No 2-3 shift at WOT ***SOLVED***
10-12-2017, 09:43 AM
#61
Ok if you don’t manually shift then scratch the hd 2-3 valve. The billet 2nd gear is more worth it than getting the 4th gear one. How often do you run wot in 4th? How often do you run wot in 2nd? Probably a good bit more than 4th.
So this is what I’d get with where your at. Gpz 3-4 clutches. They cost the same as high energy ones. Wide band. New molded pistons and change the green oring. Tighten your 3-4 clearance and band clearance while it’s apart. If you opt to not get the billet 2nd servo then get the longer sonnax pin with seals on it and adjust your clearance to .075ish with that. The hd pump spring you need that too. .500 boost valve.
Also check your Checkball in the 2-4 servo bore or leakage. That’s very important too.
If you want to be sure or have any doubt, replace the Teflon seals. Just an FYI, I don’t use trans go anything. Pretty much have had nothing but problems with their shift kits and stuff. It changes the shift timing too much and your left chasing your tail.
I try to stick to my ideology with what I do. Think of things this way, how long does a brand new trans last? Over 100k miles and many years. If you deviate too far off from its original design and calibration then you cause yourself more problems than you fix. So in a nutshell what I do is fix the major leaks, upgrade clutches, upgrade the sun shell as it’s known to fail and reinforce the aluminum splined area on the input drum. I usually don’t drill separator plate or drill holes in the valve body and change valves in the valve body except for the hd 2-3 valve which is a sonnax product anyways. If you tighten clearances too much then clutches drag and wear prematurely. If you remove the 3-4 release springs the clutches will drag and wear prematurely. Keep it simple.
So this is what I’d get with where your at. Gpz 3-4 clutches. They cost the same as high energy ones. Wide band. New molded pistons and change the green oring. Tighten your 3-4 clearance and band clearance while it’s apart. If you opt to not get the billet 2nd servo then get the longer sonnax pin with seals on it and adjust your clearance to .075ish with that. The hd pump spring you need that too. .500 boost valve.
Also check your Checkball in the 2-4 servo bore or leakage. That’s very important too.
If you want to be sure or have any doubt, replace the Teflon seals. Just an FYI, I don’t use trans go anything. Pretty much have had nothing but problems with their shift kits and stuff. It changes the shift timing too much and your left chasing your tail.
I try to stick to my ideology with what I do. Think of things this way, how long does a brand new trans last? Over 100k miles and many years. If you deviate too far off from its original design and calibration then you cause yourself more problems than you fix. So in a nutshell what I do is fix the major leaks, upgrade clutches, upgrade the sun shell as it’s known to fail and reinforce the aluminum splined area on the input drum. I usually don’t drill separator plate or drill holes in the valve body and change valves in the valve body except for the hd 2-3 valve which is a sonnax product anyways. If you tighten clearances too much then clutches drag and wear prematurely. If you remove the 3-4 release springs the clutches will drag and wear prematurely. Keep it simple.
10-12-2017, 09:50 AM
#62
You may have already done something like this, But I would suggest you consider tying an 12v led to the yellow wire with black stripe in harness, positive side to the wire negative side to ground, this will give a true real time indication of shift command (must be led not test light unless it is led) this LED will be on in 1st off in 2nd on in 3rd I think this would help in searching for this issue , Yes I know your scanner/ tuner shows this in display but I have found its not always true or delayed on a couple occasions working with people dealing with this type issue. If you have done this then all good but can be a very helpful tool when diagnosing shift timing issues.
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10-12-2017, 10:05 AM
#64
You may have already done something like this, But I would suggest you consider tying an 12v led to the yellow wire with black stripe in harness, positive side to the wire negative side to ground, this will give a true real time indication of shift command (must be led not test light unless it is led) this LED will be on in 1st off in 2nd on in 3rd I think this would help in searching for this issue , Yes I know your scanner/ tuner shows this in display but I have found its not always true or delayed on a couple occasions working with people dealing with this type issue. If you have done this then all good but can be a very helpful tool when diagnosing shift timing issues.
10-12-2017, 11:35 AM
#66
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Parts ordered.
before I pull the pistons out, do you think I should air test them and listen for leaks? Also, I'm wondering if I should replace the reverse piston, or leave it alone. I'm thinking it may not be affected.
but on the other hand, I would hate to go through all this work and miss that one thing.
before I pull the pistons out, do you think I should air test them and listen for leaks? Also, I'm wondering if I should replace the reverse piston, or leave it alone. I'm thinking it may not be affected.
but on the other hand, I would hate to go through all this work and miss that one thing.
