Vibration after 2" Rough Country lift install

Holden_Caulfield

New Member
Joined
Mar 16, 2021
Messages
4
Location
North Georgia
Hey y'all,

I've read tons on this site about solutions, but I'm still not clear about it.

My 2000 4.0L Sahara automatic drove flawlessly. I had a local shop install RC longer springs and new shocks for a 2" lift. They also mounted 32" X 11.5" Cooper Discoverer AT3 XLT tires on 15x8 rims. The reason I bought that kit is because Rough Country and all of the reviews said there was no need for any modifications.

When I picked it up, the mechanic immediately told me that I needed to get extended sway bar links because they were now so tight, that I was missing a hold-down clip at the drivers side front coil, and that I should have provided them with pads to set the coils on because they'll end up squeaking.

Driving away I noticed a vibration around 25-35 mph that would only happen when I'm accelerating. My research points to the rear driveshaft angle. I don't want to lower the transfer case with washers, so I'm willing to install the 1" MML. I'm hoping someone can tell me if I'll have enough clearance to install this without a body lift, and if I'll only need to adjust the fan shroud and nothing else.

Thanks!
 
Hey y'all,

I've read tons on this site about solutions, but I'm still not clear about it.

My 2000 4.0L Sahara automatic drove flawlessly. I had a local shop install RC longer springs and new shocks for a 2" lift. They also mounted 32" X 11.5" Cooper Discoverer AT3 XLT tires on 15x8 rims. The reason I bought that kit is because Rough Country and all of the reviews said there was no need for any modifications.

When I picked it up, the mechanic immediately told me that I needed to get extended sway bar links because they were now so tight, that I was missing a hold-down clip at the drivers side front coil, and that I should have provided them with pads to set the coils on because they'll end up squeaking.

Driving away I noticed a vibration around 25-35 mph that would only happen when I'm accelerating. My research points to the rear driveshaft angle. I don't want to lower the transfer case with washers, so I'm willing to install the 1" MML. I'm hoping someone can tell me if I'll have enough clearance to install this without a body lift, and if I'll only need to adjust the fan shroud and nothing else.

Thanks!

I just got on to try to research the same problem. I just installed my 2" lift this weekend with 2" pro comp springs, .75" front coil spacers, rancho rs500xs, OME rear trackbar bracket extension, and JKS adjustable front swaybar disconnects. New tires arrive on Thursday. I've got vibes from 15-35mph, that are worst in the 20-25mph range. The vibes feel like they're coming from the front, but idk if that's accurate. I'm hoping I don't need lower control arms or a TC drop. I have 1" higher MM ready to go in, but was waiting until my Savvy BL arrived to put them in so I wouldn't have to raise the fan. I'm eager to read the replies you get.
 
I don't want to lower the transfer case with washers, so I'm willing to install the 1" MML. I'm hoping someone can tell me if I'll have enough clearance to install this without a body lift, and if I'll only need to adjust the fan shroud and nothing else.

Thanks!
You just have to relocate the fan shroud or the fan will hit it.
 
I have roughly the same lift amount and had the same vibrations u mention. When I put my mml and bl on they went away.
Thanks for the reply. I guess the MML will be the way to go, and relocate the fan shroud like Boogieman stated. It feels like a workaround and a shot in the dark though since I don't know for sure if that's the issue. I hate to just start doing random crap that I 'think' might fix it. If I knew exactly how to solve the problem, I wouldn't mind spending a little more.
 
Thanks for the reply. I guess the MML will be the way to go, and relocate the fan shroud like Boogieman stated. It feels like a workaround and a shot in the dark though since I don't know for sure if that's the issue. I hate to just start doing random crap that I 'think' might fix it. If I knew exactly how to solve the problem, I wouldn't mind spending a little more.
This is definitely a workaround. The best way to fix this would be to install a SYE and adjustable control arms. What some don’t realize is 2 inch springs may actually net 2.5 inches of lift. With such a short wheelbase, that could make a big difference. So the workaround is a t-case drop or mml or both to get the driveline angle back to factory.
 
