve body defect.
12-27-2014, 11:43 AM
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Yes the backup lights work. And no I'm not getting any CEL. The bulb does work. What would you recommend I try next, replace Solenoid A?
12-27-2014, 12:12 PM
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12-27-2014, 01:08 PM
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If you search around, like on Rockauto, you can find solenoids by OEM part number cross referenced to aftermarket solenoids.
1997 Solenoid C OEM 4797403 (new part number 5016121AA)
1997 Solenoids A and B OEM 4797402 (new part number 50161120AA)
12-27-2014, 03:56 PM
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In my opinion, quality=OEM...but they are mega bux.
If you search around, like on Rockauto, you can find solenoids by OEM part number cross referenced to aftermarket solenoids.
1997 Solenoid C OEM 4797403 (new part number 5016121AA)
1997 Solenoids A and B OEM 4797402 (new part number 50161120AA)
FYI, the first time I drove the jeep after doing the tcm checks my Check Engine light was on, then was off after driving a bit(to store) then shutting down and restarting. Im thinking it was probably because of having the TCM unplugged with power to the PCM, but that's only a guess.
12-27-2014, 05:35 PM
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If mega bucks is more than what I'm seeing on Rockauto than it looks like im going to have to make a compromise on this job...ouch.
Like the red necks say: If you want to dance you got to pay the fiddler.
FYI, the first time I drove the jeep after doing the tcm checks my Check Engine light was on, then was off after driving a bit(to store) then shutting down and restarting. Im thinking it was probably because of having the TCM unplugged with power to the PCM, but that's only a guess.
Like the red necks say: If you want to dance you got to pay the fiddler.
FYI, the first time I drove the jeep after doing the tcm checks my Check Engine light was on, then was off after driving a bit(to store) then shutting down and restarting. Im thinking it was probably because of having the TCM unplugged with power to the PCM, but that's only a guess.
Step 1.1. of the Preliminary Resistance Checks Steps.