06 lbz with transmission issues

cjbennett1984

Member
Sep 3, 2021
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After about an hour on the hwy on deceleration a very strange noise filled the cab for about a second and a half. Sounded like a canvas zipper the rims picked up then the truck goes back into normal mode. Moderate acceleration seems normal without slipping. But as soon as you let off on the accelerator the zipper sound fills the cab and the rims go up for a brief moment then back to normal. This all started around 20 miles from the house and toward the end of our trip became more frequent. Dropped the transmission into manual and limited it to 5th gear. Eventually it would do that as well in 5th gear. Still checking this seems to only happen deceleration. No leaks, the fluid level is good the fluid is red in color (dark) doesn't seem to smell smoky or burnt. Any advice would be greatly appreciated
 

cjbennett1984

Member
Sep 3, 2021
39
1
8
After about an hour on the hwy on deceleration a very strange noise filled the cab for about a second and a half. Sounded like a canvas zipper the rims picked up then the truck goes back into normal mode. Moderate acceleration seems normal without slipping. But as soon as you let off on the accelerator the zipper sound fills the cab and the rims go up for a brief moment then back to normal. This all started around 20 miles from the house and toward the end of our trip became more frequent. Dropped the transmission into manual and limited it to 5th gear. Eventually it would do that as well in 5th gear. Still checking this seems to only happen deceleration. No leaks, the fluid level is good the fluid is red in color (dark) doesn't seem to smell smoky or burnt. Any advice would be greatly appreciated.
Little back ground on the truck, 06 lbz, 245k miles. Just replaced the injectors, engine harness, had the ecm checked, and repaired a grounded injector wire. Have had a ppe tune in the truck for about 10 years. The cat has been removed. Bought the truck with a 6" lift and 35" tires 4x4.
 

TheBac

Why do I keep doing this?
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Apr 19, 2008
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Merged your threads and moved the result to Trans Talk.

Wish you new guys would go out and buy a good code reader so you can get the codes before you post the problem so more information is available.
Stop making the guys guess so much. Its not productive time.
 

2004LB7

Well-known member
Dec 15, 2010
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don't forget to inspect the drive shaft u joints and fluid in the transfer case and diff.
 

cjbennett1984

Member
Sep 3, 2021
39
1
8
Sorry if I am waisting everyone's time. I attempted to provide as much information as I could. I have never experienced anything like this before which makes it difficult to describe.
My tuner has a diagnostic tool and while something drastic seems to be happening, intermittently, there are no codes shown or indicated on the dash. So I assume there aren't any codes. The universal joints have been recently replaced. A previous mystery that has been solved. The lip seal on the transfer case was replaced about a year ago. It has not shown any signs of leakage since.
 

2004LB7

Well-known member
Dec 15, 2010
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did you actually inspect or just look and think because you see no leaks or because the joints where recently replaced they are still fine? you need to remember that we can't see or touch the truck from the other end of the internet. you need to do the leg work and give us as mush as possible. many scanners will not read transmission codes. verify if yours can or get one that does. if you are at a loss or don't know what to do I suggest you take it to a shop and have them look it over

maybe put a camera underneath and drive it to create the noise and see if you can pin point the location of the noise
 
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cjbennett1984

Member
Sep 3, 2021
39
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After we installed the new injectors and wiring harness and were still experiencing the shorting through the nicked injector wiring. The transmission was shifting very hard at times. Strangely, so hard that it felt like something could get broke. But after we found the shorting injector wore it never behaved like that again. Never thought about it since until you mentioned the transfer case fork. Does that require a new transfer case or is it rebuildable? My brother in law had to replace his as the lip seal got damaged and ruined the opening preventing a seal replacement? Thanks for the suggestions I will look into it further and climb underneath tonight to check the u joints and seals. I will also run diagnostics with my tuner to see if anything shows up
 

cjbennett1984

Member
Sep 3, 2021
39
1
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Saw this video last nite and it sounded pretty much the same. It seems to make sense as well. Not to mention the way the tyranny was banging into gear that I previously mentioned when we were having wiring issues with the injectors. Seems like a good place to start. I may end up yanking the whole tc out anyway but this looks easy enough to start with.

Source: https://youtu.be/MKSHtje5_uo
 

Bdsankey

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Feb 1, 2018
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Saw this video last nite and it sounded pretty much the same. It seems to make sense as well. Not to mention the way the tyranny was banging into gear that I previously mentioned when we were having wiring issues with the injectors. Seems like a good place to start. I may end up yanking the whole tc out anyway but this looks easy enough to start with.

Source: https://youtu.be/MKSHtje5_uo

The transfer cases in our trucks do not tear down while in the truck easily like the video you posted, you will have to remove it to remove the rear housing. Removing the transfer case is all of ~30min.
 

cjbennett1984

Member
Sep 3, 2021
39
1
8
Pulled the TC over the weekend. Bought two different sets of snap ring pliers and was still. Unable to get the first snap ring off so I can pull the case apart. I ended up making another run for some snap ring pliers that are specifically designed for the outside ring. It still feel like they don't open up enough and after trying to get the case apart for over two hours I ran out of time. I can spread the clip but can't seem to get it completely out of the groove so that the saft will allow the. Ase to spread. I did see pieces in the drain plug while draining it. Watched quite a few people effortlessly remove this ring and continue to split the case. I did notice the snap ring does allow the shaft to slide toward the front and back about a quarter of an inch. I think that is why the gears are slipping. But until I get the case apart I won't know.
 

cjbennett1984

Member
Sep 3, 2021
39
1
8
After much you tube education and research I decided that rebuilding the existing transfer case might not be my best option. I don't want to experience another failure pulling our camper down the road just to end up spending time in a shop. Found kodiac trucks with an improved design for the transfer cases. They have identified some of the known weak links and resolved them. Adding roller bearing on the main Shaft. Which appears to improve the design. I ordered one and installed it over the weekend. They recomend 5w-20 full synthetic for the lubricant. The horrible zipper noise is gone. An the truck seems to be back in great shape. Thanks for the recomendations and support. Another note. The guy at kodiac indicated these transfer cases normally fial between 125k-175k. So at 245k I guess I got my money's worth.