4l60e Still Not Right After Rebuild - HELP PLEASE!!

[Sam Price]

Hey guys,

First post here, but have been reading the forums relentlessly trying to figure out what the hell is going on with my truck. If anyone has any advice, please don't hesitate to share. Thanks in advance.

My truck:
1998 Chevrolet K1500 4WD 5.7l V8 260k miles

About a month ago, I had my stock 4l60e stock transmission rebuilt by a reputable transmission shop in Washington State. The diagnosis was that the 3-4 clutches were shot and the transmission needed a full rebuild. I got my truck back, and pretty much right away, it seemed like it wasn't driving the way a truck with a rebuilt transmission should be driving. I took it to a different shop to get their opinion on it, and they said something was clearly still wrong. They pulled the transmission out of it and said they found an electrical issue that was causing the erratic shifting issues and I got it back a week later. The second shop told me that the rebuild looked good, there was just some minor electrical problem that had been overlooked during the rebuild, and now it was shifting through all the gears properly. Despite that, it still was not driving the way I expected/hoped. Here are some of the symptoms:

1. When cold or after sitting for a while it seems to drive the best/most consistent.
2. Seems to hunt for the proper gear especially between 3/4, erratically shifting between the two even when going a constant speed, leading to really low rpms + lack of power.
3. When accelerating uphill or under load, 1st through 3rd seem to shift mostly smooth, but when shifting from 3rd to 4th, I pretty much lose all acceleration and power right away.
4. When climbing a long steep hill in 4th gear, it will drop out of 4th gear into 3rd, sometimes even 2nd, and rev super high (yesterday, revved so high, blew a coolant line, spewing coolant all over my engine)
5. Shifts are mostly smooth, but do feel a slight delay/surge occasionally, and don't always seem to be occurring at the proper time.
6. Very slight shudder at idle.
7. Speedometer is off anywhere from 5-13 mph depending on what speed I'm going (recently replaced VSS on transfer case, so I know it's not this).
8. No CEL whatsoever, which seems kind of odd, not even after blowing my coolant line yesterday...

At this point, I'm convinced it has to be some sort of electrical issue, with the transmission not receiving the proper power or signals at the right time. In doing my research, I've found a few common issues, one of them being the ignition switch on the side of the steering column. I guess a lot of the wires that run power to the transmission run through that harness, and is a common failure point on these trucks. I've even read something like a faulty brake light switch can cause transmission problems as well. Maybe a bad PCM/ECU. I'm lost at this point.

If anyone has any advice about what might be the possible culprit, or need any other information to help determine what the issue might be, please reach out.

Thanks again,
Sam

 

[Oldblue98]

Hey guys,

First post here, but have been reading the forums relentlessly trying to figure out what the hell is going on with my truck. If anyone has any advice, please don't hesitate to share. Thanks in advance.

My truck:
1998 Chevrolet K1500 4WD 5.7l V8 260k miles

About a month ago, I had my stock 4l60e stock transmission rebuilt by a reputable transmission shop in Washington State. The diagnosis was that the 3-4 clutches were shot and the transmission needed a full rebuild. I got my truck back, and pretty much right away, it seemed like it wasn't driving the way a truck with a rebuilt transmission should be driving. I took it to a different shop to get their opinion on it, and they said something was clearly still wrong. They pulled the transmission out of it and said they found an electrical issue that was causing the erratic shifting issues and I got it back a week later. The second shop told me that the rebuild looked good, there was just some minor electrical problem that had been overlooked during the rebuild, and now it was shifting through all the gears properly. Despite that, it still was not driving the way I expected/hoped. Here are some of the symptoms:

1. When cold or after sitting for a while it seems to drive the best/most consistent.
2. Seems to hunt for the proper gear especially between 3/4, erratically shifting between the two even when going a constant speed, leading to really low rpms + lack of power.
3. When accelerating uphill or under load, 1st through 3rd seem to shift mostly smooth, but when shifting from 3rd to 4th, I pretty much lose all acceleration and power right away.
4. When climbing a long steep hill in 4th gear, it will drop out of 4th gear into 3rd, sometimes even 2nd, and rev super high (yesterday, revved so high, blew a coolant line, spewing coolant all over my engine)
5. Shifts are mostly smooth, but do feel a slight delay/surge occasionally, and don't always seem to be occurring at the proper time.
6. Very slight shudder at idle.
7. Speedometer is off anywhere from 5-13 mph depending on what speed I'm going (recently replaced VSS on transfer case, so I know it's not this).
8. No CEL whatsoever, which seems kind of odd, not even after blowing my coolant line yesterday...

At this point, I'm convinced it has to be some sort of electrical issue, with the transmission not receiving the proper power or signals at the right time. In doing my research, I've found a few common issues, one of them being the ignition switch on the side of the steering column. I guess a lot of the wires that run power to the transmission run through that harness, and is a common failure point on these trucks. I've even read something like a faulty brake light switch can cause transmission problems as well. Maybe a bad PCM/ECU. I'm lost at this point.

If anyone has any advice about what might be the possible culprit, or need any other information to help determine what the issue might be, please reach out.

