4L60e Intermittent second gear
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4L60e Intermittent second gear 1997 K1500 suburban
I just finished rebuilding the transmission and put back in around May of this year.(I've been working on it since Sept, it took me awhile.)
It seemed to run fine, but it's my wife's rig so I don't get much time behind the wheel.
Saturday I noticed it was sluggish from a start. I got it on the highway and it's doing ~3500 rpm for 55mph. I played with it a bit and realized it was stuck in 2nd gear. My wife says "yeah, it's been doing this sometimes".
Why the hell not mention it? Questions about how often, when did it start, and if there were any contributing factors are met with a shrug.
Starts off in second gear and stays in second gear.
Speedometer works fine.
I can get first gear if I manually select it.
The trip involved some 4WD low and IIRC it seemed to go through all the gears while in 4 low. I want to re-verify that.
I would think it's a solenoid, but I thought limp mode is 3rd gear.
I would suspect the speed sensor but my speedometer works fine. I did test the resistance of the output speed sensor. It's reading 1553 ohms, which is outside the ATSG manuals specs by 13 ohms. I figured that's just because it was hot out. Ambient air temp was 104F when I tested it.
I tried to get it to act up again later that evening so I could test it in 4WD Low but it behaved.
It has ABS, maybe the speedometer is getting the speed from the wheels? Though I didn't think a 97 did that.
So... I'm thinking when it gets really hot out, the resistance of the speed sensor goes out of range and causes this issue?
What do you guys think?
I just finished rebuilding the transmission and put back in around May of this year.(I've been working on it since Sept, it took me awhile.)
It seemed to run fine, but it's my wife's rig so I don't get much time behind the wheel.
Saturday I noticed it was sluggish from a start. I got it on the highway and it's doing ~3500 rpm for 55mph. I played with it a bit and realized it was stuck in 2nd gear. My wife says "yeah, it's been doing this sometimes".
Why the hell not mention it? Questions about how often, when did it start, and if there were any contributing factors are met with a shrug.Starts off in second gear and stays in second gear.
Speedometer works fine.
I can get first gear if I manually select it.
The trip involved some 4WD low and IIRC it seemed to go through all the gears while in 4 low. I want to re-verify that.
I would think it's a solenoid, but I thought limp mode is 3rd gear.
I would suspect the speed sensor but my speedometer works fine. I did test the resistance of the output speed sensor. It's reading 1553 ohms, which is outside the ATSG manuals specs by 13 ohms. I figured that's just because it was hot out. Ambient air temp was 104F when I tested it.
I tried to get it to act up again later that evening so I could test it in 4WD Low but it behaved.
It has ABS, maybe the speedometer is getting the speed from the wheels? Though I didn't think a 97 did that.
So... I'm thinking when it gets really hot out, the resistance of the speed sensor goes out of range and causes this issue?
What do you guys think?
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I found this gem on page 80 of the ATSG Update manual for the 4L60E.
"COMPLAINT: Before and/or after rebuild the vehicle exhibits a 2nd gear start with only a 2-3 shift and possibly a lack of proper line pressure rise with throttle opening."
"CAUSE: The cause may be, one or both of the screens in the spacer plate collapsed shut, and restricting solenoid feed oil or actuator feed oil to the Pressure Control Solenoid."
I definitely had trouble with those screens. There was a spacer that fell out the last time I dropped the valve body and I don't remember if I got it back in.(I have a torn rotator cuff, holding a valve body up in place under the transmission hurts like hell.) I also don't think there are holes drilled in the new ones. I looked at the old ones last night and they do have holes drilled in them. I'll check them this weekend and report back.
"COMPLAINT: Before and/or after rebuild the vehicle exhibits a 2nd gear start with only a 2-3 shift and possibly a lack of proper line pressure rise with throttle opening."
"CAUSE: The cause may be, one or both of the screens in the spacer plate collapsed shut, and restricting solenoid feed oil or actuator feed oil to the Pressure Control Solenoid."
I definitely had trouble with those screens. There was a spacer that fell out the last time I dropped the valve body and I don't remember if I got it back in.(I have a torn rotator cuff, holding a valve body up in place under the transmission hurts like hell.) I also don't think there are holes drilled in the new ones. I looked at the old ones last night and they do have holes drilled in them. I'll check them this weekend and report back.