Last edited by Reserector; 10-12-2017 at 12:28 PM.
10-12-2017, 01:35 PM
#68
TECH Addict
Parts ordered.
before I pull the pistons out, do you think I should air test them and listen for leaks? Also, I'm wondering if I should replace the reverse piston, or leave it alone. I'm thinking it may not be affected.
but on the other hand, I would hate to go through all this work and miss that one thing.
before I pull the pistons out, do you think I should air test them and listen for leaks? Also, I'm wondering if I should replace the reverse piston, or leave it alone. I'm thinking it may not be affected.
but on the other hand, I would hate to go through all this work and miss that one thing.
10-12-2017, 10:24 PM
#69
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Thanks for that link. I had some time this evening to dig into this.
I've done most of those tests, now, and so far no problems. I'm taking my time, trying to be thorough.
Fingers crossed that I will find causes that I can fix, and have confidence in this build.
I've done most of those tests, now, and so far no problems. I'm taking my time, trying to be thorough.
Fingers crossed that I will find causes that I can fix, and have confidence in this build.
Last edited by Reserector; 10-13-2017 at 06:01 AM.
10-15-2017, 06:29 PM
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I got as far as I could. Waiting for the new overrun clutch hub do I can finish up the internals.
My suspicion regarding the worn brass on the sprag is that during a previous build, the overrun hub only engaged one of the two frictions, putting the assembly in a bind for a while, and causing massive wear.
So far, the only other suspicious thing I found was some steel grit between the overrun piston and the forward clutch piston (they fit together) that could have compromised the overrun piston seal, but I highly doubt that caused my problem. There was fine grit stuck to the piston seal, but it air tested ok.
I'll be watching for more contamination as I go. Especially in the valve body.
I suspect the grit was from the stripped sun shell, and somehow didn't get cleaned out. Or maybe it came from the pump when I broke the rotor. I don't know how either could have gotten there, but it did.
My suspicion regarding the worn brass on the sprag is that during a previous build, the overrun hub only engaged one of the two frictions, putting the assembly in a bind for a while, and causing massive wear.
So far, the only other suspicious thing I found was some steel grit between the overrun piston and the forward clutch piston (they fit together) that could have compromised the overrun piston seal, but I highly doubt that caused my problem. There was fine grit stuck to the piston seal, but it air tested ok.
I'll be watching for more contamination as I go. Especially in the valve body.
I suspect the grit was from the stripped sun shell, and somehow didn't get cleaned out. Or maybe it came from the pump when I broke the rotor. I don't know how either could have gotten there, but it did.
10-22-2017, 02:45 PM
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All of my transmission problems are solved. No, I didn't sell it, crash it, nor did I replace it. I did a successful, complete rebuild, and it works perfectly in every respect.
Here is a summary of this thread, and my conclusions.
I started this thread to find out why my 4L60E wouldn't shift from 2-3 under heavy throttle. But that's not the beginning of the story, so let's back up.
I bought a 2000 Silverado to dismantle and stuff into my '86 Hardbody 4x4. It had high mileage, and a mystery transmission. All I know about it is that it is a 2001 model that has the correct codes to match my requirements. (5.3 LM7 4x4) Unknown mileage.
The trans would fall out of gear, and the speedo would jump at random times. I solved that problem by re-doing ALL of the grounding points on the truck. It had a flare during the 2-3 shift under heavy throttle, but worked well otherwise.
Next, the whole shebang got shoehorned into my Hardbody and ran the same until one fateful day when the sun shell stripped.
I dropped the trans, ordered a kit, and used the transmissionbench.com videos to rebuild it. I also replaced a worn planet gear, and all of the bushings. New pistons and band as well. Reman torque converter, since it has a clutch. I did NOT replace the drum (it was still in good condition) or the forward sprag, even though the sprag had a badly worn brass outer ring, and there was matching wear on the overrun clutch hub. I reasoned that if it was working before the shell stripped, that it would continue to work. Logic, right?
Here's where it went wrong:
During installation, I was bolting up the bell housing to the block and heard a POP!. I was suspecious, but told myself that it was the housing going onto the dowel pins. There were a couple more pops, but it bolted up.
Turns out that the pops were the pump rotor breaking. When I started the truck I had nothing. Zero. Zilch.
