i didnt wanna hijack a thread so ill ask here....

M

milehigh

NAXJA Forum User

Location

Denver, CO

• May 25, 2008

• #1

i read on a recent post that was mentioning things to look out for on xj's that the 00 and 01's had low pinion front diffs. i own a 00 so that makes me a bit concerned. what is it about them that are bad? or is it that they just have a lower gear ratio and dont have as much torque when crawling? mines a dd that i use in the mountains on some mild trails camping in the summer. it gets heavy snow duty going boarding in the winter.

 

RichP

NAXJA Forum User

Location

Effort, Pa

• May 25, 2008

• #2

The low pinion offers less clearance than a high pinion, not really that much of a big deal. Of more importance to me is the head, they are prone to cracking between #1 and #2 cylinders. Look at an older XJ and then yours for the differences in pinion.

 

kj139

NAXJA Forum User

Location

Yuba City, California

• May 25, 2008

• #3

The ring gear in the low pinion is not nearly as strong as the reverse cut in the high pinion. In a "built" Dana-30, the ring and pinion become the weak link, so the stronger the better. It is the same between the TJ's and the new JK's. THe JK's have a HP front axle in contrast to the TJ's...much stronger.

If you are really concerned about it, HP Dana-30's are a dime a dozen and it is an easy swap.

Good luck!

 

M

milehigh

NAXJA Forum User

Location

Denver, CO

• May 25, 2008

• #4

thanks guys, doesnt seem like an issue for me then. if it does break ill do the swap. as far as the head goes, ill fix it if it breaks as well. i hope it doesnt crack, but someone mentioned that was for aluminum heads, if memory serves me correctly i have an iron head. or does the problem lie with both?

 

JXPEEJ

NAXJA Forum User

Location

Apple Valley Ca.

• May 26, 2008

• #5

There is no "stock" aluminum head....But don't sweat it..They can't ALL crack.

 

Hypoid

NAXJA Member

NAXJA Member

Location

Golden, CO

• May 26, 2008

• #6

Hi Robert! There has been a lot of talk about a newer head casting that seems prone to cracking. I drive a RENIX heep, so I'm not up on much of the newer stuff.

High Pinion v.s. Low Pinion: The driveline/u-joint angles get steeper as you lift. The low pinion will have driveline vibration sooner than a high pinion.

 

T

TiRod

NAXJA Forum User

Location

SW MO

• May 26, 2008

• #7

Aside from relative strength issues, the low pinion is slightly more prone to scraping a rock, if you wheel that hard. Of course, you probably would hit the rock with the diff cover first, so it's kinda moot.

Most upgrades, like to D44's, require accepting low pinions, and that doesn't seem to slow anybody down. Possibly the usual set of 32" tires offsets any minor problems.

 

JNickel101

NAXJA Forum User

Location

Alamogordo, NM

• May 26, 2008

• #8

Make sure you have a few inches of lift if you swap over to the HP30 with your 2000. Otherwise, the exhaust wont clear the top of the pinion...

That was the reason for the change...

 

Hypoid

NAXJA Member

NAXJA Member

Location

Golden, CO

• May 26, 2008

• #9

TiRod said:

Most upgrades, like to D44's, require accepting low pinions, and that doesn't seem to slow anybody down. Possibly the usual set of 32" tires offsets any minor problems.

Click to expand...

Anyone who goes to that time and expense will also correct the driveshaft angles, castor angle etc.