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I got impatient and pulled the screens last night. I got on the interstate and all was good for about two or three miles and then it dropped into second again. I played with it quite a bit trying to get a feel for what was going on.
Unlike putting the shift selector in "2", the car is able to coast when it gets stuck. So I can get it up to 60mph, let off the gas and coast.
I pulled over, shut everything off and restarted. It still started off and stayed in 2nd gear.
I had wanted to check to see if 4Lo still went through all the gear ranges. Before I did that I wanted to check 4Hi. When I put it in 4Hi, it drove correctly. It went through all the gears. It stayed right even after I put it back in 2WD.
I mentioned it to my wife and she said "Yeah, it didn't start happening until after you fixed the 4WD". So, info on what I did with the 4WD. The thermal actuator died, so I decided to replace it with a motorized actuator. They don't just plug in, the old one takes a 2 pin connector, the new one takes a five pin. I wired it up wrong the first time. Maybe I damaged something? I think it's odd that engaging the 4WD makes things work again. Maybe it's just coincidence?
I think I'm going to unplug the 4WD actuator and see if the problem crops up again.
Unlike putting the shift selector in "2", the car is able to coast when it gets stuck. So I can get it up to 60mph, let off the gas and coast.
I pulled over, shut everything off and restarted. It still started off and stayed in 2nd gear.
I had wanted to check to see if 4Lo still went through all the gear ranges. Before I did that I wanted to check 4Hi. When I put it in 4Hi, it drove correctly. It went through all the gears. It stayed right even after I put it back in 2WD.
I mentioned it to my wife and she said "Yeah, it didn't start happening until after you fixed the 4WD". So, info on what I did with the 4WD. The thermal actuator died, so I decided to replace it with a motorized actuator. They don't just plug in, the old one takes a 2 pin connector, the new one takes a five pin. I wired it up wrong the first time. Maybe I damaged something? I think it's odd that engaging the 4WD makes things work again. Maybe it's just coincidence?
I think I'm going to unplug the 4WD actuator and see if the problem crops up again.
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I disconnected the actuator and there was no change. It seems that switching to 4WD only helped for a little while, or it was entirely coincidental.
I hear there is a speed related component behind the glovebox. Is that true? I can't find any info that says a 1997 has one there.
Any ideas on what could cause intermittent second gear starts?
I hear there is a speed related component behind the glovebox. Is that true? I can't find any info that says a 1997 has one there.
Any ideas on what could cause intermittent second gear starts?
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From: Ann Arbor, MI
I'm sorry that no one has been posting to help you. Perhaps one of the pros has some ideas because I have no experience with this and don't remember anyone else posting the same symptoms and later the fix.
When you wrote "there was a spacer that fell out the last time I dropped the valve body" did you mean a filter screen?
The Transgo HD2 kit recommends drilling tiny holes into the top plastic of the filter screens; so perhaps this was done during an earlier rebuild.
When you wrote "there was a spacer that fell out the last time I dropped the valve body" did you mean a filter screen?
The Transgo HD2 kit recommends drilling tiny holes into the top plastic of the filter screens; so perhaps this was done during an earlier rebuild.
Last edited by mrvedit; Jul 17, 2017 at 09:42 PM.
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Hi mrvedit,
Thanks!
This is the second time I've rebuilt this transmission. Last time I put in a Transgo HD2 kit. It was part of a larger kit from Dana at Probuilt.
Part of the Transgo kit included a gold spacer(looks like a safety pin that was cut in half) for the larger of the two valve body screens to keep it from collapsing. It was still in place though when I took out the screens the other day though. I still have the old filter screens with the holes drilled in the plastic.
Speaking of which, I found the cone shaped screen from the TCC valve in the trans filter. The new valve I put in didn't have a way to lock in the screen.
Thanks!
This is the second time I've rebuilt this transmission. Last time I put in a Transgo HD2 kit. It was part of a larger kit from Dana at Probuilt.
Part of the Transgo kit included a gold spacer(looks like a safety pin that was cut in half) for the larger of the two valve body screens to keep it from collapsing. It was still in place though when I took out the screens the other day though. I still have the old filter screens with the holes drilled in the plastic.
