Attn Vince@FLT: 4L80E Gear bind? open to all theories!
12-22-2008, 10:17 PM
#11
I'm not sure what you are talking about when you say bushings in the direct drum. There are not any bushings in the direct drum. The sun gear shaft has bushings that wear bad and also the center support. Both of which when worn will cause the direct drum to come into contact with the center support. Being that you had issues with the ring lands on the center support, the direct drum has to be damaged. Think about it what caused the burs? Vince
10-05-2010, 01:36 PM
#14
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Hi fellas this thread had a wealth of good information for an issue that I'm having which has most all of the same symptoms gman had.
This is my second time installing this transmission. Both times with the same symptoms... 2nd gear start and a bind when hitting third gear. I am not able to tell if I have binding in reverse because the brakes on this thing are pretty rusty so they are providing some resitance when accelerating.
The first time it was installed I ended up burning up the intermediate clutches and upon dissasembly I found my center support piston stuck in the engaged position. I figured this happened from max line pressure since I had an issue with my VSS initially. The piston was so far extended on the center support that the lip seal had partially come out of the bore causing the frozen piston. I replaced the center support as well as the piston and return springs because I attributed the problem to a worn return spring on the old center support.
once I reassemble the transmission and air tested the center support a dozen times I reinstalled the tranny and.. voila.. same issue. I started up the road but right away knew i had started in 2nd gear because it felt like I had a high stall converter. However, my GMTD scan tech said I was in 1st shifting into second when the binding occured so what I thought I felt and what the ecm was saying were two different things.
I am now thoroughly stumped... I removed the valve body to make sure the transgo plate had all the appropriate holes, they were the right size, and that I had the correct VB gaskets. Everything checked out to a tee... as well as the check ball location. I really could use some advice from the Gman or Vince on this matter. This issue has been causing me to lose sleep since May!!! LOL and everyday I get depressed when I pull in andd see the truck sitting there immobilized. This is not a main source of transportation and I have a significant amount of cash and pride tied up in this rebuild with all of the finest internals so I didn't want to break down and buy a used tranny just to get me around until I get this figured out. HELP PLEASE
@Vince- In everything I found, read...tech's I've spoken to and product support specialists contacted you are hands down the most knowledgable, friendly, and helpful builder I've ever come across. I see your name and good advice on MANY forums and I'm already appreciative on many tips I gained from your posts... Thank you!
This is my second time installing this transmission. Both times with the same symptoms... 2nd gear start and a bind when hitting third gear. I am not able to tell if I have binding in reverse because the brakes on this thing are pretty rusty so they are providing some resitance when accelerating.
The first time it was installed I ended up burning up the intermediate clutches and upon dissasembly I found my center support piston stuck in the engaged position. I figured this happened from max line pressure since I had an issue with my VSS initially. The piston was so far extended on the center support that the lip seal had partially come out of the bore causing the frozen piston. I replaced the center support as well as the piston and return springs because I attributed the problem to a worn return spring on the old center support.
once I reassemble the transmission and air tested the center support a dozen times I reinstalled the tranny and.. voila.. same issue. I started up the road but right away knew i had started in 2nd gear because it felt like I had a high stall converter. However, my GMTD scan tech said I was in 1st shifting into second when the binding occured so what I thought I felt and what the ecm was saying were two different things.
I am now thoroughly stumped... I removed the valve body to make sure the transgo plate had all the appropriate holes, they were the right size, and that I had the correct VB gaskets. Everything checked out to a tee... as well as the check ball location. I really could use some advice from the Gman or Vince on this matter. This issue has been causing me to lose sleep since May!!! LOL and everyday I get depressed when I pull in andd see the truck sitting there immobilized. This is not a main source of transportation and I have a significant amount of cash and pride tied up in this rebuild with all of the finest internals so I didn't want to break down and buy a used tranny just to get me around until I get this figured out. HELP PLEASE
@Vince- In everything I found, read...tech's I've spoken to and product support specialists contacted you are hands down the most knowledgable, friendly, and helpful builder I've ever come across. I see your name and good advice on MANY forums and I'm already appreciative on many tips I gained from your posts... Thank you!
10-05-2010, 05:17 PM
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Additional details:
The only modification to the valve body was a replacement accumulator valve spring provided in my TCI kit that was part of their "Trans-Scat" shift kit. I completely dissasembled the valve body, cleaned it under surgical conditions and reassembled after I had this issue the first time around so I am confident that everything is tight there.
I air tested the center support on the bench as well as while it was in the case during both rebuilds. This is a new center support now and a different set of frictions and steels in the intermediate clutch. I have a 1995 model so it is the older style front oiler case. I also air tested when it was bolted to the case, upon installing the intermediate clutches, and again before the VB went on. I also air tested it once again today when I had the valve body off and the center support is moving freely (thank god since I already had one freeze up).
I also hooked up my GMTD scan tech to verify that it was in fact binding in 3rd gear. So as far as I can tell, 3rd and 4th gear act like a trans brake. With the vehicle in jackstands and manually selecting 3rd or 4th gear with the Scan Tech the wheels will not spin at all. There is some hardcore issues occuring and I'm beginning to lean towards a possible ECM error... but I don't know for sure. I replaced the transgo seperator plate with the original plate to see if that made a difference but it did not. Interestingly enough, the transgo plate 48-PLT-01 is identical to the one shown in the back of the ATSG rebuild manual in the section that shows the updated parts through the years. The two holes shown in that figure that are related to overseas models are flip flopped between the original seperator plate and the transgo.
