Diagnosing TJ after 2.5 inch Rancho lift kit install

GrandpaJeepTJ

GrandpaJeepTJ

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Mar 6, 2023
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Location
Cedarburg, WI
A couple years back, my dad and I decided we wanted bigger tires for that meaner, rugged look, as I think most novice jeep TJ owners eventually decide to do. We haven’t done any off roading yet but would like to find trails in Wisconsin and the Midwest this summer.

So, we decided to have a mechanic put a Rancho RS6503B Sport lift kit on it and got 33x12.50x17 tires/ 17x9.5 Helo wheels put on it. Ever since, I feel the ride has not been great. Some of our symptoms are below, in order of importance to me:


· First and foremost, when shifting from neutral or park to reverse, the jeep physically moves up/down. This didn’t happen before the lift I don’t remember. Is this due to lack of spacers or brackets that were supplied with the Rancho lift kit?

· When driving over 50 mph, I feel like there is some centrifugal vibration under my seat. Thinking this might be the drive shaft and the lack of a properly installed lift or lack of spacers creating a less than ideal angle?

· The traction is terrible in snow. I attribute this to the super gaudy Atturo mud terrain tires I plan on replacing soon.

· I sometimes hear knocking (presumably metal) sounds when I make turns. Maybe this is caused by improper tire/ wheel size or improper lift installation? No parts seem to have been installed besides the springs, lower control arms front & rear, and shocks. Do I need new sway or track bars?

· Sometimes it feels like I’m sitting in a teacup at Disneyworld. Maybe due to loose suspension? I feel like I’m sliding when making turns. I’ve installed the two front clamps on the sway bar, but still seems like I slide from behind.

· When braking, the vehicle tends to pull to the right. I believe I’m in need of a brake overhaul and plan going with the kit from Black Magic Brakes. Brakes are original.


With that piled on you all, I come here looking for some help and guidance from the TJ pros on how to get Grandp’s TJ back up and riding like it should be and provide recommendations on any of the issues I’m having. I’m handy, but have no background in automotive so struggle with diagnosing things, unless of course there is an obvious bolt missing, crack, leak, etc. I enjoy trying to figure things out and feel super accomplished when I can complete a repair or upgrade.

I look forward to your replies, suggestions, and the wealth of knowledge I know members of this forum have!

Thank you very much!

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Vibration probably means you have enough lift to need a slip yoke eliminator and double cardan driveshaft. Or spacers to drop the transfercase skid and readjust the transfercase linkage with a drop
plate.

The tires should be 26-28 psi roughly.it will help with traction,softer ride and even tire wear.

Is the knocking in the front? Axleshaft ujoints loose?

For the loose sliding feeling i wonder if the rear track bar and or shocks are worn out.or no rear swaybar anymore?

Welcome btw!
 
That's a very incomplete kit ($800 with no shocks). Which shocks did you go with? You need longer sway bar end links, a MML or t-case drop for vibes and make sure you do a front end alignment (DIY). I see that kit only comes with adjustable lower control arms too.
Rancho-2.5-inch-sport-lift-system-TJ-LJ-RS6503B_0.jpg
 
Last edited:
TheBoogieman said:
You need longer sway bar end links, a MML or t-case drop for vibes and make sure you do a front end alignment (DIY).
Click to expand...

Agree with the mml (motor mount lift.). The vibrations described are likely due to rear driveshaft angles. A mml may ease those angles enough to eliminate the vibes. And since 2.5 inches of lift really isn’t enough for 33s, a 1” (or better yet a 1.25” Savvy) body lift would give a little extra tire clearance, and complement the mml by eliminating the need to monkey with the fan shroud.

The knocking sound when turning is probably tire lugs on the control arms. Can be easily remedied with a few washers added to the steering stops, or just easing the steering wheel back a bit when you hear the noise.
 
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After my lift, my stock sway bar links pulled apart when I was driving. I had already ordered adjustable front and rear links but they were in the mail somewhere. It felt like I was driving a boat around corners.

view
 
Last edited:
Agree with what folks said so far.

1. You need to get better sway bar links, longer or adjustable.

2. Check your tire pressure, I have 35’s and run 26. Look up mud tire chalk test, to find what yours should be, I’d guess in the 26-28 range, but that’s a guess.

3. Your vibes are rear DS angle most likely. You can go all in and get a SYE and CV driveshaft (Double Cardan) its $$$. Or a Transfer Case drop or a Motor mount lift. Those are the 3 Main options to solve.