Speaking of which, I found the cone shaped screen from the TCC valve in the trans filter. The new valve I put in didn't have a way to lock in the screen.
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Now I assume you mean the tiny screen in the TCC solenoid?
I wouldn't worry about that.
Else, tell me the part # from the ATSG manual.
Did you follow Step 5, Page 2 of the Transgo HD2 instructions to replace the 1-2 Shift valve?
I'm not a fan of this "Gear Command" feature as it would let you accidentally downshift too far and blow the engine. If you still have the original 1-2 shift valve, you might try re-installing that and removing the Transgo shift valve, gold ball and green spring. Granted I'm grasping for straws here and guessing, but unless/until a pro jumps in here with a more likely solution, it is what I would do myself.
I wouldn't worry about that.
Else, tell me the part # from the ATSG manual.
Did you follow Step 5, Page 2 of the Transgo HD2 instructions to replace the 1-2 Shift valve?
I'm not a fan of this "Gear Command" feature as it would let you accidentally downshift too far and blow the engine. If you still have the original 1-2 shift valve, you might try re-installing that and removing the Transgo shift valve, gold ball and green spring. Granted I'm grasping for straws here and guessing, but unless/until a pro jumps in here with a more likely solution, it is what I would do myself.
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A '97 model CPSI GMT400 would NOT have a VSS Buffer/DRAC module like the earlier pre-'96 TBI GMT400's
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Now I assume you mean the tiny screen in the TCC solenoid?
I wouldn't worry about that.
Else, tell me the part # from the ATSG manual.
Did you follow Step 5, Page 2 of the Transgo HD2 instructions to replace the 1-2 Shift valve?
I'm not a fan of this "Gear Command" feature as it would let you accidentally downshift too far and blow the engine. If you still have the original 1-2 shift valve, you might try re-installing that and removing the Transgo shift valve, gold ball and green spring. Granted I'm grasping for straws here and guessing, but unless/until a pro jumps in here with a more likely solution, it is what I would do myself.
I wouldn't worry about that.
Else, tell me the part # from the ATSG manual.
Did you follow Step 5, Page 2 of the Transgo HD2 instructions to replace the 1-2 Shift valve?
I'm not a fan of this "Gear Command" feature as it would let you accidentally downshift too far and blow the engine. If you still have the original 1-2 shift valve, you might try re-installing that and removing the Transgo shift valve, gold ball and green spring. Granted I'm grasping for straws here and guessing, but unless/until a pro jumps in here with a more likely solution, it is what I would do myself.
I doubt I still have the original 1-2 shift valve. This is the second rebuild I've done on it. I put the HD2 kit in back in 2010 when my 3/4 clutches toasted. I foolishly chucked all the old parts. I'm keeping stuff this time around. Especially the clutches and steels since the ones I put in back in 2010 looked new. As for your ideas, I will definitely check them. I don't remember the gold ball and green spring, but it has been awhile. I kept the instructions for the HD2 kit so I can see what I did.
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I wish I could tell what the solenoid state was or the gear the pcm/tcm is commanding. I don't have a good scan tool. I have been trying to find one and started another thread here yesterday asking for advice on picking one.
I do have a local trans shop that has helped me out with odds and ends. I trust them. I've been considering going to them with this problem. I would feel like a jerk taking my screw up to them but I'm desperate. LOL.
It wouldn't start yesterday. Turns out the battery was weak. Gave 12.4 volts but wouldn't give enough amps to run the starter. I also cleaned off the VSS. It had some metal shavings stuck to it. I rerouted the shift cable away from the transfer case linkage too. Maybe one of those three things will fix it. I'll know this afternoon.
If it doesn't fix it, I'm going to pull the valve body again this weekend, completely disassemble and clean it out, recheck the shift solenoids, and take a close look at 1-2 shift valve.
Thank you guys for giving suggestions.
I do have a local trans shop that has helped me out with odds and ends. I trust them. I've been considering going to them with this problem. I would feel like a jerk taking my screw up to them but I'm desperate. LOL.
It wouldn't start yesterday. Turns out the battery was weak. Gave 12.4 volts but wouldn't give enough amps to run the starter. I also cleaned off the VSS. It had some metal shavings stuck to it. I rerouted the shift cable away from the transfer case linkage too. Maybe one of those three things will fix it. I'll know this afternoon.
