Auto Trans won’t Manually Shift. 2012
10-30-2017, 01:06 PM
#1
JK Enthusiast
Thread Starter
Auto Trans won’t Manually Shift. 2012
After replacing axles with other 3.73 geared axles, my jeep won’t shift manually. Seems like it’s stuck in high gear. Starts off very sluggish and won’t let me manually shift. Prior to replacing the axles I had blown out the gears in the rear, and then tried to limp it on the front, when at about 20-30mph the rear jammed everything up and locked up the front and blew it out. The jeep shifts into 4lo and 4hi and stuff. Someone tell me something good because I’m getting scared my transmission might be messed up.
Axles were supposed to be 3.73 like my stock gears. Idk what the deal is. Hopefully it’s just the computer being weird?
Axles were supposed to be 3.73 like my stock gears. Idk what the deal is. Hopefully it’s just the computer being weird?
10-30-2017, 03:58 PM
#2
JK Jedi
When you say "they were supposed to be 3.73", you didn't open them up and count the ring rotations as you turned the pinion to verify? Sounds almost the oppposite of being in limp mode though in that it is stuck in a high gear whereas limp mode sticks you in low gear.....at least that is my experience. Subscribed to see if others has suggestions.
10-30-2017, 07:04 PM
#3
JK Enthusiast
Thread Starter
When you say "they were supposed to be 3.73", you didn't open them up and count the ring rotations as you turned the pinion to verify? Sounds almost the oppposite of being in limp mode though in that it is stuck in a high gear whereas limp mode sticks you in low gear.....at least that is my experience. Subscribed to see if others has suggestions.
Anyway, went to lunch at work, go outside to check again, start it up, drive around parking lot, hold shifter toward downshift position, it goes into first, but then wouldn’t let me go out of first. So I circle back around, Park, and then sit there for a minute. Notice check engine light is on. Tried to go circle lot again, put it in reverse, and nothing. Like it’s in neutral or something, just revved. Went to drive, same thing, just revved. Then put it in park and went back inside.
It drove about 2-3 miles to my work, then I got it into first in the parking lot, so I’m thinking my transmission is (hopefully) fine. Hoping it’s a computer issue. My battery did die while my jeep was sitting for a couple months. I’ve read something about the tranny losing power and then going into tranny limp mode and reverting to 3rd gear. But idk if that was a jeep.
Hopefully can get this sorted out without going to the dealer. I’m sure they won’t warranty shit on my jeep since it has lift and 37s and full body armor and beadlocks. They’ll say my mods caused the problem.
It’s a 2012 sport unlimited.
10-30-2017, 07:47 PM
#4
you got check engine light? pull codes - I'm betting money you have a gear ratio issue and you are in limp mode. You mentioned your battery died also. So here's a possibility - you have the right axles but the computer does not remember that you have 37's and it is seeing wrong rotation speed on the wheel sensor in relation the RPM's and speed and is deciding that something is wrong. Other option, the settings in the computer held but the axles are wrong.
Oh yeah, when did you upgrade the tires to 37's? While it was sitting with a dead battery? If so did you reprogram your ECU for the new tire size?
So to go full cirlce - pull codes.
Oh yeah, when did you upgrade the tires to 37's? While it was sitting with a dead battery? If so did you reprogram your ECU for the new tire size?
So to go full cirlce - pull codes.
Last edited by kejtar; 10-30-2017 at 07:50 PM.
10-30-2017, 09:02 PM
#5
JK Enthusiast
Thread Starter
you got check engine light? pull codes - I'm betting money you have a gear ratio issue and you are in limp mode. You mentioned your battery died also. So here's a possibility - you have the right axles but the computer does not remember that you have 37's and it is seeing wrong rotation speed on the wheel sensor in relation the RPM's and speed and is deciding that something is wrong. Other option, the settings in the computer held but the axles are wrong.
Oh yeah, when did you upgrade the tires to 37's? While it was sitting with a dead battery? If so did you reprogram your ECU for the new tire size?
So to go full cirlce - pull codes.
Oh yeah, when did you upgrade the tires to 37's? While it was sitting with a dead battery? If so did you reprogram your ECU for the new tire size?
So to go full cirlce - pull codes.
How can I pull codes without it being drivable? I get off at 2:30am so in 2.5 hours, hoping it will magically act right and at least let me drive home. I don’t want to have to buy a programmer just for this.
But at least it seems like the tranny is fine and it’s a computer issue. I will be pissed if the axles are 3.21 though.
10-31-2017, 12:45 AM
#6
JK Enthusiast
Thread Starter
Update:
Got off work, started Jeep up, put it in reverse to back out of parking spot, had power. Drove home in what felt like 3rd gear again. Got home and started playing with it. It is behaving strangely.
