new gears, new noise

hey all,

just picked up the XJ from gettin some work done. Super 44 kit installed with 4.88s (yukon) and detroit in rear. super 30 with 4.88 to match and ARB in front. all seals/beaings/etc were replaced.

i have a brand new set of BFG muds 35" that ive had for a week or so.

when i first picked it up it vibrated a lot, but it has gotten MUCH better. now it makes some noise after 60mph. at 75 the drone is very deep and resonant. the rearview mirror vibrates with the resonance.

this noise was not their before. only problem i know of is a worn out CV on the front d/s. i can hear it chatter at low speeds.

is this normal with new gears? i have only put 180 miles on them so far.

-Tim

it very well may be one of the driveshafts since they are turning faster

skyjackedxj96 said:

it very well may be one of the driveshafts since they are turning faster

Click to expand...

the rear one is a pretty new tom woods and the front one does have the bad CV that chatters. i wanted to pull the front shaft to see if it goes away, but one of the d/s bolts on the transfer case end is rounded...i lost my vise grips and those things arent cheap. whats the best way to get that bolt out? will vise grips do it?

-Tim

The drive shafts are not spinning faster with 4.88 and 35s compared to stock gears and stock tires.

I hope you didn't take a new set of gears out on the highway and run the crap out of 'em without proper break-in.:doh:

Did you also happen to put a new lift on when you did the gears?? What year/engine/trans combination?

Ditto...
more info please. do you have an SYE? what tires were you running before? is your dog gay? some of those things matter.
gears don't F'up and cause a vibrator....bzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz...
what year is your jeep? do you have a disconnect front axle?

i have had a 5" lift for a while. AA sye tom woods in rear, had them all for a while..

4.0, auto, np231 non disco front axle.

installer did an initial break in, drove it about 20 mins and let it cool.
he told me all i needed to do after that was not do any towing or racing or wheelin for 500 miles and then change the fluid.

then i drove it a few short trips and let it cool. then i had to get home and drove on the highway.

If it didn't have the vibration BEFORE the gear change...maybe the front drive shaft is out of index if it fell apart when he took it out.

If you were running 35s on the stock gearing, the shafts ARE spinning faster than before the regear. BUT the shaft speed will still be very close to stock.

Well I would try the driveshafts first. And I had no choice after my gear swap to hit the highway for 70 kilometers @100km/h after my gear install. Had to get home and no problems with mine.

twisted_ed said:

Well I would try the driveshafts first. And I had no choice after my gear swap to hit the highway for 70 kilometers @100km/h after my gear install. Had to get home and no problems with mine.

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im trying to get the driveshaft out. that rounded bolt is giving me fits.

i drove a few short trips, but i also had to hit the highway to get home, i dont even know if backroads would get me from there to here.

i have heard lots of good things about this installer especially when it comes to gears, thats why i have not mentioned a name yet as i do not think it is the gears or the install. im really leanin toward the front d/s

-Tim

Inject some grease into the cardan ball on the front DS. A needle can be inserted under the sleeve and up under the ball. If you have a chirping or noisy front DS it needs grease. Grease the u-joints as well so you have a smooth spinning DS. Also check the pinion angle on your front DS and adjust your upper and lower control arms accordingly. Disconnect the front axle end first and you can rotate the cardan side of the DS to get better access to the stuck bolt. Replace them ALL (including the straps) and tighten the new ones to 14 ft pounds for the axle side and 20 pounds for the TC side. They are metric by the way if you tried to use SAE sockets or wrenches on them. 8mm for the axle side and IIRC 10mm on the TC

by the sounds of it, I doubt its a bad install.

Rocketman said:

They are metric by the way if you tried to use SAE sockets or wrenches on them. 8mm for the axle side and IIRC 10mm on the TC

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I don't think so...all those Spicer CV companion pieces have standard thread (5/16 UNC on the t-case side I believe), and same for the pinion yokes. 5/16" is the wrench I always used for the strap-style yoke and 1/2" for the u-bolt style.

I have had the same problem with rounding the bolts. About the only choice you have is to get a file (or dremel) and file out either a slot in the end to use a screwdriver in, or make new sides. I am looking to either replace mine with 12 points, allen, torx or get a 6 point wrench

hey all,

finally got the front d/s out. it took a brand new set of vise grips, the old ones just wouldnt grab it.

the front joint had a lot of play in it, so it probly is bad. how does one go about servicing a front d/s cv joint?

with the front d/s out, it was smooth as butter.

-Tim

jeepnuts311 said:

hey all,

finally got the front d/s out. it took a brand new set of vise grips, the old ones just wouldnt grab it.

the front joint had a lot of play in it, so it probly is bad. how does one go about servicing a front d/s cv joint?

with the front d/s out, it was smooth as butter.

-Tim

Click to expand...

get a new cv joint. vise grips arn't expensive

While you have the drive shaft out, check and make sure the yoke (nut) on the TC is tight. If this is loose, you'll experience some vibrations.

Les

LBEXJ said:

While you have the drive shaft out, check and make sure the yoke (nut) on the TC is tight. If this is loose, you'll experience some vibrations.

Les

Click to expand...

Does this happen much as I suspect my father XJ to have a loose yoke nut too? It is leaking some oil from it and there does feel like it has some play. I have the same problem that someone had rounded off one of the bolts and couldn't get it un-done to check tension just before they left on there 3 month holiday with it.

Gojeep said:

Does this happen much as I suspect my father XJ to have a loose yoke nut too? It is leaking some oil from it and there does feel like it has some play. I have the same problem that someone had rounded off one of the bolts and couldn't get it un-done to check tension just before they left on there 3 month holiday with it.

Click to expand...

I really do not know if this is a common problem or not, but it happened to me. I found the suggestion to check the yoke nut doing a "driveline vibration" search, and sure enough it was loose. Although it did not completely cure the vibration I was having, it made a dramatic improvement in it. Now why it came loose ... :dunno:

Les

just an update,

after i pulled the old driveshaft with the worn CV, the noise and vibes went away. i just got a new driveshaft today that looked to be in great condition out of a 94 ZJ, it was the exact same length.

after i put in the new driveshaft, i started driving and there was a slight "whirring" noise in the t-case i could hear everything spinning, it doesnt grind but i can hear it spinning, only way i can describe it is whirring

no vibes at all until 65+mph then it starts droning, it sounds like someone with loud bass and a rattling trunk lid, cant feel the vibes very much, but it it hell on my ears

so i dropped the shaft back out and checked the yoke nut on the front output of the tcase and it was slightly loose, so i retorqued it.

my front pinion is at 0* in relationship to the driveshaft (points directly at yoke)

when i had 33s and 3.55 gears the driveshaft didnt make noise but with 35s and 4.88s i get the droning above 65mph, so im guessing the RPMs with the 3.55s never got high enough (probly woulda had to go 95 to get the same RPMs)

the last thing i can think of is a bad output bearing on the front of the t-case. any other suggestions?

TIA
-Tim