Pops into neutral

[Cummins12V98]

My Cousin has I believe a 06 with 6 speed stick and manual transfer case. When coasting down a long grade in 6th his transfer case pops into neutral. This just started happening and has repeated doing so several times. Thoughts???

 

[Ozymandias]

Worn out - under load, in any direction these dog clutches can not slip out.
Hard to explain for me.. but I try it anyways...
The way they are designed, made, is that the teeth have a slight angle to the "rear". So if there is a load on them the gear is actually pulled more and harder into engagement. Cruise or coast doesn't matter for this effect. If yours pop out more then likely they are worn down level, can't hold the engagement anymore.
Every manual transmission is built that way, that's why you can't pull a gear out with the lever as long as there is a load on the transmission.

 

[Rowdy Dalton]

Worn out - under load, in any direction these dog clutches can not slip out.
Hard to explain for me.. but I try it anyways...
The way they are designed, made, is that the teeth have a slight angle to the "rear". So if there is a load on them the gear is actually pulled more and harder into engagement. Cruise or coast doesn't matter for this effect. If yours pop out more then likely they are worn down level, can't hold the engagement anymore.
Every manual transmission is built that way, that's why you can't pull a gear out with the lever as long as there is a load on the transmission.

In other words, its time to get the transmission rebuilt.

.

 

[Cummins12V98]

What I stated originally is correct. Just talked to Cousin. He said coasting down a long grade in 6th the transfer case shifter literally pops from 2H to Neutral. Transmission does NOT pop out of gear. His truck is a 05 6 speed without an exhaust brake.

At the end of the grade when he wants to start accelerating engine revs, he looks down and transfer case shifter has moved to neutral. Pops it back in 2H and off he goes.

 

[AH64ID]

Have him check for loose linkage.

 

[CVR222NV]

My research on manual transfer cases reveals that the linkage is the weak link. My recollection is that Dodge upgraded the linkage so he might want to consider replacing with upgraded OEM if it is more than just needing adjusting. The best modification I have seen is to replace the OEM linkage with heim joints and a solid steel rod:

https://www.cumminsforum.com/threads/transfer-case-linkage.1667434/

The measurements from this CF thread is for a 2007.5 3500 so may be different than his 2006 but it looks like McMaster-Carr has different sizes rods so he should be able to get a custom fit. The only negative I have heard about this modification is that you have to keep the heim joints lubed to keep vibrations coming into the cab through the shifter.

 

[Cummins12V98]

More info, sounds like his friend that is a Mechanic placed the tuck on his lift and removed the linkage and everything felt tight moving the selector. He did not look at the bushings so that will be his next thing to to when he gets back home.

Thanks for all the help!!!