97 TJ transfer case drop (need confirmation)

[mtnjam20]

Thank you in advance! Long time XJ/ZJ owner and currently working on a 97 TJ for my 17 y.o. son. Getting drive line vibrations 30-35 mph. Unsure about exact suspension lift but seems to be 3-4" (running 33s). No SYE kit/upgraded shafts are installed. Was planning to put a 0.5-1" TC drop kit (or washers/new bolts) in but concerned with what I'm seeing.

(a) can someone confirm this 1.5" STEEL BAR in pic is a homemade TC drop (or maybe some aftermarket kit I can't verify)? 99.9% sure but better to ask
(b) at approx 3-4" lift is 1.5" too much drop? and can this be causing vibrations and basically same as what you'd see with NO drop kit?
(c) vibration is felt primarily at front end/steering wheel but some mid to rear vibration is there...I understand how that can be exaggerated throughout
(d) understand a SYE kit is best solution overall but trying to work within budget and also now worried about best way to proceed given what I'm seeing installed and symptoms.

Again, thank you, these forums are so important in my opinion!

 

[Chris]

(a) can someone confirm this 1.5" STEEL BAR in pic is a homemade TC drop (or maybe some aftermarket kit I can't verify)? 99.9% sure but better to ask
(b) at approx 3-4" lift is 1.5" too much drop? and can this be causing vibrations and basically same as what you'd see with NO drop kit?
(c) vibration is felt primarily at front end/steering wheel but some mid to rear vibration is there...I understand how that can be exaggerated throughout
(d) understand a SYE kit is best solution overall but trying to work within budget and also now worried about best way to proceed given what I'm seeing installed and symptoms.

Again, thank you, these forums are so important in my opinion!

a) Yes, that's a homemade TC drop
b) Drop varies from vehicle-to-vehicle and no two vehicles will be the same even with the same lift installed. For 4" of lift that is probably about right.
c) The vibration could be many things
d) Have a competent shop balance your wheels. Your culprit might have nothing at all to do with the driveline.

Does the lift have adjustable control arms?

 

[mtnjam20]

Thank you Chris! Control arms are not adjustable. Fairly new to our FL area, but alignment and balance was done at a shop trusted by a lot of Jeep owners here. Their suggestion was a SYE kit but I have not been back to discuss this 1.5" TC drop (and honestly I didn't notice it prior-to).

 

[mtnjam20]

Thank you Chris! Control arms are not adjustable. Fairly new to our FL area, but alignment and balance was done at a shop trusted by a lot of Jeep owners here. Their suggestion was a SYE kit but I have not been back to discuss this 1.5" TC drop (and honestly I didn't notice it prior-to).

Lift confirmed to be 4" (front springs 16" rear springs 12"). Motor mounts and u joints look good, bushings good and again control arms are fixed and alignment/balance just done. Anyone advise if adding washers to the existing 1.5" drop OR reducing drop may help or should I look elsewhere since the 1.5" drop-bar is there?

 

[lBasket]

Lift confirmed to be 4" (front springs 16" rear springs 12"). Motor mounts and u joints look good, bushings good and again control arms are fixed and alignment/balance just done. Anyone advise if adding washers to the existing 1.5" drop OR reducing drop may help or should I look elsewhere since the 1.5" drop-bar is there?
View attachment 585824

I mean, no matter what way you slice it, the tcase drop is a hacky bandaid and the SYE and/or adjustable control arms are the right way to solve a driveline vibration issue, if that is really where your vibrations are from. Adding more of a drop to what it already has ain't it.

 

[John Cooper]

Lift confirmed to be 4" (front springs 16" rear springs 12"). Motor mounts and u joints look good, bushings good and again control arms are fixed and alignment/balance just done. Anyone advise if adding washers to the existing 1.5" drop OR reducing drop may help or should I look elsewhere since the 1.5" drop-bar is there?
View attachment 585824

If you want to try, go to a 1 inch drop and see what happens.

As @lBasket the right way would be a SYE and adjustable control arms.

 

[macleanflood]

I hacked a similar looking piece of 1" square tube installed by my PO off my 97. Was very rusted and helped seize all the longer bolts in the factory nutserts. Had to cut it off with a torch and replace the nutserts with a Black Magic Brakes kit...along the way I tossed in a SYE, cheap upper rear control arms and a clutch. Then I did Curry track bars and CorrectLync steering. A year or so later I replaced all the control arms with Savvy.

-Mac

 

[mtnjam20]

Thanks again guys.

- motor mounts are NOT good...cracking in both. They appear to be stock style not MML. Sorry for bad info earlier.
- my visual and physical u joint inspection (with tires off ground) seem good.
- TC output shaft does not have a balancer
- will pick up an angle tool later today...with the tremec toolbox app and using TC and pinion locations I'm getting TC shaft around 8.6 and PIN around 10.1 but again, with my phone/app I'm not sure how accurate it is
- 1.5" tc drop is most likely rough country...there's no caps or markings but seems irrelevant at the moment.

SYE aside for the moment, motor mounts seem to be the first project. Since there's a 1.5" drop kit in place, I should go with stock style mounts and not a mount lift style correct?

 

[macleanflood]

I ordered an Anchor OEM style motor mounts and transmission mount off Rock Auto for my 97. It was like $30.

I replaced my motor mounts as I was doing a BL and MML with spacers.

-Mac

 

[GregBelleville]

I did the same as Mac last year, replaced my trans and motor mounts with Anchor brand. I added a 1" jks motor mount lift as well which will improve your drive line angle and might reduce or eliminate your vibes.

 

[OldBuzzard]

Why not verify where the vibes are coming from before fixing it blindly? Remove the rear driveshaft and drive it around in 4HI, see if the vibes went away.

 

[LONGJP2]

Lift confirmed to be 4" (front springs 16" rear springs 12"). Motor mounts and u joints look good, bushings good and again control arms are fixed and alignment/balance just done. Anyone advise if adding washers to the existing 1.5" drop OR reducing drop may help or should I look elsewhere since the 1.5" drop-bar is there?
View attachment 585824

Maybe because it's a '97, but the skid plate doesn't look stock to me.