drive-line vibes.

[Renegade Jpr]

OK so I got the gears done in my XJ and it has developed a driveline vibe/noise/ howl thing at around 55-68 MPH there seems to be something viberation. When the gears got done I also put in a HD SYE from AA and a new CV D-shaft from six states shaft. We also reset the pinion angle. While driving at any speed if you let off the gas and get back on it there is a "THUD" comming from the rear, the harder you stomp on the gas the louder/harder the thud is.

This is a 89' Jeep Cherokee, AW4 automatic trans, NP 231 T-case, 4.56 gears, rear D35 axle, front D30. The rear axle has a full case 30 spline Detroit locker and the front has a Detroit EZ locker.

Any thoughts?...just looking for ideas, the guy that did my drivetrain work say's he'll fix it but in the mean time I what to get some answers.

 

[Renegade Jpr]

Hello.....


did everybody already leave to TDS or something.....

 

[Renegade Jpr]

Im begining to think axle wrap might be part of the problem. The rear axle is a D35 with a Yukon 30spline kit in it and a full case detroit locker + 4.56 gears. Im running a RE 1.5" block and 3" add-a-leaf all from RE.

I had it parked in my driveway and shifted it from reverse to drive and I get the same "THUD" , I opened the door and with the brakes applied I started shifting it back and forth from drive to reverse...with the door open I can hear the THUD comming from the back along with a "PING" thats slightly muffled, like to peices of steel hitting each other solidly...Im starting to think it might be the back lash on the R&P.

As for now Im off to TDS, it will be trailered there so I dont have much to worry about...I just be easy on it. I guess monday its back to the shop again!

 

[Kejtar]

Im begining to think axle wrap might be part of the problem. The rear axle is a D35 with a Yukon 30spline kit in it and a full case detroit locker + 4.56 gears. Im running a RE 1.5" block and 3" add-a-leaf all from RE.

I had it parked in my driveway and shifted it from reverse to drive and I get the same "THUD" , I opened the door and with the brakes applied I started shifting it back and forth from drive to reverse...with the door open I can hear the THUD comming from the back along with a "PING" thats slightly muffled, like to peices of steel hitting each other solidly...Im starting to think it might be the back lash on the R&P.

As for now Im off to TDS, it will be trailered there so I dont have much to worry about...I just be easy on it. I guess monday its back to the shop again!

Hmm... I don't know about the thud and ping when you're chaning gears and not moving? but I'm willing to bet money that the 1.5" block is not helping you any. Btw, is that all on a stock spring pack? if so, how does the pack look by the eyes? any bends (upwards?)

 

[Renegade Jpr]

Yea, its on the factory leaf packs.... I cant remeber how the eyes look as of right now, when I get home I'll take a look at it.

 

[Rawbrown]

I installed RE 1.5" shackles with no change so I think my next step will be to pull the cover and check the gears. if I have to, I will be installing new gears if thats the case. but we will see. I will probably pick it up on my way back from the socal XJ jambo.

 

[Kejtar]

I installed RE 1.5" shackles with no change

Shackles are one thing.. but he has blocks..

 

[Rawbrown]

yes, I installed the shackles with the blocks. BTW I am the person that has been working on his jeep. my next step is to try and take the blocks out. and have the shackles in. but I want to open it up and check the gears.

 

[Kejtar]

yes, I installed the shackles with the blocks. BTW I am the person that has been working on his jeep. my next step is to try and take the blocks out. and have the shackles in. but I want to open it up and check the gears.

lol... oh ok

 

[RCP Phx]

Most lunchbox lockers make a "thud" as described,its the "take-up" of the spider gear shaft!

 

[Xtreme XJ]

The "THUD" is more than likely backlash... As to the "howl/vibe" you might try pulling the front drive shaft & going for a drive.... when I went to 4.56s I got a harmonic vibe, I swore it was from the rear but pulled the front & it's smooth.......
Good Luck !!
Curt (aka Xtreme XJ)

 

[Rawbrown]

I pulled the front shaft. not it.... other things that were done. vacum disco block off with a one piece shaft. it has a detroit in the rear.