Dana 30 Pattern Check

I've been wrenching on my '97 XJ for a few years now and I've learned a lot from reading posts on this forum, so I appreciate any input!


I'm in the process of re-gearing and installing an ARB in my Dana 30. This is my first time setting up gears. I think I am close, but would appreciate any feedback.


My backlash is 0.007".


Coast:




Drive:

Pattern looks very good to me.
Backlash spec is 6 to 10 thousands,
I don't think you could get it any better.
Good job!

Yup, looks good to me also. I recently rebuilt mine and ended up with .007" backlash and a similar pattern. Coast side was a little bit off center but should still be good to go.

How is your preload torque?

I appreciate the feedback. I used a set-up inner pinion race so I'm going to install the real race later. During set-up, I've been using 15 in-lbs of rotating torque for pinion preload, although I still need to dial the shim stack for this in to get the correct torque on the pinion nut. My understanding is that the pinion nut torque doesn't affect the pattern as long as the pinion preload is sufficient.

I've also been using "a few hits with a dead blow" of carrier preload. I know the "right" way is to use a case spreader, but many many people online seem to think it isn't necessary. My original D30 carrier had no preload - it just fell out after I took the bearing caps off.

Welcome.
Looks good, I’d run it.
If it was a rear, I would try taking 5 thou out.

Thanks all! My pinion preload was 15 in-lbs of rotating torque during setup, but I haven't dialed it in when it comes to the pinion nut torque. My understanding is that pinion nut torque doesn't affect the pattern as long as it's "pretty tight" and the preload is in spec.

My carrier preload is "a few whacks with a deadblow". I know the "right" way is to use a case spreader, but most people don't seem to think it's necessary. The stock D30 carrier had no preload - it just fell out when I took the bearing caps off!
Thanks again, I'll check back when I finish the rest of the installation.

grantb said:

Thanks all! My pinion preload was 15 in-lbs of rotating torque during setup, but I haven't dialed it in when it comes to the pinion nut torque. My understanding is that pinion nut torque doesn't affect the pattern as long as it's "pretty tight" and the preload is in spec.

My carrier preload is "a few whacks with a deadblow". I know the "right" way is to use a case spreader, but most people don't seem to think it's necessary. The stock D30 carrier had no preload - it just fell out when I took the bearing caps off!
Thanks again, I'll check back when I finish the rest of the installation.

Click to expand...

My preload was similar with a fairly tight yoke. 20 IN/lbs (new bearings) and 210 ft/lbs on the nut.

I had to give my carrier several good whacks to get it in. I hope I don't have it too tight.

Mine also just about fell out on disassembly. Just a light push with my pry bar.

Sounds like that carrier preload is right in the spec range.

Pattern looks good

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Nobody uses carrier spreaders on small stuff like a dana30. What you describe is what most consider “good carrier preload”.
More important than pinion nut torque, is using a brand new nut with a good amount of red loctite.

Got around to finishing this installation. The pinion preload needed two attempts, as for some reason my preload almost vanished after I put the seal in the first time. I measured 15 in-lbs, installed the seal, and all of a sudden measured 3 in-lbs. My theory was that I didn't oil the pinion bearings enough during set-up - just a thin coat. I oiled them generously after that.
My 2nd pinion preload attempt ended up with 25 in-lbs of preload - before and after installing the seal. I didn't have to adjust backlash at all.
Now I have to clean up my garage and get ready for the 8.25! There are fewer resources on the ARB-specific installation, but it also looks like an easier axle to work with in general since there are no preload shims or carrier shims.

When chasing your tail with pinion preload, there are two things you must be on the lookout for, as both will loosen up once back on the road, resulting in a lack of pinion preload which lets the gears move around, and massive failure.
1- the pinion bearing races being seated in 100%, when installing these races, make sure the pocket in the axle is clean with brake clean. Then once it’s all installed nice and tight, give her an extra whack or two on your bearing race drivers.
2- the pinion bearing slightly coming off the pinion. If your doing something with an oil slinger on the pinion under the bearing, try to spin the slinger. It should be tight tight tight. Sometimes these will loosen up after a couple installation attempts, like when changing pinion depth. This happens a lot with Toyota aftermarket gears!