4. I would check Toe in alignment, you can do at home, there is a good write up from Jerry in the How To section.

Once you do that, then look and make sure everything is tight, steering test. The bigger tires can stress control arm bushing (uppers we’re not replaced) or your Tie Rod Ends. Your steering is stick as well, with bigger tires may want to plan a ZJ steering or Currectlync upgrade.
 
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The vibration is definitely a common after-effect from installing a suspension lift like your 2.5" from Rancho. It's caused by the u-joints on the rear driveshaft vibrating due to the excessive angle they are now working into with the rear driveshaft's now steeper angle.

There are possible three fixes depending on your budget and mechanical skills. From lowest cost and easiest to install to highest cost and most complexity. Of course the order of desirability also goes in the same order.

1) Install a transfer case lowering kit which consists of six spacers that are inserted between the skid plate under your transfer case and the frame, the six mounting bolts pass through them. Looks like this, and they are not expensive. This works by reducing the angle of the rear driveshaft which reduces the excessive angle the driveshaft's u-joints have to work into which stops them from vibrating. This also of course causes a 1" loss of ground clearance beneath the skidplate... if that's important to you as it is to most offroaders.

Transfer Case Drop.JPG


The next most desirable fix is a pair of motor mount lifts. They lift the front of the engine 1" which tips the engine/transmission/transfer case angle a bit to lower the rear transfer case output shaft the rear driveshaft connects to. It works to reduces the angles much like a transfer case drop but without the resulting loss of ground clearance. This also gives the engine's oil pan 1" more ground clearance, a very good thing. You can buy motor mount spacers from https://savvyoffroad.com/product/sav-mmltj/ or if your motor mount rubber bushings are getting old you can get a pair of complete motor mounts with the 1" lift benefit from https://mountainoffroad.com/collect...f-motor-mount-kit-for-1-lift-97-06-yj-tj-lj-1

Best of all but also most expensive is to install a SYE (slip yoke eliminator) kit into the transfer case and replace the rear factory driveshaft with an aftermarket double-cardan driveshaft. It also requires new adjustable length control arms in the rear because the rear axle's pinion angle has to be raised up significantly to match the requirements of the new rear DC driveshaft. This is what those of us with 4" or taller suspension lifts run. Fortunately, cost and labor-wise, this is not really needed for just a 2.5" lift but if you ever get to 4" of suspension lift then it would be required.

Personally, I'd go with motor mount lift blocks if your existing motor mounts are in good condition. This is a good solid fix that doesn't lose ground clearance. Good luck with it all! :)
 
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Rickyd said:
Vibration probably means you have enough lift to need a slip yoke eliminator and double cardan driveshaft. Or spacers to drop the transfercase skid and readjust the transfercase linkage with a drop
plate.

The tires should be 26-28 psi roughly.it will help with traction,softer ride and even tire wear.

Is the knocking in the front? Axleshaft ujoints loose?

For the loose sliding feeling i wonder if the rear track bar and or shocks are worn out.or no rear swaybar anymore?

Welcome btw!
Click to expand...

Thanks Rickyd. I will check the tire pressures this weekend on the Mud tires and see where they are at. I just ordered some all terrains that will be better in snow and on the road. I went with the 33"x10.5x15 bf goodrich all terrain. I also ordered some of the 15"x8" mammoth rims off of extremeterrain.

I will check the u joints as well to make sure they are tight.

The swaybars are still there, but i think as guys posted below, the links need to be replaced. They are the OEMs. I'm not sure about the track bar. Will need to look at that. Shocks are new with lift kit a few years back.
 
Jerry Bransford said:
The vibration is definitely a common after-effect from installing a suspension lift like your 2.5" from Rancho. It's caused by the u-joints on the rear driveshaft vibrating due to the excessive angle they are now working into with the rear driveshaft's now steeper angle.

There are possible three fixes depending on your budget and mechanical skills. From lowest cost and easiest to install to highest cost and most complexity. Of course the order of desirability also goes in the same order.

1) Install a transfer case lowering kit which consists of six spacers that are inserted between the skid plate under your transfer case and the frame, the six mounting bolts pass through them. Looks like this, and they are not expensive. This works by reducing the angle of the rear driveshaft which reduces the excessive angle the driveshaft's u-joints have to work into which stops them from vibrating. This also of course causes a 1" loss of ground clearance beneath the skidplate... if that's important to you as it is to most offroaders.

