Will I need to make some driveline changes after installing 2.5 inch springs?

DUB

TJ Enthusiast
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Jun 1, 2023
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Eastern Washington
Sooo, bought a new to me 2002 TJ (154K mi), a few weeks ago (first Jeep)... Things done since: new shocks, steering stabilizer, cat back exhaust, modified 3rd cat, seat covers, longer front sway bar links, replaced multi function switch and have a Jeep air kit on order. Love the rig it's fun to drive!

Q: Jeep came with 2" puck spring spacers. I have since ordered 2.5" longer springs to replace, as I figured the old springs are probably shot.. There is no rear track bar relocate, SYE or transfer case drop done to this Jeep so far. Do you think I should be prepared for some drive shaft harmonics after changing the springs and removing the spacers?

Want to thank you guys, almost every question I have run across with this rig has been answered from this forum. I know this one has been addressed as well but can't find anything from 2"-2.5" changes.

Thx!
 
Sooo, bought a new to me 2002 TJ (154K mi), a few weeks ago (first Jeep)... Things done since: new shocks, steering stabilizer, cat back exhaust, modified 3rd cat, seat covers, longer front sway bar links, replaced multi function switch and have a Jeep air kit on order. Love the rig it's fun to drive!

Q: Jeep came with 2" puck spring spacers. I have since ordered 2.5" longer springs to replace, as I figured the old springs are probably shot.. There is no rear track bar relocate, SYE or transfer case drop done to this Jeep so far. Do you think I should be prepared for some drive shaft harmonics after changing the springs and removing the spacers?

Want to thank you guys, almost every question I have run across with this rig has been answered from this forum. I know this one has been addressed as well but can't find anything from 2"-2.5" changes.

Thx!

The amount of lift you actually get can vary from the advertised lift amount. 2-3” is a gray zone. If you do get vibes, usually a MML will solve it. That would require you to raise your fan shroud ~1”. Welcome to the forum.
 
Welcome to WTF!

First, what is a Jeep air kit? If that means you bought a cold air intake with a K&N air filter, I wouldn't install it. A K&N air filter is notorious for allowing a lot of dirt, silica, and fine dust into the engine. Not to mention that while a cold air intake sounds good in theory it won't actually boost performance in a Wrangler. Really.

I'd remove the spring spacers and run nothing but the 2.5" springs. Yes that 2.5" of suspension lift can cause drivetrain vibrations. However you can install a pair of 1" motor mount lifts like the Bombproof motor mount lifts with rubber bushings from Mountain Offroad Enterprises which will straighten the excessive angle at the rear driveshaft that causes the vibrations. Or you can install a 1" transfer case skidplate drop kit which does the same thing with a different method but causes a 1" loss of ground clearance.

You won't need a SYE with only 2.5" of suspension lift, that's a normal need once you get to 4" of suspension lift though. :)
 
Welcome to WTF!

First, what is a Jeep air kit? If that means you bought a cold air intake with a K&N air filter, I wouldn't install it. A K&N air filter is notorious for allowing a lot of dirt, silica, and fine dust into the engine. Not to mention that while a cold air intake sounds good in theory it won't actually boost performance in a Wrangler. Really.

I'd remove the spring spacers and run nothing but the 2.5" springs. Yes that 2.5" of suspension lift can cause drivetrain vibrations. However you can install a pair of 1" motor mount lifts like the Bombproof motor mount lifts with rubber bushings from Mountain Offroad Enterprises which will straighten the excessive angle at the rear driveshaft that causes the vibrations. Or you can install a 1" transfer case skidplate drop kit which does the same thing with a different method but causes a 1" loss of ground clearance.

You won't need a SYE with only 2.5" of suspension lift, that's a normal need once you get to 4" of suspension lift though. :)

No air box mod, Jeep Air, A/C kit. Didn't come with factory A/C and I live in the desert! lol

Had a concern about the MML kit with now installing A/C and how everything would line up?

I like how you all say, "once you get a 4" lift"... Like a boat, never big enough!
 
No air box mod, Jeep Air, A/C kit. Didn't come with factory A/C and I live in the desert! lol

Had a concern about the MML kit with now installing A/C and how everything would line up?

I like how you all say, "once you get a 4" lift"... Like a boat, never big enough!
Great, glad to read you're not installing a CAI kit.

A MML won't affect the installation of an a/c kit. However the engine fan will be 1" higher after the MML is installed which means the fan shroud on the radiator will have to be moved up 1" or a 1" to 1.25" body lift needs to be installed which will also raise the fan shroud. Raising the fan shroud 1" is easier and free though, you just drill new mounting bolt holes in the shroud 1" lower than where they are now.
 
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Welcome to the forum. If you go the MML route, I have a new one you can have for shipping costs only.

Thanks! I think I'm going to rip out some 1" spacers here in the shop incase I need them for the install this weekend. If I do decide to go SYE, can I eliminate all of these (MML/TC drop)? Maybe just invest in it sooner than later..?
 
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Thanks! I think I'm going to rip out some 1" spacers here in the shop incase I need them for the install this weekend. If I do decide to go SYE, can I eliminate all of these (MML/TC drop)? Maybe just invest in it sooner than later..?

A SYE requires adjustable rear control arms. No need for a MML/TC drop with those. If you're only doing a 2- 2.5" lift, you shouldn't need a lot of extra expenses, unless you want them. It's your Jeep and you can spend money anyway you want to.
 
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A SYE requires adjustable rear control arms. No need for a MML/TC drop with those. If you're only doing a 2- 2.5" lift, you shouldn't need a lot of extra expenses, unless you want them. It's your Jeep and you can spend money anyway you want to.

Just knowing how I am... I'm guessing 35's are in my future, so I might want to head down that path!
 
Can I also ask you guys about gearing for this Jeep? It's a dog with stock gears and 33's.. Can I just ring and pinion the 30/35 to a 4.56 or 4.88 to get the take off and highway speeds needed and get around in the hills a bit? I don't rock crawl, just off road a bit.
 
new shocks? did you go with a stock length/ oem style. 2.5" will put you at the outside if the range of stock- still can run them but you are loosing out on the droop. 2.5" spring i had a ever so slight drive line vibe- a little time to settle/bigger spare and all is well now
 
new shocks? did you go with a stock length/ oem style. 2.5" will put you at the outside if the range of stock- still can run them but you are loosing out on the droop. 2.5" spring i had a ever so slight drive line vibe- a little time to settle/bigger spare and all is well now

No I bought Rancho shocks that were for 2-3" lift. Already had 2" spacers on it.
 
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Can I just ring and pinion the 30/35 to a 4.56 or 4.88 to get the take off and highway speeds needed and get around in the hills a bit? I don't rock crawl, just off road a bit.

Sure you can.