If I start it up and go into drive, it moves (in 3rd gear) but once I take it out of drive after stopping, it loses power and just revs. Once I put it back into park, then back into drive or reverse, it has power again. So it will go from park to drive or reverse and move yet when I stop moving, and try to go from drive to reverse, or reverse to drive, it has no power and just revs and I have to go back into park then back to drive/reverse just to make it move again.
I did the key turn trick and tried to pull a code on the dash, yet it just showed the dash marks and then said "done" which apparently indicates that no codes are present. This is both good and bad. Im thinking my transmission is ok, but the computer is definitely screwy. Im beginning to think the guy I got the axles from either lied to me or didn't know better, he told me that 4 wheel parts stated to him that he had 3.73, but the Jeep seems to be in limp mode and seems due to nothing but the axle swap which indicates to me they are in fact 3.21, in which case they are essentially unusable for me and I will have wasted money for nothing. He is at SEMA 17 right now and so he couldn't send me his VIN for me to run on Jeep website to verify gear package.
The whole reason I just bought someones stock axles was to avoid having to reset the gears, I can learn to do it but its a messy process and just unbolting my axles and bolting in new ones was way simpler. I paid $1000 for the stock axles and I would've spent around $900 or so to buy the parts to change the gears in my blown up axles. If I did the work myself that is. I am building 1-tons and so I didn't see the use of buying aftermarket parts for stock sport axles.
Now if these are 3.21, I will have to put together my 14 bolt without the locker, find some kind of cheap wheels, and cut down a stock chevy driveshaft to use on it until I can buy an Adams and some matching Trail Ready beadlocks in 8 lug.
PAIN IN MY ASS.
Got off work, started Jeep up, put it in reverse to back out of parking spot, had power. Drove home in what felt like 3rd gear again. Got home and started playing with it. It is behaving strangely.
If I start it up and go into drive, it moves (in 3rd gear) but once I take it out of drive after stopping, it loses power and just revs. Once I put it back into park, then back into drive or reverse, it has power again. So it will go from park to drive or reverse and move yet when I stop moving, and try to go from drive to reverse, or reverse to drive, it has no power and just revs and I have to go back into park then back to drive/reverse just to make it move again.
I did the key turn trick and tried to pull a code on the dash, yet it just showed the dash marks and then said "done" which apparently indicates that no codes are present. This is both good and bad. Im thinking my transmission is ok, but the computer is definitely screwy. Im beginning to think the guy I got the axles from either lied to me or didn't know better, he told me that 4 wheel parts stated to him that he had 3.73, but the Jeep seems to be in limp mode and seems due to nothing but the axle swap which indicates to me they are in fact 3.21, in which case they are essentially unusable for me and I will have wasted money for nothing. He is at SEMA 17 right now and so he couldn't send me his VIN for me to run on Jeep website to verify gear package.
The whole reason I just bought someones stock axles was to avoid having to reset the gears, I can learn to do it but its a messy process and just unbolting my axles and bolting in new ones was way simpler. I paid $1000 for the stock axles and I would've spent around $900 or so to buy the parts to change the gears in my blown up axles. If I did the work myself that is. I am building 1-tons and so I didn't see the use of buying aftermarket parts for stock sport axles.
Now if these are 3.21, I will have to put together my 14 bolt without the locker, find some kind of cheap wheels, and cut down a stock chevy driveshaft to use on it until I can buy an Adams and some matching Trail Ready beadlocks in 8 lug.
PAIN IN MY ASS.
10-31-2017, 04:54 AM
#7
JK Jedi
Surely you're not building your 14b with 3.73 gearing, so you're gonna need to have a programmer at some point along the line. You may as well elevate that front axle and count the tire/DS revolutions as you turn one or the other and determine which gears are in there. It sounds mainly like a gearing issue and that they are not 3.73 after all......but should be easy to confirm one way or the other. If they are not the same as your stock gearing was, I'd just get programmer (that you'll prob need eventually anyhow) and program for those gears.....drive it for now and build your replacement axles.
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10-31-2017, 08:26 AM
#8
Ok, this sounds off..... stock tires are IIRC 225 75 16 which is 30". Going to 37's would require reprogramming as your wheel revs would have been off triggering limp mode. So either someone programmed the tires the first time around or you would have had issues from the get go as 30 to 37 (or even if yours came with 32's 32 to 37) is a huge jump that the computer would choke on.
Last edited by kejtar; 10-31-2017 at 08:59 AM.
10-31-2017, 09:38 AM
#9
JK Jedi
Ok, this sounds off..... stock tires are IIRC 225 75 16 which is 30". Going to 37's would require reprogramming as your wheel revs would have been off triggering limp mode. So either someone programmed the tires the first time around or you would have had issues from the get go as 30 to 37 (or even if yours came with 32's 32 to 37) is a huge jump that the computer would choke on.
10-31-2017, 09:58 AM
#10