View attachment 406166

The next most desirable fix is a pair of motor mount lifts. They lift the front of the engine 1" which tips the engine/transmission/transfer case angle a bit to lower the rear transfer case output shaft the rear driveshaft connects to. It works to reduces the angles much like a transfer case drop but without the resulting loss of ground clearance. This also gives the engine's oil pan 1" more ground clearance, a very good thing. You can buy motor mount spacers from https://savvyoffroad.com/product/sav-mmltj/ or if your motor mount rubber bushings are getting old you can get a pair of complete motor mounts with the 1" lift benefit from https://mountainoffroad.com/collect...f-motor-mount-kit-for-1-lift-97-06-yj-tj-lj-1

Best of all but also most expensive is to install a SYE (slip yoke eliminator) kit into the transfer case and replace the rear factory driveshaft with an aftermarket double-cardan driveshaft. It also requires new adjustable length control arms in the rear because the rear axle's pinion angle has to be raised up significantly to match the requirements of the new rear DC driveshaft. This is what those of us with 4" or taller suspension lifts run. Fortunately, cost and labor-wise, this is not really needed for just a 2.5" lift but if you ever get to 4" of suspension lift then it would be required.

Personally, I'd go with motor mount lift blocks if your existing motor mounts are in good condition. This is a good solid fix that doesn't lose ground clearance. Good luck with it all!
Click to expand...

Jerry Bransford said:
The vibration is definitely a common after-effect from installing a suspension lift like your 2.5" from Rancho. It's caused by the u-joints on the rear driveshaft vibrating due to the excessive angle they are now working into with the rear driveshaft's now steeper angle.

There are possible three fixes depending on your budget and mechanical skills. From lowest cost and easiest to install to highest cost and most complexity. Of course the order of desirability also goes in the same order.

1) Install a transfer case lowering kit which consists of six spacers that are inserted between the skid plate under your transfer case and the frame, the six mounting bolts pass through them. Looks like this, and they are not expensive. This works by reducing the angle of the rear driveshaft which reduces the excessive angle the driveshaft's u-joints have to work into which stops them from vibrating. This also of course causes a 1" loss of ground clearance beneath the skidplate... if that's important to you as it is to most offroaders.

View attachment 406166

The next most desirable fix is a pair of motor mount lifts. They lift the front of the engine 1" which tips the engine/transmission/transfer case angle a bit to lower the rear transfer case output shaft the rear driveshaft connects to. It works to reduces the angles much like a transfer case drop but without the resulting loss of ground clearance. This also gives the engine's oil pan 1" more ground clearance, a very good thing. You can buy motor mount spacers from https://savvyoffroad.com/product/sav-mmltj/ or if your motor mount rubber bushings are getting old you can get a pair of complete motor mounts with the 1" lift benefit from https://mountainoffroad.com/collect...f-motor-mount-kit-for-1-lift-97-06-yj-tj-lj-1

Best of all but also most expensive is to install a SYE (slip yoke eliminator) kit into the transfer case and replace the rear factory driveshaft with an aftermarket double-cardan driveshaft. It also requires new adjustable length control arms in the rear because the rear axle's pinion angle has to be raised up significantly to match the requirements of the new rear DC driveshaft. This is what those of us with 4" or taller suspension lifts run. Fortunately, cost and labor-wise, this is not really needed for just a 2.5" lift but if you ever get to 4" of suspension lift then it would be required.

Personally, I'd go with motor mount lift blocks if your existing motor mounts are in good condition. This is a good solid fix that doesn't lose ground clearance. Good luck with it all! :)
Click to expand...

Thanks for the reply, Jerry. I will give the replacement motor mounts with a 1" lift a try! I'm betting this will help big time. The kit i bought came with the spacers, but i just noticed a few months ago when i was replacing the transmission pan and oil pan that they were never installed! I like the idea of the motor mount lift as opposed to purchasing new spacers and dropping the skid plate. What's your take on the Brown Dog motor mounts? Just as good as the Bomb Proof ones? Saw someone installing these on a 4.0. https://browndogindustries.com/browndogindustries.com/Wrangler-TJ-40L-3.aspx
 
TheBoogieman said:
That's a very incomplete kit ($800 with no shocks). Which shocks did you go with? You need longer sway bar end links, a MML or t-case drop for vibes and make sure you do a front end alignment (DIY). I see that kit only comes with adjustable lower control arms too.
View attachment 406161
Click to expand...

Thanks Boogieman. What sway bar links do you like? There are so many options out there. Any recommendations?
 