I ordered a reman pump on eBay and swapped it in. Started the truck and it worked, but there was a worrisome delay when shifted into forward or reverse. It shifted ok, but when I came to a stop, there was a delay when pulling forward, followed by a lurch when it "caught". I test ran it, and then parked it until I figured out what was wrong. The pressure at idle was 25, but why? (Normal is 55)
Get this; the reman pump, which came with new gasket and o-ring, did NOT come with a filter screen and it's o-ring. I assumed it was ready to install, so I never noticed. Imagine my joy when I found out that I was losing pressure because of this omission, and I would have to drop the trans AGAIN.
I pulled the trans and the pump, and installed the screen. (Now pay attention to this) The trans was laying with the valve body up when I reinstalled the pump. I had some trouble getting it to start into the case, but once it started, I was able to pull it in with the bolts. (I know now NOT to do that. I should have stood it on end.) Hindsight, right?
After installing it, it slipped, wouldn't shift right, drug in some gears... it was all screwed up. Using the addage that the first thing to check is the last thing you fixed, I pulled the trans again, and after pulling the pump, I saw that the band had come off of its anchor pin. DOH!
Simple fix; put it back on the pin, stand it up, and install the pump.
This time, the transmission worked... except the 2-3 shift under heavy throttle. Also, the pressure was slightly low. (50 instead of 55) I tried programming it out, to no avail. I went through the valve body to check for stuck valves, and to install every aftermarket upgrade that I could.
I lived with the shifting problem for months until it started to slip out of 4th on the highway under light throttle. Increased throttle would build more pressure and it would go back into gear.
This time, I left nothing to chance. I replaced the input (band) drum, the worn sprag, and all of the frictions, steels, pistons, and soft parts. I upgraded the 4th apply piston to the superior billet one that has a larger area, and lip seal. I did this to make it hold up better when towing in 4th.
My findings were not conclusive or convincing. My clearances were in spec. The clutches were like new, so I will save them to use in my next rebuild. No damaged seals or pistons. I found some grit between the overrun piston and the forward piston that it slides in, but again, this would not cause either of my problems. Besides, everything air tested just fine.
I took the time to replace all of the teflon rings on the pump stator and input shaft this time.
My conclusion, and educated suspicions:
I strongly feel that in spite of the teflon rings LOOKING good, I think that they were made thinner by the side load on the shaft when the band fell off the anchor pin, and I forced the pump back in. I believe that the side load made the cross section of the rings thinner. When the situation was corrected, the rings allowed fluid to bypass into adjacent sections. This is the only logical explanation for all of my symptoms.
Now, the transmission runs perfectly. It shifts buttery smooth at low throttle, yet throws you back in the seat under full throttle with not slamming. I've never felt it work so well!
So there you have it. The comedy of errors that haunted my existence for several months. This chapter is closed, and my confidence is restored. I now have most everything I need for my next overhaul, which I hope will not be for several years, now.
I would like to thank all of you who took the time to lend your insight and thoughts. You've been a huge help. I now have a upgraded 4L60E that I am confident will meet my needs for a long time.
Lessons learned:
1. Make sure the torque converter goes in three clicks. Check it by rotating it often as you install the trans to make sure it is not in a bind. If the bell housing does not seat easily, do not force it in the least.
2. If you replace a pump, make sure it is complete with filter screen (with o-ring), bost valve, etc. Do not assume it is ready to install.
3. Stand the unit on its end when installing the pump, and make sure the band is on its anchor pin. A misaligned drum and input shaft can ruin the teflon rings in a way that is not obvious, leading to pressuure loss and bleed-over.
4. Never give up. Persevere and use logic to figure it out. What are the facts?
Here is a summary of this thread, and my conclusions.
I started this thread to find out why my 4L60E wouldn't shift from 2-3 under heavy throttle. But that's not the beginning of the story, so let's back up.
I bought a 2000 Silverado to dismantle and stuff into my '86 Hardbody 4x4. It had high mileage, and a mystery transmission. All I know about it is that it is a 2001 model that has the correct codes to match my requirements. (5.3 LM7 4x4) Unknown mileage.
The trans would fall out of gear, and the speedo would jump at random times. I solved that problem by re-doing ALL of the grounding points on the truck. It had a flare during the 2-3 shift under heavy throttle, but worked well otherwise.
Next, the whole shebang got shoehorned into my Hardbody and ran the same until one fateful day when the sun shell stripped.