If it doesn't fix it, I'm going to pull the valve body again this weekend, completely disassemble and clean it out, recheck the shift solenoids, and take a close look at 1-2 shift valve.
Thank you guys for giving suggestions.
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From: Fort Worth, Texas
I wish I could tell what the solenoid state was or the gear the pcm/tcm is commanding. I don't have a good scan tool. I have been trying to find one and started another thread here yesterday asking for advice on picking one.
I do have a local trans shop that has helped me out with odds and ends. I trust them. I've been considering going to them with this problem. I would feel like a jerk taking my screw up to them but I'm desperate. LOL.
It wouldn't start yesterday. Turns out the battery was weak. Gave 12.4 volts but wouldn't give enough amps to run the starter. I also cleaned off the VSS. It had some metal shavings stuck to it. I rerouted the shift cable away from the transfer case linkage too. Maybe one of those three things will fix it. I'll know this afternoon.
If it doesn't fix it, I'm going to pull the valve body again this weekend, completely disassemble and clean it out, recheck the shift solenoids, and take a close look at 1-2 shift valve.
Thank you guys for giving suggestions.
I do have a local trans shop that has helped me out with odds and ends. I trust them. I've been considering going to them with this problem. I would feel like a jerk taking my screw up to them but I'm desperate. LOL.
It wouldn't start yesterday. Turns out the battery was weak. Gave 12.4 volts but wouldn't give enough amps to run the starter. I also cleaned off the VSS. It had some metal shavings stuck to it. I rerouted the shift cable away from the transfer case linkage too. Maybe one of those three things will fix it. I'll know this afternoon.
If it doesn't fix it, I'm going to pull the valve body again this weekend, completely disassemble and clean it out, recheck the shift solenoids, and take a close look at 1-2 shift valve.
Thank you guys for giving suggestions.
The Snap-On MT2500 "Red Brick" Scanner with a 1999 or 2001 Domestic Primary Cartridge & a 1996 & later Trouble-Shooter Cartridge is a VERY powerful diagnostic scan tool that is second ONLY to a GM Tech 2 for your specific year model.
A MT2500 body, 2001 Primary/2001 TS Cartridges, Cable, OBD 2 adapter, & a K9 personality Key is worth about $200 in MINT condition.
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Thank you Clinebarger, and mrvedit!
I'm more than likely going to get one of the bricks. I have a 91 corolla and a 92 E-350, both OBD-I, and the brick can do OBD-I.
I have a lot to learn about the brick before I get one to make sure I get the right stuff for it.
mrvedit, thank you so much for the offer. If I need the 1-2 valve, I can wait until you are back to have it sent. I've been fighting this trans since it died
The problem didn't manifest yesterday on a trip it would normally show up for. I'm not ready to say "fixed", but I'm hoping.
I'm more than likely going to get one of the bricks. I have a 91 corolla and a 92 E-350, both OBD-I, and the brick can do OBD-I.
I have a lot to learn about the brick before I get one to make sure I get the right stuff for it.
mrvedit, thank you so much for the offer. If I need the 1-2 valve, I can wait until you are back to have it sent. I've been fighting this trans since it died
The problem didn't manifest yesterday on a trip it would normally show up for. I'm not ready to say "fixed", but I'm hoping.
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It's been a week of daily driving and the problem hasn't happened again.
I'm left scratching my head, not being able to figure out what the problem was.
If it were the battery, why would it drive fine for the first 10 or 15 minutes?
If it were the VSS, why did the speedometer work fine?
If it was the cable I moved, why (once again) did it drive fine for the first 10 or 15 minutes?
Maybe it was some combination of the above?
So I would say, if someone else has a similar problem, clean off the VSS and if that doesn't fix it, get the battery tested.
I'm left scratching my head, not being able to figure out what the problem was.
If it were the battery, why would it drive fine for the first 10 or 15 minutes?
If it were the VSS, why did the speedometer work fine?
If it was the cable I moved, why (once again) did it drive fine for the first 10 or 15 minutes?
Maybe it was some combination of the above?
So I would say, if someone else has a similar problem, clean off the VSS and if that doesn't fix it, get the battery tested.