j4mison

EDIT: Now i need help dropping my crossmember.. check last post!


So this week I installed my 4.5' Zone Offroad lift, i had it taken in to the shop and they torque'd all the bolts to spec and made sure I did everything right, and now I can finally drive it!

Everything is fine so far, except around 40-50mpg, this weird almost grinding noise comes from under the jeep.

YES, I know this is referenced in about a million threads already, and YES, I have looked through all of them. The "most common" cause is needing an SYE or a tcase drop.. My jeep is 2WD, (4wd conversion coming soon..) so i cant actually drop the t case lol. Any ideas on what this noise is, and or what I can do to reduce the noise and fix it?

p.s. I dont know if it helps, but I need to relocate my trackbar still. Would this cause the grinding noise...? I know it pulls because of that but i've never heard of the noise until now.

TenPercentXJ

You still have a cross member to hold the tranny up. All a t-case drop does it drop the cross member to allow for better angles. I bet you could fab your own or use a T-case drop kit from one of the many companies who sell them.
Your AW4 has a slip yoke as our 231/242s do and will still have the same issues. Are you leaking tranny fluid out of the yoke? You also could get an angle measuring tool and try to shim your leafs to achieve a closer to stock pinion angle.
Other options are try and find a 2wd Dakota rear driveshaft and see if it will fit or have yours lengthened. Both of these options are pricey compared to shims/drops and you should save your money for a T-Case and front axle

j4mison

I actually got a 1" tcase drop with my lift! I didn't know about the crossmember/tcase drop though, I just thought I didnt need to worry about it because of the whole 2wd thing. The tcase drop literally looks like 2 blocks of metal with some bolts.. all i would be doing is unbolting the existing crossmember and bolting it in with those acting as spacers? is this something I can do, or do I need to take it in somewhere and have them do it?

afaik, i am not leaking any tranny fluid or anything.. however, i have only been driving on this for today.. I suppose it could show up in the next few days.

TenPercentXJ

They are pretty self explanatory. Look up directions for how to drop them and gauge your skill level on what you read. It's a pretty basic proceedure, if you put your lift in you can drop your crossmember.
Is your noise at accel or decel?

j4mison

the noise is weird, its right at about 45 mph, and i think if i hold down the gas, nothing happens until i let go. Once i let off the gas, as I let all the way off, it begins and then stops shortly after. Then if i accel and im going >45, the noise begins again. Almost like a transmission issue..?
My transmission has been fine thus far and the jeep is a well maintained, <100k miles xj.

i will definitely look up and probably drop the crossmember tomorrow! if i look it up now i'll get all ancey won't be able to sleep haha

TenPercentXJ

Cool, it should help. It will be a decent enough temp fix until you convert to 4wd. When you do convert save the money up front and S.Y. eliminate the T-case before you even install it. While your under there tomorrow check your driveshaft u-joints too. If your under 100k they are probably original and depending on how you drive and where you live they MAY be wonky, it's a good chance they are OK however.

Tsaani97xj

What you are experiencing is 100% driveline vibes. You will need to adjust your angles to compensate for the change. Shims at the rear axle and lowering your crossmember. The problem with TC drop kits is they are not adjustable. I used heavy washers and found that the thickness of a single washer can throw it off.

With that said since you are 2wd you may be able to just shim the axle. Learned this some 25 years ago on my lowrider S10.

For the rest. I realize that isnt the only problem with a TC drop but is the reason they dont solve a lot of users problems. Been fine for me for over 50k miles but no hard core wheeling. Not wise to use your DD as a toy.

OP, best of luck.

jay_sco

Pretty sure it was clarified in your other thread that although you don't have a TC, the crossmember is still the same. Oh well, now you know. FWIW, I started with a 3/4" drop and it eliminated the noise, same scenario that you have, getting ready to remove the 3/4" and replace with a 1/2" drop.
When you say "relocate" the track bar, what exactly to you mean? At 4.5" I'd invest in an adjustable double shear track bar.

j4mison

I had them checked whenever they went over the lift, they said they were fine and no need to replace them - since I am in North Texas, rust is usually not a problem here, and also since the xj is 2wd, most of its life I think it was driven by some grandpa just around town... The interior is immaculate and no rust on the underside at all - I got incredibly lucky.

I believe the drop it gave me is a 1" tcase drop.. should I fab up something less, or try that and see what happens?

On the lift, the instructions came with some bolts and a page that told me to basically move the trackbar mounting location over by 3/4". This is supposed to basically return it to stockish location..?

Driveline vibes are usually vibes though, right? I don't have any vibes at all, just that one noise that freaks me out. I have no wobble or vibes at all, that I know of.. I've only gotten up to 55 so far and like i said, no vibes, solely noises. I dont go hard core wheeling much, and to be honest, it is mostly built as a mall crawler/weekend warrior... I dont go through anything hardcore, and no rocks at all, only mud.
Down in Texas we have **** for rocks, but we do have tons of mud!

TenPercentXJ

I'd recommend not relocating your track bar and buying a new one with a mount. Relocating is a trashy half *** fix meant to save money. It will help with your axle alignment but it will be weak and could cause DW.

Tsaani97xj

Using vibes is misleading some. While it can create slow vibrations, a lot of time in my experience, because of how fast the driveshaft spins it comes off like a grinding or buzzing feel. If you reduce your rear driveline angles appropriately that grind will go away.

j4mison

Okay guys, slightly different problem - upon lowering my crossmember, I stripped the hell out of the retaining studs. I looked up all these threads on how to remove the stud and everything, and it doesn't make any sense to me - I know about the double nut method, but how the hell do i reach that stud!? I don't want to be drilling through my floor or anything.


edit: these are the pics of both sides of my x member. you can see the one stud i'm having trouble removing in the first pic

TenPercentXJ

Drill, tap, and get a new grade 8 bolt, try 7/16. It's a simple but time consuming fix, you'll be drilling for awhile.

studmuffin

To get that bolt that is sticking out just grab it with locking pliers and twist it off. Doesn't matter if you damage the threads you will replace them anyways.

jay_sco

Vise grips or small pipe wrench.