This is definitely a workaround. The best way to fix this would be to install a SYE and adjustable control arms. What some don’t realize is 2 inch springs may actually net 2.5 inches of lift. With such a short wheelbase, that could make a big difference. So the workaround is a t-case drop or mml or both to get the driveline angle back to factory.
Yeah, mine seems like it definitely lifted higher than 2". So a SYE and adjustable control arms for the rear will complete solve the problem? Isn't the front driveshaft angle compromised too? Thanks for your input!
 
Yeah, mine seems like it definitely lifted higher than 2". So a SYE and adjustable control arms for the rear will complete solve the problem? Isn't the front driveshaft angle compromised too? Thanks for your input!
Rough Country only makes 2.5" lift springs for a TJ, not 2". I've installed several of these lifts.
 
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Tom woods sye and driveshaft fixed mine. One other issue I had was the front driveshaft nut on the output shaft loosened up on me twice. From the factory. The front shaft had never been out before I replaced it with a Tom woods. That caused a hell of a vibration that took me a while to figure out. Adjustable arms would also help with pinion angle.
 
Yeah, mine seems like it definitely lifted higher than 2". So a SYE and adjustable control arms for the rear will complete solve the problem? Isn't the front driveshaft angle compromised too? Thanks for your input!
The front driveshaft is already a double cardan so you should have no worries there. But yes, the SYE and adjustable arms will allow you to dial in the geometry to eliminate vibes.

The MML may potentially work but you may still need to drop the T-case a bit to fine tune it. I would mainly recommend it if you are already doing a body lift since it will keep everything lined up AND helps with the driveline. Otherwise, you might only need a few washers under the transfer case. Might not hurt to try it before doing anything else.
 
Yeah, mine seems like it definitely lifted higher than 2". So a SYE and adjustable control arms for the rear will complete solve the problem? Isn't the front driveshaft angle compromised too? Thanks for your input!
I did a 2.5" lift and did the MML and lowered the TC, but still had slight vibes. It was tolerable, but it still bugged me, so I decided to do the SYE, DC drive shaft and adjustable control arms and it drives like a new vehicle now. I went ahead and did a TT while I was under there so I wouldn't have to realign and get a new drive shaft when I did it down the road. Funny how a 2.5" inch lift turned into a full on build, at least for me.
 
Hey y'all,

I've read tons on this site about solutions, but I'm still not clear about it.

My 2000 4.0L Sahara automatic drove flawlessly. I had a local shop install RC longer springs and new shocks for a 2" lift. They also mounted 32" X 11.5" Cooper Discoverer AT3 XLT tires on 15x8 rims. The reason I bought that kit is because Rough Country and all of the reviews said there was no need for any modifications.

When I picked it up, the mechanic immediately told me that I needed to get extended sway bar links because they were now so tight, that I was missing a hold-down clip at the drivers side front coil, and that I should have provided them with pads to set the coils on because they'll end up squeaking.

Driving away I noticed a vibration around 25-35 mph that would only happen when I'm accelerating. My research points to the rear driveshaft angle. I don't want to lower the transfer case with washers, so I'm willing to install the 1" MML. I'm hoping someone can tell me if I'll have enough clearance to install this without a body lift, and if I'll only need to adjust the fan shroud and nothing else.

Thanks!
I had a similar issue a while ago with 2008 Grand Cherokee. In my case, the vibration suddenly appeared around 40-50 mph when accelerating.
 
***UPDATE - Problem Solved: So, I decided to try out the transfer case drop just to see if I could fix it cheap, and it worked! So for anyone with my same setup, here's what solved it.

  • Started with stock 2000 Wrangler Sahara.
  • Installed Rough Country 2.5" lift-- which is only longer springs and new shocks. (Boogeyman-you're right. It's 2.5 not 2)
  • Installed 32X11.5X15 Cooper Discoverer AT3 XLT tires on 15X8 Pacer rims.
  • Added six 5/8 flat washers under each skid plate bolt using longer 2" bolts, giving about a 1/2 inch of drop.
Just a head's up, I wondered why I needed to loosen the four transmission mount nuts. I did as told and I realized that when I re-tightened them they had shifted about a 1/4 inch, which makes sense because it changed the geometry of everything. So do that part if you try this.

Thanks for all of your input. I'm happy with the lift for what I do, but any larger lift I probably would have just done the SYE.