Noise after hack n tap

T

Treleaven

NAXJA Forum User

Location

Okanagan

• Mar 11, 2017

• #1

Hey gang,

I just finished doing the hack n tap and boy let me tell you. The jeep feel like a new ride now.

The only issue is if I give the skinny pedal a strong push, I get a vibrating sound like the drive shaft is hitting something. The sound is completely relative to the RPM's. I looked under and it is close to the ebrake cable but it doesn't look like it should hit. While doing this upgrade, I also replaced the tranny mount the so I do not think that is the issue.

Any ideas?

 

N

N8N_99xj

NAXJA Forum User

Location

Berwyn Heights, MD

• Mar 11, 2017

• #2

Keep in mind your pinion will rotate up a few degrees under heavy throttle so "close" may turn into "rubbing" at that point.

 

Tim_MN

Freakish Hand Strength

NAXJA Member

Location

Minneapolis, MN

• Mar 11, 2017

• #3

Did you shim the rear axle ?

Any sort of even slightly technical question requires complete details about the Jeep. Year, engine, transmission, transfer case ? What lift height ? Is the SYE driveshaft new or used ? Have you checked the double cardan joint and the axle yoke for signs of metal to metal contact on the yoke ears ?

 

Last edited: Mar 11, 2017

ehall

NAXJA Member

NAXJA Member

Location

Southern Maryland

• Mar 11, 2017

• #4

Did you shim the rear axle? Pinion needs to point towards the transfer case output.

One thing I found helpful is get an old digital camera and a small tripod, duct tape the tripod to something so you can point the camera at the driveshaft

 

T

Treleaven

NAXJA Forum User

Location

Okanagan

• Mar 11, 2017

• #5

The rear axle has a 2.5° shim. It is a 98 4.0 Aw4 with 231. Approximately 4-4.5" lift and it is a brand new yoke with a used front drive shaft from another XJ that has 1 new u joint.

 

ehall

NAXJA Member

NAXJA Member

Location

Southern Maryland

• Mar 11, 2017

• #6

I had 6* shims in the rear of mine with 4.5" lift

 

Tim_MN

Freakish Hand Strength

NAXJA Member

Location

Minneapolis, MN

• Mar 11, 2017

• #7

Each XJ is different, but typically you shim about 1* for each inch of lift. Double check that all the suspension components, especially the u-bolts, are torqued to the correct spec and have not loosened.

 

T

Treleaven

NAXJA Forum User

Location

Okanagan

• Mar 12, 2017

• #8

Everything is tight...pinion angle looks spot on.

I did find the issue. There is a small plastic piece that the o2 sensor wire loom goes through and it was barely rubbing on that. last night in the dark i could not see that it was getting rubbed. I notched the plastic where the rub marks were and no more noise.

Thank you all for your help.

 

V

Vernicious

NAXJA Forum User

Location

Layton, Utah

• Mar 14, 2017

• #9

Treleaven said:

The rear axle has a 2.5° shim. It is a 98 4.0 Aw4 with 231. Approximately 4-4.5" lift and it is a brand new yoke with a used front drive shaft from another XJ that has 1 new u joint.

Click to expand...

Mine has 6* shims in it, and I still get a slight vibe when I hit the throttle really hard. Otherwise it's smooth.