Thanks again,
Sam

I went through pretty much all the same problems after having mine rebuilt.. Now I am not saying my problem is your problem, BUT you can spend a lot of time and money chasing your tail, I did ! The transmission shops rebuild transmissions but usually only clean up valve bodies.. If they even do that ! Mine turned out to be a worn valve bore that operates OD / 4 th gear. They usually ream and go with a over size valve in it.... BUT there is a valve kit that replaces that and uses a oversize o-ring . Long story short on mine roughly 3 grand later and tons of tail chasing a 30.00 kit and about 45 mins of my time cured the problem.. "In Mine"
I replaced sensors,switchs etc etc etc. The computer tries to compensate line psi when it is having errors and it does crazy things. I will look up the name and info on that kit and get back to you, and you can search it out

 

[Sam Price]

I went through pretty much all the same problems after having mine rebuilt.. Now I am not saying my problem is your problem, BUT you can spend a lot of time and money chasing your tail, I did ! The transmission shops rebuild transmissions but usually only clean up valve bodies.. If they even do that ! Mine turned out to be a worn valve bore that operates OD / 4 th gear. They usually ream and go with a over size valve in it.... BUT there is a valve kit that replaces that and uses a oversize o-ring . Long story short on mine roughly 3 grand later and tons of tail chasing a 30.00 kit and about 45 mins of my time cured the problem.. "In Mine"
I replaced sensors,switchs etc etc etc. The computer tries to compensate line psi when it is having errors and it does crazy things. I will look up the name and info on that kit and get back to you, and you can search it out

Great, thank you.

Yeah, at this point, I'm not ruling anything out so any additional information would be greatly appreciated.

I really appreciate your reply. Hopefully I can get this sorted out sooner than later.

Thanks again,
Sam

 

[Oldblue98]

Great, thank you.

Yeah, at this point, I'm not ruling anything out so any additional information would be greatly appreciated.

I really appreciate your reply. Hopefully I can get this sorted out sooner than later.

Thanks again,
Sam

Read up on this

xc_hide_links_from_guests_guests_error_hide_media

 

[Oldblue98]

Web page and info

http://www.fitzall.com/supportDetail.php?A74741Q-188

 

[Sam Price]

Web page and info

http://www.fitzall.com/supportDetail.php?A74741Q-188

Excellent, thank you.

I'll look into it right away. Their website, and most other sites say that is a fix for a specific code, P1870 I believe. I'm currently not throwing any codes, which is one of the weirdest parts about all this. Were you getting that or any other codes before you did this fix?

Thanks,
Sam

 

[Oldblue98]

Excellent, thank you.

I'll look into it right away. Their website, and most other sites say that is a fix for a specific code, P1870 I believe. I'm currently not throwing any codes, which is one of the weirdest parts about all this. Were you getting that or any other codes before you did this fix?

Thanks,
Sam

Mine was not coding either.. But it would start out cold, and shift through or not, then it would warm up and not do a fourth /OD shift or it would shutter... or it would do harsh 1-2 shifts like it had a shift kit in it... But the kicker was it might not always do the same thing twice in a row. But this fixed my problem and knock on wood has been the end of my transmission problem since I installed it.

 

[Oldblue98]

I replaced speed sensors,brake switch, TPS, played with coolant temps etc etc etc Kept going back to trans shop for warranty and he would say it was fixed and by the time I would drive off same thing again. I questioned the shop on the valve body and he said "Oh no we check that when rebuilding, yours was fine !! It was a very costly experience for sure.

 

[Sam Price]

I replaced speed sensors,brake switch, TPS, played with coolant temps etc etc etc Kept going back to trans shop for warranty and he would say it was fixed and by the time I would drive off same thing again. I questioned the shop on the valve body and he said "Oh no we check that when rebuilding, yours was fine !! It was a very costly experience for sure.

Aye Aye Aye,

Well, I just ordered that little TCC valve kit. In the meantime, I'm probably going to try changing out those sensors just to completely rule that out, as they're not terribly pricey. I'm going to get in touch with both transmission shops and ask them about that valve body, even though I'm expecting to hear the same thing that you heard.

Thanks again for the recommendation. This is my work truck (I deliver paddle boards and kayaks with it), and with the 4th of July just around the corner, I'm really hoping I can get this worked out ASAP or I'm going to be out a significant chunk of money

I'll let you know what I find out.

Sam

 

[Oldblue98]

Aye Aye Aye,

Well, I just ordered that little TCC valve kit. In the meantime, I'm probably going to try changing out those sensors just to completely rule that out, as they're not terribly pricey. I'm going to get in touch with both transmission shops and ask them about that valve body, even though I'm expecting to hear the same thing that you heard.

Thanks again for the recommendation. This is my work truck (I deliver paddle boards and kayaks with it), and with the 4th of July just around the corner, I'm really hoping I can get this worked out ASAP or I'm going to be out a significant chunk of money

I'll let you know what I find out.

Sam

Good luck in your journey =) I know I am old school and back in the day when a transmission puked you rebuilt it and life was good, today's time the transmission itself is but a small part of the problem ! There is so many elect sensors, wires, harness, computer ... it is mind blowing when you are at the mercy of a shop that wants to sell rebuilds.