Torque converter lockup question
Thread Starter
Staging Lane
Joined: Sep 2018
Posts: 58
Likes: 3
Torque converter lockup question So I just replaced the 4L60E in my Jeep with a 5.3 LS engine and the lockup has never worked since the swap. First I replaced the TCC solenoid and that didn't do anything. I hooked up a scan tool to it but not all of the functions work...one of those functions is of course TCC solenoid lockup enable/disable. I'm able to get information that makes me believe the electronics are working properly but the lockup isn't. I can get TCC duty cycle and TCC slip speed. On my jeep, the TCC duty cycle maxes out at 96% at speed and the slip speed will only get down to 50-75rpms when cruising. To make sure I know what I'm supposed to be seeing, I compared the data to my Chevy 2500 with 4L80E and the duty cycle cycle does go up to 100% and the slip speed goes down to 0-2rpms.
This makes me think the torque converter o-ring tore or fell off when installing the torque converter. Since I still have to get the trans jack back from a friend, I've got a little time anyway and thought I'd ask the question. Opinions?
This makes me think the torque converter o-ring tore or fell off when installing the torque converter. Since I still have to get the trans jack back from a friend, I've got a little time anyway and thought I'd ask the question. Opinions?
Thread Starter
Staging Lane
Joined: Sep 2018
Posts: 58
Likes: 3
I'll have to figure it out and see if I can.
I can check when I get home.
I can check when I get home.
TECH Fanatic
Joined: Oct 2014
Posts: 1,220
Likes: 179
From: Virginia
Both of us use HP Tuners, If I recall correctly (qweed), so that would be a great start. Some of the stock tables are very conservative in the tune. Also, are your TPS and VSS signals working properly? Could be another thing that could cause some issues. I know in my scanner, no matter WHAT I do, the MPH is off by about 15%. I used a GPS app to dial in my speedo, so it's DEAD on, however, the scanner still thinks it's about 15% slower than reality. I just compensate while knowing that in the tune. My WOT 4th gear shift occurs at 110 in the tune, when in reality I'm doing 130+. That's most likely a gear ratio offset, input vs output, and a lot of complicated math that actually explains it. Doesn't matter though, because I just know it's off. Nothing I can do about it. Pretty normal for older PCM's to get fooled lol.
But for your problem, it really sounds like the TCC is either:
1. Not getting the command to lock
or
2. Not getting enough pressure to lock
Could also be in the tune, but the RIGHT way to adjust the force motor is actually manually. TCC will typically lock in the 150 PSI range, up to 200. If it's higher, then it will smoke the crankshaft thrust bearing. Obviously, you need to check this with a gauge.
At the end of the day though, could just be a mechanical issue that you pointed out in your original post. Just trying to give you some other ideas, as all of us guys like to be able to try before having to face reality. I really hope it's something else, but not even you can be sure it is. Gotta love forums lol.
But for your problem, it really sounds like the TCC is either:
1. Not getting the command to lock
or
2. Not getting enough pressure to lock
Could also be in the tune, but the RIGHT way to adjust the force motor is actually manually. TCC will typically lock in the 150 PSI range, up to 200. If it's higher, then it will smoke the crankshaft thrust bearing. Obviously, you need to check this with a gauge.
At the end of the day though, could just be a mechanical issue that you pointed out in your original post. Just trying to give you some other ideas, as all of us guys like to be able to try before having to face reality. I really hope it's something else, but not even you can be sure it is. Gotta love forums lol.
Thread Starter
Staging Lane
Joined: Sep 2018
Posts: 58
Likes: 3
It's got enough pressure. About 60psi in D and neutral and it'll go up to around 150-180psi above about 45mph but the needle bounces a lot above 90 psi which is probably just my gauge setup. Reverse is around 80psi at idle and maybe 120psi with a little bit of gas.
The tune hasn't changed and the last transmission worked properly before it tanked. I'll probably yank it tomorrow and replace the o-ring for the torque converter. I'm getting good at pulling this trans at least....little victories? haha
The tune hasn't changed and the last transmission worked properly before it tanked. I'll probably yank it tomorrow and replace the o-ring for the torque converter. I'm getting good at pulling this trans at least....little victories? haha
Last edited by jfw432; Mar 30, 2019 at 05:58 PM.
TECH Fanatic
Joined: Oct 2014
Posts: 1,220
Likes: 179
From: Virginia
It's got enough pressure. About 60psi in D and neutral and it'll go up to around 150-180psi above about 45mph but the needle bounces a lot above 90 psi which is probably just my gauge setup. Reverse is around 80psi at idle and maybe 120psi with a little bit of gas.
The tune hasn't changed and the last transmission worked properly. I'll probably yank it tomorrow and replace the o-ring for the torque converter. I'm getting good at pulling this trans at least....little victories? haha
The tune hasn't changed and the last transmission worked properly. I'll probably yank it tomorrow and replace the o-ring for the torque converter. I'm getting good at pulling this trans at least....little victories? haha
The 60 uses a lock or unlock signal, not PWM, so it just might not be getting the signal to lock. I have the pinouts on my other computer, so I can't post them atm. Not sure if it could be a solenoid issue. Tough to say.
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Staging Lane
Joined: Sep 2018
Posts: 58
Likes: 3
Thread Starter
Staging Lane
Joined: Sep 2018
Posts: 58
Likes: 3
Well the TCC o-ring was pretty thin and looked worn out but it wasn't the problem unfortunately. For some reason I can't upload a photo or link to a photo so here is the pinout I found linked below. I verified the TCC solenoid worked prior to installing it in the trans. It looks like I could check the resistance between E and T for 20-40ohms and that would tell me that the solenoid is connected properly. I could splice into pin T and run a switch to it temporarily to determine if it's an electrical issue. I suspect pin T is a ground wire that but want to confirm with you guys.
https://wirings-diagram.com/wp-conte...am-728x946.jpg
https://wirings-diagram.com/wp-conte...am-728x946.jpg
Thread Starter
Staging Lane
Joined: Sep 2018
Posts: 58
Likes: 3
Nope. Never found the problem. I do have another wire harness I plan to throw in there but haven't gotten around to it yet. I was motivated to get it working properly but after dropping the transmission 5 times for various issues, I'm sick of it. It currently works without lock up and it's not my daily driver so a 10% loss in fuel economy when I'm getting 12mpg in a Jeep due to a slipping torque converter lock is not exactly a huge loss.
