241C Transfer Case Vibration WEIRD???

[Midnight]

with A/C on? maybe that load causes a more pronounced engine vibration that is transferring, like Schurkey was saying. How do the engine and tranny mounts look?

Yeah I've definitely been trying to figure this out. Everything seems to look alright visually anyway. I took a picture of my setup to show because I was a little confused... Transfer case mounted where the transmission should be mounted???

 

[funnyfarm]

1992 GMC K1500. 700r4. 6in Suspension Lift. I'm getting a vibration in my transfer case ONLY with the A/C switched on and even if I have the transfer case in neutral. Everything else seems to be working just fine. Mechanic thinks its probably the dreaded "pump rub". I guess my question at the moment is - Would I get the rub even with the case in neutral? Hopefully you all will have some comments/suggestions on anything else that might make sense to me. Thanks!

I would almost wonder if he might have a bad transmission mount or motor mount I know when the AC is on it puts a big load on the engine and with its cycling on and off on the clutch of the AC pump I would think that would have to be a mount problem unless you have a pulley up front that is crooked or going out and centrifugal force is causing the vibration

 

[scott2093]

Transfer case mounted where the transmission should be mounted???

technically that extension housing is part of the transmission

 

[Midnight]

technically that extension housing is part of the transmission

Thanks for the reply and I guess I get that...

But wouldn't I also want some stabilization there? I'm currently on the hunt for a prefab crossmember that would support both the transmission and the transfer case...

Anyone know of something like this on the market?

 

[Midnight]

I would almost wonder if he might have a bad transmission mount or motor mount I know when the AC is on it puts a big load on the engine and with its cycling on and off on the clutch of the AC pump I would think that would have to be a mount problem unless you have a pulley up front that is crooked or going out and centrifugal force is causing the vibration

It doesn't seem to be effected by any "cycling".

 

[1Ton_s-blazer]

Does your drivers drop case have the 2 big bolt holes for the brace to the bellhousing like the square bodies? It's a quick try compared to a crossmember.

 

[Midnight]

"Pump rub" is new to me. Never heard of it before. I can't comment on "pump rub" beyond that.

The entire output side of the gear train would be stationary, the driveshafts/U-joints would be stationary, the differentials would be stationary. I suppose the input side of the transfer case could be rotating. So a problem on the input side--failing bearing or thrust washer, for example--might be noisy.

I think you're mis-diagnosing a vibration from something else--an exhaust heat shield, the flexplate, the serpentine belt/tensioner...and getting caught-up in "transfer case" when the problem is somewhere else.

But I've been wrong before, and I'm not there to inspect it.

I'm actually beginning to think that it's the stall converter that was put in this thing: GM18AH. Any thoughts?

 

[Midnight]

with A/C on? maybe that load causes a more pronounced engine vibration that is transferring, like Schurkey was saying. How do the engine and tranny mounts look?

I'm actually beginning to think that it's the stall converter that was put in this thing: GM18AH. Any thoughts?

 

[Midnight]

Does your drivers drop case have the 2 big bolt holes for the brace to the bellhousing like the square bodies? It's a quick try compared to a crossmember.

I actually have that brace for both sides (which I picked up after buying the truck) but they're disconnected because the truck is also missing the brackets on the motor mounts that they would mount to.

 

[1Ton_s-blazer]

I was talking about the brace between the t-case and engine, holes on t-case might be a passenger drop only deal. You're talking about the cover and engine braces. What do you think of this color "misty grey" ?

What's your rpm Ac on vs off?
Does it change in any range P-R-N-4-...?
Why are you thinking converter?
How long has it been in the truck?
What stall?
Does it have a brazed impeller and/or turbine?