I dropped the trans, ordered a kit, and used the transmissionbench.com videos to rebuild it. I also replaced a worn planet gear, and all of the bushings. New pistons and band as well. Reman torque converter, since it has a clutch. I did NOT replace the drum (it was still in good condition) or the forward sprag, even though the sprag had a badly worn brass outer ring, and there was matching wear on the overrun clutch hub. I reasoned that if it was working before the shell stripped, that it would continue to work. Logic, right?
Here's where it went wrong:
During installation, I was bolting up the bell housing to the block and heard a POP!. I was suspecious, but told myself that it was the housing going onto the dowel pins. There were a couple more pops, but it bolted up.
Turns out that the pops were the pump rotor breaking. When I started the truck I had nothing. Zero. Zilch.
I ordered a reman pump on eBay and swapped it in. Started the truck and it worked, but there was a worrisome delay when shifted into forward or reverse. It shifted ok, but when I came to a stop, there was a delay when pulling forward, followed by a lurch when it "caught". I test ran it, and then parked it until I figured out what was wrong. The pressure at idle was 25, but why? (Normal is 55)
Get this; the reman pump, which came with new gasket and o-ring, did NOT come with a filter screen and it's o-ring. I assumed it was ready to install, so I never noticed. Imagine my joy when I found out that I was losing pressure because of this omission, and I would have to drop the trans AGAIN.
I pulled the trans and the pump, and installed the screen. (Now pay attention to this) The trans was laying with the valve body up when I reinstalled the pump. I had some trouble getting it to start into the case, but once it started, I was able to pull it in with the bolts. (I know now NOT to do that. I should have stood it on end.) Hindsight, right?
After installing it, it slipped, wouldn't shift right, drug in some gears... it was all screwed up. Using the addage that the first thing to check is the last thing you fixed, I pulled the trans again, and after pulling the pump, I saw that the band had come off of its anchor pin. DOH!
Simple fix; put it back on the pin, stand it up, and install the pump.
This time, the transmission worked... except the 2-3 shift under heavy throttle. Also, the pressure was slightly low. (50 instead of 55) I tried programming it out, to no avail. I went through the valve body to check for stuck valves, and to install every aftermarket upgrade that I could.
I lived with the shifting problem for months until it started to slip out of 4th on the highway under light throttle. Increased throttle would build more pressure and it would go back into gear.
This time, I left nothing to chance. I replaced the input (band) drum, the worn sprag, and all of the frictions, steels, pistons, and soft parts. I upgraded the 4th apply piston to the superior billet one that has a larger area, and lip seal. I did this to make it hold up better when towing in 4th.
My findings were not conclusive or convincing. My clearances were in spec. The clutches were like new, so I will save them to use in my next rebuild. No damaged seals or pistons. I found some grit between the overrun piston and the forward piston that it slides in, but again, this would not cause either of my problems. Besides, everything air tested just fine.
I took the time to replace all of the teflon rings on the pump stator and input shaft this time.
My conclusion, and educated suspicions:
I strongly feel that in spite of the teflon rings LOOKING good, I think that they were made thinner by the side load on the shaft when the band fell off the anchor pin, and I forced the pump back in. I believe that the side load made the cross section of the rings thinner. When the situation was corrected, the rings allowed fluid to bypass into adjacent sections. This is the only logical explanation for all of my symptoms.
Now, the transmission runs perfectly. It shifts buttery smooth at low throttle, yet throws you back in the seat under full throttle with not slamming. I've never felt it work so well!
So there you have it. The comedy of errors that haunted my existence for several months. This chapter is closed, and my confidence is restored. I now have most everything I need for my next overhaul, which I hope will not be for several years, now.
I would like to thank all of you who took the time to lend your insight and thoughts. You've been a huge help. I now have a upgraded 4L60E that I am confident will meet my needs for a long time.
Lessons learned:
1. Make sure the torque converter goes in three clicks. Check it by rotating it often as you install the trans to make sure it is not in a bind. If the bell housing does not seat easily, do not force it in the least.
2. If you replace a pump, make sure it is complete with filter screen (with o-ring), bost valve, etc. Do not assume it is ready to install.
3. Stand the unit on its end when installing the pump, and make sure the band is on its anchor pin. A misaligned drum and input shaft can ruin the teflon rings in a way that is not obvious, leading to pressuure loss and bleed-over.
4. Never give up. Persevere and use logic to figure it out. What are the facts?
Last edited by Reserector; 10-22-2017 at 02:53 PM.