GrandpaJeepTJ said:
Thanks for the reply, Jerry. I will give the replacement motor mounts with a 1" lift a try! I'm betting this will help big time. The kit i bought came with the spacers, but i just noticed a few months ago when i was replacing the transmission pan and oil pan that they were never installed! I like the idea of the motor mount lift as opposed to purchasing new spacers and dropping the skid plate. What's your take on the Brown Dog motor mounts? Just as good as the Bomb Proof ones? Saw someone installing these on a 4.0. https://browndogindustries.com/browndogindustries.com/Wrangler-TJ-40L-3.aspx
Click to expand...

I've had the Brown Dog motor mounts on my LJ for the past 10K miles and they have worked just fine.
 
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GrandpaJeepTJ said:
Thanks for the reply, Jerry. I will give the replacement motor mounts with a 1" lift a try! I'm betting this will help big time. The kit i bought came with the spacers, but i just noticed a few months ago when i was replacing the transmission pan and oil pan that they were never installed! I like the idea of the motor mount lift as opposed to purchasing new spacers and dropping the skid plate. What's your take on the Brown Dog motor mounts? Just as good as the Bomb Proof ones? Saw someone installing these on a 4.0. https://browndogindustries.com/browndogindustries.com/Wrangler-TJ-40L-3.aspx
Click to expand...
I'd say the Brown Dog mounts I had a set of years ago were nowhere near the beefiness and vibration isolation ability of the Bombproof mounts I later installed. But since you already have the motor mount spacers that came in your suspension kit I'd install them.
 
GrandpaJeepTJ said:
Thanks for the reply, Jerry. I will give the replacement motor mounts with a 1" lift a try! I'm betting this will help big time. The kit i bought came with the spacers, but i just noticed a few months ago when i was replacing the transmission pan and oil pan that they were never installed! I like the idea of the motor mount lift as opposed to purchasing new spacers and dropping the skid plate. What's your take on the Brown Dog motor mounts? Just as good as the Bomb Proof ones? Saw someone installing these on a 4.0. https://browndogindustries.com/browndogindustries.com/Wrangler-TJ-40L-3.aspx
Click to expand...
make sure you raise and redrill the fan shroud mounts if you lift the motor
 
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Rickyd said:
make sure you raise and redrill the fan shroud mounts if you lift the motor
Click to expand...

True, if no body lift is installed. But a 1" or 1.25" body lift has been suggested to help clear the 33" tires with only a 2.5" suspension lift, and the body lift would eliminate the need to monkey with the fan shroud
 
Just an update everyone:

1) new 15x8 wheels with 33”x10.50x15 AT tires will be put on this week. Looking forward to the difference in the feel on pavement.
2) 1” body lift from Rough Country & 1” lifted MORE motor mounts ordered. Will be installing this weekend.
3) New fixed sway bar links ordered for front and back. Will install this weekend.
4) bump cap and replacement bumps stops for front ordered.


Question: does anyone know what width the bump stop spacers are on the Rancho lift kit? They came with spacers, but doesn't appear they were installed by mechanic.

B915B852-B9CD-44B5-8187-97978DAB23CB.jpeg
 
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The bump stop cups and rubber snubbers appear to be missing entirely...

You need to set it up so the metal cups which are missing hit the bottom pad before the shock bottoms out.best way to do that is adding spacers to the lower pad.

Cut off the shock covers and toss em.they just hold water and rust the shock
 
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Rickyd said:
The bump stop cups and rubber snubbers appear to be missing entirely...

You need to set it up so the metal cups which are missing hit the bottom pad before the shock bottoms out.best way to do that is adding spacers to the lower pad.

Cut off the shock covers and toss em.they just hold water and rust the shock
Click to expand...

The rancho 2.5” kit only came rear Bump stop spacers. Would there be a reason they didn’t include front spacers? I’ve got the cup and bumps on the way, but no spacers yet. mostly because I’m not sure what size and that I thought maybe rancho just knew I didn’t need them for the front?
 
GrandpaJeepTJ said:
maybe rancho just knew I didn’t need them for the front?
Click to expand...

No. There are no all inclusive lift kits for our jeeps. Its a process that needs to be followed.

Measure exposed shock shaft at ride height and distance from bump cup to lower pad. Add bump until that distance is shorter than the exposed shock shaft.same for the rear.

The rubber bumper in the cup doesn't count. It is made to compress into the cup entirely
 
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