Transfer case carnage

[BlakeB]

If memory serves me correctly, it was an older Durango.

I wonder if it’s like some of the Ram trucks, no disconnect between the front axle and transfer case so the front shaft is spinning anytime the vehicle is moving. If the u-joints get bad and start causing vibrations, the Tcase goes boom. Same principle applies to a bad driveshaft u-joint.
example: (not my pic) this was an 07 ram that had this happen to it.

 

[OVERKILL]

I wonder if it’s like some of the Ram trucks, no disconnect between the front axle and transfer case so the front shaft is spinning anytime the vehicle is moving. If the u-joints get bad and start causing vibrations, the Tcase goes boom. Same principle applies to a bad driveshaft u-joint.
example: (not my pic) this was an 07 ram that had this happen to it.
View attachment 25820

Fords were the same way, the hubs are fixed, so the front axle is always spinning the driveshaft. That's how our Expedition was and my buddy's far newer F-150, and yes, I expect the RAM's are the same way; probably most light duty trucks are.

The front u-joints did in fact go bad and nothing went boom on the Expedition FWIW.

 

[BlakeB]

Fords were the same way, the hubs are fixed, so the front axle is always spinning the driveshaft. That's how our Expedition was and my buddy's far newer F-150, and yes, I expect the RAM's are the same way; probably most light duty trucks are.

The front u-joints did in fact go bad and nothing went boom on the Expedition FWIW.

Ford uses IWE to lock and unlock the hubs. The front shaft can free spin but isn’t necessarily driven when everything is properly disengaged in 2wd.

2019 F-150 - 4WD - Revised IWE Operation Strategy After Initial ***SSM 48088*** - Ford F150 Forum - Community of Ford Truck Fans

2015 - 2020 Ford F150 - 2019 F-150 - 4WD - Revised IWE Operation Strategy After Initial ***SSM 48088*** - SSM 48088 - 2019 F-150/Expedition/Navigator - 4WD - Revised IWE Operation Strategy After Initial Start Up 2019 F-150/Expedition/Navigator vehicles equipped with four-wheel drive (4WD) have a...

www.f150forum.com

 

[OVERKILL]

Ford uses IWE to lock and unlock the hubs. The front shaft can free spin but isn’t necessarily driven when everything is properly disengaged in 2wd.

2019 F-150 - 4WD - Revised IWE Operation Strategy After Initial ***SSM 48088*** - Ford F150 Forum - Community of Ford Truck Fans

2015 - 2020 Ford F150 - 2019 F-150 - 4WD - Revised IWE Operation Strategy After Initial ***SSM 48088*** - SSM 48088 - 2019 F-150/Expedition/Navigator - 4WD - Revised IWE Operation Strategy After Initial Start Up 2019 F-150/Expedition/Navigator vehicles equipped with four-wheel drive (4WD) have a...

www.f150forum.com

Our Expedition, which just had an 8.8" in the front and disengagement happened in the T-Case, had no fancy vacuum control (IWE) I was under the impression that the F-150 with Auto 4x4 was similar or the same, but perhaps I'm wrong on that. On the Expy, the front shaft was always spinning.

 

[Jeff_S]

Fords were the same way, the hubs are fixed, so the front axle is always spinning the driveshaft. That's how our Expedition was and my buddy's far newer F-150, and yes, I expect the RAM's are the same way; probably most light duty trucks are.

The front u-joints did in fact go bad and nothing went boom on the Expedition FWIW.

IDK about the IFS Dodge/Rams, but the 2500+ Dodge trucks from '03-2013/14 had the front hub & driveshaft connected all the time. In '13/14 they changed back to using an axle disconnect on the front end, so the front driveshaft doesn't turn all the time now.

 

[Jeff_S]

Said driver left it it 4Low when driving on the freeway.

that was a different incident from a different poster. The OP said this pic was from an older durango.

 

[MNgopher]

Our Expedition, which just had an 8.8" in the front and disengagement happened in the T-Case, had no fancy vacuum control (IWE) I was under the impression that the F-150 with Auto 4x4 was similar or the same, but perhaps I'm wrong on that. On the Expy, the front shaft was always spinning.

With Auto 4x4 - yes, the driveshaft is always spinning. That is part of the on-demand transfer of power to the front if wheel slippage is detected.

Part time 4x4 - no. The IWE's provide the disconnect so the driveshaft does not have to spin. (that is part of testing if the IWE's are functioning - if the front driveshaft spins when it isn't supposed to )

 

[OVERKILL]

With Auto 4x4 - yes, the driveshaft is always spinning. That is part of the on-demand transfer of power to the front if wheel slippage is detected.

Part time 4x4 - no. The IWE's provide the disconnect so the driveshaft does not have to spin. (that is part of testing if the IWE's are functioning - if the front driveshaft spins when it isn't supposed to )

I guess we could muddy things with Part Time 4x4 systems that have the "Auto" option in the selector switch eh?

 

[Zaedock]

I believe that transfercase is upside down in the pic. Looks like chainstretch to me.
It happens, especially if the fluid is old/low.

I've rebuilt / slip yolk eliminated many New Process/Venture T-cases
I used to grenade regular NP231's in a similar fashion. You can still move in rear drive to get off the trail.
I picked up a JB Conversions NP231HD and have been running it for years. My new rig has a flipped Dana 300 cast iron case.

 

[The Critic]

Urgent blowout from the vehicle operator when it all went "bang".

 

[Gixxer8989]

I have also done a slip yoke eliminate on my jeep years ago. Then I bought and flipped and TWIN STICK Dana 300 for it.

 

[350Rocket]

On my 03 transfers case, there is an issue where you can get pump rub, and wear a small whole in the housing, causing fluid loss. I think np-246 cases are one of them. There are upgraded tabs to prevent this, if done before it wears through.
Could be what happened here.

My 05 Silverado has the same potential issue. I try to make it a habit to crawl underneath the transfer case and look for leaks frequently. So far so good. I also stopped using "auto" mode in the winter since it can apparently accelerate wear.

 

[1978elcamino]

Said driver left it it 4Low when driving on the freeway.

Yep, that will do it. An important lesson was learned here and I bet she will never do that again.