10-22-2017, 05:22 PM
#73
TECH Senior Member
comment on lesson #1:
with the converter all the way in, measure how far past the bell-to-engine mating surface the converter bolt pad is.
comment on lesson #3:
I think teflon rings are way too soft and deform easily for any number of reasons... I think they should be replaced any time they are exposed.
with the converter all the way in, measure how far past the bell-to-engine mating surface the converter bolt pad is.
comment on lesson #3:
I think teflon rings are way too soft and deform easily for any number of reasons... I think they should be replaced any time they are exposed.
10-22-2017, 05:35 PM
#74
comment on lesson #1:
with the converter all the way in, measure how far past the bell-to-engine mating surface the converter bolt pad is.
comment on lesson #3:
I think teflon rings are way too soft and deform easily for any number of reasons... I think they should be replaced any time they are exposed.
with the converter all the way in, measure how far past the bell-to-engine mating surface the converter bolt pad is.
comment on lesson #3:
I think teflon rings are way too soft and deform easily for any number of reasons... I think they should be replaced any time they are exposed.
10-22-2017, 06:28 PM
#75
TECH Junkie
True story, to add a bit..... when seating the converter you will not always have three distinct clicks if ever. Measuring is by far the best bet when in doubt.
10-22-2017, 11:28 PM
#77
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Even if you have the converter all the way in, it can slide back from its own weight with a little mishandling of the transmission while under the vehicle. It's not a perfect world. Not in MY driveway, at least.
Mine bolted up surprisingly easily. Modern pump rotors are not like the old school pumps with steel gears. Not as forgiving.
I'm sharing this because there are so many open-ended threads about this shift problem. Most of them are on this site. Now there is ONE with a conclusion.
Sure, I made mistakes, but I am practically an authority on this transmission, now. It's no longer a mystery to me. I know what everything is, what it's called, and what it does. I see that as a good thing. I solved a problem that no one else on here could. I'm not a newb anymore.
Mine bolted up surprisingly easily. Modern pump rotors are not like the old school pumps with steel gears. Not as forgiving.
I'm sharing this because there are so many open-ended threads about this shift problem. Most of them are on this site. Now there is ONE with a conclusion.
Sure, I made mistakes, but I am practically an authority on this transmission, now. It's no longer a mystery to me. I know what everything is, what it's called, and what it does. I see that as a good thing. I solved a problem that no one else on here could. I'm not a newb anymore.
10-22-2017, 11:28 PM
#78
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10-23-2017, 03:16 AM
#79
TECH Senior Member
...
I'm sharing this because there are so many open-ended threads about this shift problem. Most of them are on this site. Now there is ONE with a conclusion.
Sure, I made mistakes, but I am practically an authority on this transmission, now. It's no longer a mystery to me. I know what everything is, what it's called, and what it does. I see that as a good thing. I solved a problem that no one else on here could. I'm not a newb anymore.
I'm sharing this because there are so many open-ended threads about this shift problem. Most of them are on this site. Now there is ONE with a conclusion.
Sure, I made mistakes, but I am practically an authority on this transmission, now. It's no longer a mystery to me. I know what everything is, what it's called, and what it does. I see that as a good thing. I solved a problem that no one else on here could. I'm not a newb anymore.
10-27-2017, 07:02 PM
#80
Moderator
Thanks for posting the update and solution which was basically "replace all wear parts".
As 98CayenneT/A stated, you cannot count on "3 clicks"; I've never even heard 3.
The only way to be sure is to measure to be sure the converter pads are a bit more than 1" recessed from the bell housing.
ALSO: When bolting up the transmission, only go finger tight (no wrench) before measuring for a gap between the flexplate and the converter. If there is not gap, the converter is not fully seated, but no damage has yet been done.
BTW - Sorry for not participating lately; I'm just getting back to ls1tech after taking the summer off for numerous track events (road course racing) and keeping 4 cars track-ready for myself, my wife and "24 Hours of Lemons" team racing.
As 98CayenneT/A stated, you cannot count on "3 clicks"; I've never even heard 3.
The only way to be sure is to measure to be sure the converter pads are a bit more than 1" recessed from the bell housing.
ALSO: When bolting up the transmission, only go finger tight (no wrench) before measuring for a gap between the flexplate and the converter. If there is not gap, the converter is not fully seated, but no damage has yet been done.
BTW - Sorry for not participating lately; I'm just getting back to ls1tech after taking the summer off for numerous track events (road course racing) and keeping 4 cars track-ready for myself, my wife and "24 Hours of Lemons" team racing.