Transfer case clocking in reverse (1 Viewer)

[Maynster]

Did some searching and couldn’t find anything that quite seemed to match up. I’ve read the TSB’s for the tranny, and I’ve already got a performance valve body in it. Under hard reverse the transfer case moves counter clockwise and a load noise ensued. It’s not slipping in reverse that I can tell, but it sounds like the transfer case is running up and down a threaded rod?
Any insight would be appreciated

 

[jonheld]

I'm confused regarding the statement, "the transfer case moves"
What exactly is moving? The transfer case is bolted to the transmission housing with 6 17mm bolts. It is not possible for it to move independently unless the case is cracked.

 

[Maynster]

Sorry. Clarifying. The whole assembly is likely rotating counter clockwise, but what I can see, the transfer case hi low shifter, and hear the transfer case is the most direct indicators. I’ll try to take video of it after work. Hopefully without running over my cell phone….
I can replicate it by throttling up in the reverse gear while standing on the brakes.
Thanks

 

[Shipwreck]

Your engine mounts and/or transmission mounts are cracked.

 

[Mark W]

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[Maynster]

I’ll give that a look. The motor has enough low end torque I suppose. I didn’t really consider it as they’re about 5 years old, and OEM.

 

[jonheld]

Sorry. Clarifying. The whole assembly is likely rotating counter clockwise, but what I can see, the transfer case hi low shifter, and hear the transfer case is the most direct indicators. I’ll try to take video of it after work. Hopefully without running over my cell phone….
I can replicate it by throttling up in the reverse gear while standing on the brakes.
Thanks

The transfer case shifter is bolted to the top of the transmission housing. When power braking in either forward or reverse, you will always have some movement, as the engine/transmission/transfer case is on semi-flexible mounts.
The A343F is also known to occasionally have a "squealing" sound in reverse when under load in high range.

 

[Maynster]

Unfortunately not a squeal sound. More like a singular crunch, or a heavy object sliding on a piece of all thread. I’ll try and get a vid after work in a couple of hours.

 

[60wag]

Is your engine fan hitting the radiator shroud?

 

[Maynster]

No. Definitely not. The crunch sound is coming from under the rig. No witness marks on the fan or shroud. Normal easy backing doesn’t cause it. Only under load or giving the skinny pedal a good stab in reverse typically in high traction.

 

[Maynster]

Okay. Sounds more dramatic backing under load than standing on the brake to produce load. So I’m retrospect it is more of a squeak.
A couple video attempts. Last one Slow motion





Slow motion - https://youtube.com/shorts/953iuhgLylw?feature=share

 

[lelandEOD]

Bizarre. U-joint possibly?

 

[Maynster]

I don’t think so. I’m hoping is that transfer case pad and rod on the passenger side of the case. The one that has a 4” (poorly calibrated eye) gap and a big old bolt with a pad on top? If not, it may be the transmission. I do know that I’ve a heavy duty valve body in the trans that I bought from djsixbillion Desmond, as I’ve his motor from the rig that was totaled.

 

[jonheld]

I don’t think so. I’m hoping is that transfer case pad and rod on the passenger side of the case. The one that has a 4” (poorly calibrated eye) gap and a big old bolt with a pad on top? If not, it may be the transmission. I do know that I’ve a heavy duty valve body in the trans that I bought from djsixbillion Desmond, as I’ve his motor from the rig that was totaled.

That large cube shaped "pad" on the right side of the transfer case is a counterbalance to suppress vibration. It is easily removable with 2 bolts and, quite frankly, I have found that it makes no difference if it is installed or not. In any case, it does not contact anything; or I should say, it's not supposed to be in contact with anything. It just hangs on the side of the transfer case.

 

[Shipwreck]

Drain the oil from your transfer case and check for metal shavings. If it is clear, I would then check diffs and possibly tranny. From your video, it looks like the drive train loads up then jumps back to unload. It looks like it skips a couple teeth on the gears. Does it do this with the center diff locked?
I would remove the drive shafts and check for play in the flanges of the transfer and the differentials.

 

[Maynster]

I’ll give the center diff lock a try after work. I’ve a front pinion growl, but I’ve had no issues going forward. Will have to look into the fluids.

 

[Maynster]

Well. I’m tentatively thinking it’s the viscus coupler. Turned the center diff lock on and no issue. Gonna go to a dirt patch here after work and give it the business. If it is the VC, I’ll go to a part time kit. I e been kicking around that idea for awhile. The transfer case itself has nearly 380k on it. I’ve a spare on the garage floor. I’ll post up after I flog it some after work.

 

[Maynster]

Yeah… a lot harder to make it happen, but I got the same result. It happens just as I let off the throttle. Low range doesn’t happen. I checked the mounts and they are good to go. No cracks it the mounts.

 

[Maynster]

Diving deeper into the rabbit hole, and after the experiments, I’ve pretty much settled on it’s the typical tranny noise the A343f makes in revers. The issue that uncle T tried to keep fixing past the 80 series end dates here in the US.

 

[gummycarbs]

Does it happen with the transfer case locked?