The only modification to the valve body was a replacement accumulator valve spring provided in my TCI kit that was part of their "Trans-Scat" shift kit. I completely dissasembled the valve body, cleaned it under surgical conditions and reassembled after I had this issue the first time around so I am confident that everything is tight there.
I air tested the center support on the bench as well as while it was in the case during both rebuilds. This is a new center support now and a different set of frictions and steels in the intermediate clutch. I have a 1995 model so it is the older style front oiler case. I also air tested when it was bolted to the case, upon installing the intermediate clutches, and again before the VB went on. I also air tested it once again today when I had the valve body off and the center support is moving freely (thank god since I already had one freeze up).
I also hooked up my GMTD scan tech to verify that it was in fact binding in 3rd gear. So as far as I can tell, 3rd and 4th gear act like a trans brake. With the vehicle in jackstands and manually selecting 3rd or 4th gear with the Scan Tech the wheels will not spin at all. There is some hardcore issues occuring and I'm beginning to lean towards a possible ECM error... but I don't know for sure. I replaced the transgo seperator plate with the original plate to see if that made a difference but it did not. Interestingly enough, the transgo plate 48-PLT-01 is identical to the one shown in the back of the ATSG rebuild manual in the section that shows the updated parts through the years. The two holes shown in that figure that are related to overseas models are flip flopped between the original seperator plate and the transgo.
10-05-2010, 07:11 PM
#17
Gman what fixed your transmission in the end? It's always nice to hear how things turned out in the end after donating my time!
Primo thanks for the kind words. I do try to help when I have time. On the issue with the intermediate piston being stuck outside of its bore. In my opinion this was caused because the clutches were shot and caused additional clearance. Basically the piston had more room to travel than it was designed for! The spring cage will bend over extended use and especially when a clutch pack is completely worn out. I think something else caused the clutch pack to fail and what you saw was just the carnage from it!
Most of the info for what you need to do and also look for I believe was covered in this thread. In most cases the issue is something that was missed on the rebuild or something that should have been checked and was over looked. Or the obvious the re-builder caused the issue. I see this often when taking units apart that someone had just tried to overhaul however they failed.
One issue that I recently saw was when using a late design over drive roller clutch. I can not remember what symptom it caused however if you are not careful when installing it, the clutch will free wheel in both directions. Might be something to check. A miss installed one way roller clutch or sprag can cause an instant failure in a transmission. Best of luck getting this thing straightened out. Please let us know what you come up with. Vince
Primo thanks for the kind words. I do try to help when I have time. On the issue with the intermediate piston being stuck outside of its bore. In my opinion this was caused because the clutches were shot and caused additional clearance. Basically the piston had more room to travel than it was designed for! The spring cage will bend over extended use and especially when a clutch pack is completely worn out. I think something else caused the clutch pack to fail and what you saw was just the carnage from it!
Most of the info for what you need to do and also look for I believe was covered in this thread. In most cases the issue is something that was missed on the rebuild or something that should have been checked and was over looked. Or the obvious the re-builder caused the issue. I see this often when taking units apart that someone had just tried to overhaul however they failed.
One issue that I recently saw was when using a late design over drive roller clutch. I can not remember what symptom it caused however if you are not careful when installing it, the clutch will free wheel in both directions. Might be something to check. A miss installed one way roller clutch or sprag can cause an instant failure in a transmission. Best of luck getting this thing straightened out. Please let us know what you come up with. Vince
10-06-2010, 09:40 AM
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Vince, What turned out to be my problem was a mis-installed transgo HD2 kit. To start, the actuator feed screen was giving me problems. (I had a thread about it on here too). Turns out I had the nipple on the round block off plug that goes in behind it facing the wrong direction. Also, somehow, Instead of using the transgo gaskets, I used the stock VB to plate and plate to case gaskets. Dropped all that down and she's a hoss now! Just glad it wasn't an internal problem, which I thought it was!
10-06-2010, 07:16 PM
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I pulled the valve body to make sure there were no issues with blocked passages or checkballs...things of that nature. I also put the factory seperator plate back in but no changes.
I picked up a used transmission to get me through the winter and I'm going to send this one to a rebuilder to go through it and tell me what I did wrong. Once that's figured out I'll post an update.
I picked up a used transmission to get me through the winter and I'm going to send this one to a rebuilder to go through it and tell me what I did wrong. Once that's figured out I'll post an update.
10-06-2010, 07:30 PM
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Sorry to hear that man! I know you've got a lot tied up in it; money, time, blood, sweat and undoubtedly probably some tears. I know you'll be glad to get her goin though eventually.
Vince: Could it have been a stuck solenoid, or a gimp EPC module? One thing I just thought of, assuming what Im saying is correct, is one main wiring difference between 4l60's and 4l80s is that 4l60 solenoids are always on and shut off to shift; 80e's turn on to shift. Could be as simple as a broken harness in this case, correct? This is just going off memory, so I'm not sure if what im saying is correct; just thinking out loud.
Vince: Could it have been a stuck solenoid, or a gimp EPC module? One thing I just thought of, assuming what Im saying is correct, is one main wiring difference between 4l60's and 4l80s is that 4l60 solenoids are always on and shut off to shift; 80e's turn on to shift. Could be as simple as a broken harness in this case, correct? This is just going off memory, so I'm not sure if what im saying is correct; just thinking out loud.
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