Lowering Transfer Case

Liro

Liro

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Apr 4, 2022
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Texas
I'm looking for temporary solutions to reducing vibrations of the 4" lift of my 1997 TJ. I believe it is a 4" rough country lift kit with probably 1" body lift and 3" suspension lift.

Would I be able to drop the transfer case more than an inch? I was imagining that the vibrations would reduce more than the 1" drop kit it currently has. I have dropped it to around 1.5" with a kit along with several washers to test and it went well but the vibrations stayed the same. I currently only have the drop kit's metal bars with no washers.

I have a tom woods oem-style front driveshaft and the stock rear, no SYE, and using stock/unadjustable control arms. I currently daily with the front driveshaft out and it runs smooth but I do want to use 4x4 without having to install it every time.

Let me know if you need more info,
Thank you in advance
 
Just to clarify, are the vibes present after removing the front driveshaft? Do you feel the vibes in the steering wheel or the floorboards?
 
Normally you get vibes on the the rear driveshaft, not the front. Sounds like your pinion angle/caster angle is off or possibly bad driveshaft joints.
 
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The transfer case drop I removed from my Jeep was nothing more than a couple of feet of .188 wall square tube with three holes drilled in it.

You can buy a 20' stick at a metal yard for $30 or they'd probably sell you 6'. Drill some holes, buy some longer bolts and try it.

You're only out a little cash and some labor.

My Jeep was all over the place when I bought it. I put a SYE and new Adams driveshafts in...that a bunch of other stuff and it's quiet(er), straight and no more white knuckle driving...lot of good information on these forums.

-Mac
 
If your front driveshaft is older and has not been rebuilt you may really need to look into that- You do not want those to fail- It can nearly total a TJ.

You also may need to have it re-balanced- And make sure it is seated properly in the yokes-

@Shawn at Tom Wood's will see this and maybe he can chime in- His family has been giving people the shaft for years. Well actually they sold it to them....
 
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Dont know if this applies to front drive line but when I installed sye and new Tom Woods drive shaft I still had vibes. Drove me crazy till I did research and found that the driveline could be 180 out. Turned 1/2 turn and vibes gone. Might try front. Food for thought, Good luck. Hate vibes.
 
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So, is there any level of vibration that is acceptable?

I just had a Dana 44 swapped in for my Dana 35. The Dana 35 had some significant vibrations from 0 - 4 mph and then was smooth. The Dana 44 has no vibrations from 0, but might have some slight vibrations around 20mph/2K rpm. It's difficult to detect them on these shitty roads so I'm wondering if this slight level of vibration is acceptable. If not, I'm prepared to go to a SYE & DC rear driveshaft & and adjustable control arms. But if I can avoid that, I certainly would.

I also have a 1" transfer case drop ready to install. (Once those damn bolts are soaked enough to release.) Should I just try the TC drop first?

Sorry if I'm high jacking this thread. I'm having a difficult time asking questions by starting a new thread because it seems these questions get asked all the freaking time.

Thanks.

Edit: Just saw this from Jerry B.: "There is no amount of drivetrain vibration that is acceptable or can just be lived with. A drivetrain vibration will, sooner or later depending on how bad it is, take out bearings, u-joints, and/or seals."
 
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HaydukeLives! said:
I also have a 1" transfer case drop ready to install. (Once those damn bolts are soaked enough to release.) Should I just try the TC drop first?
Click to expand...
Sure, try the TC drop. Or remove one driveshaft at a time and drive it.

I found the best way to identify a barely-felt vibration, when you're not sure if it's really there, is to remove a driveshaft. If it suddenly runs glass-smooth, it was real and you've found it.
 
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HaydukeLives! said:
So, is there any level of vibration that is acceptable?

Edit: Just saw this from Jerry B.: "There is no amount of drivetrain vibration that is acceptable or can just be lived with. A drivetrain vibration will, sooner or later depending on how bad it is, take out bearings, u-joints, and/or seals."
Click to expand...
Glad you found that. :)
 
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Harlyman said:
Dont know if this applies to front drive line but when I installed sye and new Tom Woods drive shaft I still had vibes. Drove me crazy till I did research and found that the driveline could be 180 out. Turned 1/2 turn and vibes gone. Might try front. Food for thought, Good luck. Hate vibes.
Click to expand...

That's interesting.
I thought out of phase vibes were only an issue if the driveshaft had been pulled apart and reassembled 180° off.
 
LONGJP2 said:
That's interesting.
I thought out of phase vibes were only an issue if the driveshaft had been pulled apart and reassembled 180° off.
Click to expand...
Out of phase vibrations yes but not from vibrations from the rear driveshaft u-joints being forced into excessive operating angles as happens after installing suspension lifts.
 
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Jerry Bransford said:
Out of phase vibrations yes but not from vibrations from the rear driveshaft u-joints being forced into excessive operating angles as happens after installing suspension lifts.
Click to expand...

Ok, but that doesn't explain this.

Harlyman said:
Dont know if this applies to front drive line but when I installed sye and new Tom Woods drive shaft I still had vibes. Drove me crazy till I did research and found that the driveline could be 180 out. Turned 1/2 turn and vibes gone. Might try front. Food for thought, Good luck. Hate vibes.
Click to expand...
I doubt his new TW driveshaft was balanced and then reassembled 180° out.
 
Jerry Bransford said:
Easy, bad pinion angle.
Click to expand...

Ok, but that doesn't explain this either.

Harlyman said:
Dont know if this applies to front drive line but when I installed sye and new Tom Woods drive shaft I still had vibes. Drove me crazy till I did research and found that the driveline could be 180 out. Turned 1/2 turn and vibes gone. Might try front. Food for thought, Good luck. Hate vibes.
Click to expand...
 
I have read that when I installed a sye and a new TW drive shaft that it could be 180 out. I only have a 2.75 inch lift fully adjustable upper and lower MC control arms. I turned drive shaft on sye end 180 and cured those vibration. The drive line is brand new and balanced. Great drive lie from Tom Woods.
 
Anyway going back my original post.
It’s a new tom woods driveshaft, i’ve removed and installed it several times probably both orientations but since everything is stock, i don’t think it’ll help switching. I can’t adjust pinion angles i’m a broke college student to buy upper arms rn. All I needed was to see if I could drop the trans a bit more with more spacers to revert the trans to a more stock level but i’ll try later. This vibe shakes my mirrors with the front installed.

Btw preaching to the choir here about bad ujoints, still dealing with a crack in my tcase from the front shaft blowing up while ago. Just needed confirmation on dropping trans some more at the current lift
 
Anyway going back my original post.
It’s a new tom woods driveshaft, i’ve removed and installed it several times probably both orientations but since everything is stock, i don’t think it’ll help switching. I can’t adjust pinion angles i’m a broke college student to buy upper arms rn. All I needed was to see if I could drop the trans a bit more with more spacers to revert the trans to a more stock level but i’ll try later. This vibe shakes my mirrors with the front installed.

Btw preaching to the choir here about bad ujoints, still dealing with a crack in my tcase from the front shaft blowing up while ago. Just needed confirmation on dropping trans some more at the current lift
 
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