2013 JK Auto Trans Won't Shift Above 3rd
02-20-2021, 12:45 PM
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2013 JK Auto Trans Won't Shift Above 3rd
I can't find any threads about this so I'm hoping one of you can help...
2013 JKUR with the W5A580 Auto Trans.
TL;DR Backstory: Went wheelin'. Ran through a deeper water hole than I should have and got stuck. Water over the door sills and over my 35s on the passenger side (but not so high as to submerge the tranny breather...at least not if it is where I think it is on the pass. side of top of the engine). FWIW, the axles both have Trail Gear Creeper Breathers on them and their oil is fine. Got pulled out and finished the trail fine. Back on the road I can't shift above 2nd. After a mile or so, get a MIL. Check it and get "incorrect gear engaged" (I can't remember the code number). Check the fluid. It's dark. Needs to be changed but doesn't really look like it ingested water. Weigh my options and decide to drive the 70 miles home on backroads at 35 mph. Not the smartest, but it solved the immediate problem. Limp mode shouldn't actually hurt it, right?
Now, I'm reasonably mechanically savvy. In 21 years of driving, I've never had to take a vehicle to a shop. I've succeeded in fixing everything, including a full top-end rebuild from a snapped timing belt on a Volvo I picked up for $500 after the damage was done...
So, I drop the pan, inspect the fluid more closely. Not "milkshake-y". 128K on the OD. I did a fluid and filter "change" at about 120K. But, again, fluid is quite dark and probably needs a full flush so I do it. Replace the pan, pop the line off of the tranny cooler, hose clamp a hose from the "in" line at the cooler down to a drain pan. Run engine just until you see a bubble or two. Kill it. Refill with fluid and repeat. Just to be extra thorough in case it did ingest something, I run about 12 quarts of fresh fluid through it like that. Then refill to full and test drive. Somewhat predictably, it slips and is worse. The torque converter slips when at a stand still. I have to rev it a little to get moving. Not too big of a deal, I think. Higher mileage trannys often need a friction modifier. Also, it still won't shift above 2nd. I add a bottle of Lucas Stop Slip. It fixes the hesitation and now it shifts to 3rd...but not above. The 1-2 shift is perfect but the 2-3 shift is a bit rough.
I have a cheap but decent scanner. Both rear wheel speed sensors are showing what looks to be appropriate data. Both trans input speed sensors also look to be good and the same goes for the output speed sensor. The TCM is at least attempting to tell the 3-4 solenoid to fire (not sure how to tell if it actually is...scanner just goes from "not set" to "set" when it attempts to shift to 4th).
I'm out of ideas. I have an appointment at a dealer in a couple of days, but my pride really wants to solve it. In all of the Jeep-oriented forums out there, I read one case where I guy had similar symptoms and the diagnosis was "a bad circuit board" in the trans. I'm guessing that is the speed sensor module because I don't know of any other circuit boards inside of it. I can't think of how to test that other than process of elimination which I feel like I've done. The sensors all seem to output good data.
Any ideas, anyone?!?!
The thread with the "circuit board" comment: https://www.jk-forum.com/forums/modi...4/#post3869146
2013 JKUR with the W5A580 Auto Trans.
TL;DR Backstory: Went wheelin'. Ran through a deeper water hole than I should have and got stuck. Water over the door sills and over my 35s on the passenger side (but not so high as to submerge the tranny breather...at least not if it is where I think it is on the pass. side of top of the engine). FWIW, the axles both have Trail Gear Creeper Breathers on them and their oil is fine. Got pulled out and finished the trail fine. Back on the road I can't shift above 2nd. After a mile or so, get a MIL. Check it and get "incorrect gear engaged" (I can't remember the code number). Check the fluid. It's dark. Needs to be changed but doesn't really look like it ingested water. Weigh my options and decide to drive the 70 miles home on backroads at 35 mph. Not the smartest, but it solved the immediate problem. Limp mode shouldn't actually hurt it, right?
Now, I'm reasonably mechanically savvy. In 21 years of driving, I've never had to take a vehicle to a shop. I've succeeded in fixing everything, including a full top-end rebuild from a snapped timing belt on a Volvo I picked up for $500 after the damage was done...
So, I drop the pan, inspect the fluid more closely. Not "milkshake-y". 128K on the OD. I did a fluid and filter "change" at about 120K. But, again, fluid is quite dark and probably needs a full flush so I do it. Replace the pan, pop the line off of the tranny cooler, hose clamp a hose from the "in" line at the cooler down to a drain pan. Run engine just until you see a bubble or two. Kill it. Refill with fluid and repeat. Just to be extra thorough in case it did ingest something, I run about 12 quarts of fresh fluid through it like that. Then refill to full and test drive. Somewhat predictably, it slips and is worse. The torque converter slips when at a stand still. I have to rev it a little to get moving. Not too big of a deal, I think. Higher mileage trannys often need a friction modifier. Also, it still won't shift above 2nd. I add a bottle of Lucas Stop Slip. It fixes the hesitation and now it shifts to 3rd...but not above. The 1-2 shift is perfect but the 2-3 shift is a bit rough.
I have a cheap but decent scanner. Both rear wheel speed sensors are showing what looks to be appropriate data. Both trans input speed sensors also look to be good and the same goes for the output speed sensor. The TCM is at least attempting to tell the 3-4 solenoid to fire (not sure how to tell if it actually is...scanner just goes from "not set" to "set" when it attempts to shift to 4th).
I'm out of ideas. I have an appointment at a dealer in a couple of days, but my pride really wants to solve it. In all of the Jeep-oriented forums out there, I read one case where I guy had similar symptoms and the diagnosis was "a bad circuit board" in the trans. I'm guessing that is the speed sensor module because I don't know of any other circuit boards inside of it. I can't think of how to test that other than process of elimination which I feel like I've done. The sensors all seem to output good data.
Any ideas, anyone?!?!
The thread with the "circuit board" comment: https://www.jk-forum.com/forums/modi...4/#post3869146
Last edited by colthoss; 02-20-2021 at 12:48 PM.
02-21-2021, 11:58 AM
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While I suppose anything is possible, it doesn't seem like either of those.
A bad toque converter wouldn't allow it to drive quite normally through 3rd gear. I live in the middle of town so 95% of my driving is under 45 mph. So I've been driving it like that for about a week. Drives almost perfectly except a slightly hard shift from 2nd to 3rd.
And worn clutch packs would allow the engine to rev when it engages the worn out gear. When it attempts to shift to 4th, the rpms actually drop a little. It's as if the computer isn't allowing it so it kills the throttle too.
A bad toque converter wouldn't allow it to drive quite normally through 3rd gear. I live in the middle of town so 95% of my driving is under 45 mph. So I've been driving it like that for about a week. Drives almost perfectly except a slightly hard shift from 2nd to 3rd.
And worn clutch packs would allow the engine to rev when it engages the worn out gear. When it attempts to shift to 4th, the rpms actually drop a little. It's as if the computer isn't allowing it so it kills the throttle too.