Dana 30 Gear Pattern Help

M

Muddy90XJ

NAXJA Forum User
Location
Lincoln, NE
I am struggling to setup a set of Motive 4.10's in my Dana 30. I have done them before in the past and have never struggled to to get a good pattern with a little patience. This is the best pattern that I can seem to get. Backlash is .008 and pinion bearing pre-load is 20 in-lbs.

Drive
image-2.jpg


Coast
image.jpg


Any help would be greatly appreciated.
 
I would get the backlash to .004 to .006" before checking the pattern again. But I agree that the pinion appears a bit too deep from the pics you posted. Try a thinner pinion depth shim, get the backlash right, then recheck your pattern.
 
spec for backlash is .006-.010, .008 is about ideal. His pinion is too deep, I'd pull .010 out which will put it around .010 for backlash and take another pattern. Oh, make sure that you put that baffle in before final assembly. I use a shim the same thickness as the baffle so I don't destroy the baffles when I do these.

Also, set preload on the pinion last, you're going to find that your ideal preload will be lost when you change depth shims. Put everything in but the preload shims and the seal, tighten it snug so that you get some drag but not overly tight that you can't turn it. Once you get a good pattern, then worry about preload. Depth, backlash, pattern, preload.

Mark
 
markw said:
spec for backlash is .006-.010, .008 is about ideal.
Click to expand...


The specs in the 99 and the 96 service manuals state .005" to .008" backlash. New gears should be set close to the min spec, my own opinion is they should be even a little tighter, say .004".

But mark has a good point, get the pinion depth right before messing with the pinion bearing preload. This will make you life much easier when you need to change the shims. Also, there should be a baffle between the inner pinion bearing cup and the housing. Make sure you didn't forget that, the missing thickness will affect your pinion depth.
 
So I took .009 out and backlash went to .011. I know backlash is a little out of spec, but this is the pattern.

Coast
photo1.jpg


Drive
photo2.jpg


Too me this pattern looked too shallow so I added .002 and ran another pattern. Backlash went to .010.

Coast
photo3.jpg


Drive
photo4.jpg


Still looks too shallow to me. What's your guys take?
 
The pinion still looks too deep. The pattern is also way too high on the face, indicating the backlash is too wide or the pinion is not deep enough. I would get the backlast tighter first, like down to about .007. I would also leave the pinion where it is and move the ring gear back .004 toward the pinion gear then pull another pattern. As was previously said, if these are new gears, you are better with a closer backlash. I would not hesitate to go as tight as .005 with the backlash.
 
MoFo said:
The pinion still looks too deep. The pattern is also way too high on the face, indicating the backlash is too wide or the pinion is not deep enough. I would get the backlast tighter first, like down to about .007. I would also leave the pinion where it is and move the ring gear back .004 toward the pinion gear then pull another pattern. As was previously said, if these are new gears, you are better with a closer backlash. I would not hesitate to go as tight as .005 with the backlash.
Click to expand...

Can you explain what makes you think it's still too deep? I'm confused when you say that but then say the pattern shows not deep enough. I guess I have just been lucky in the past and had stock shims get me close enough to dial in. This one is throwing me for a loop.
 
Just a shot in the dark but, are you using the correct carrier?
 
I did not say "It is still too deep". I tried to highlight "looks too deep" in my reply. Perhaps that was not clear enough.

The indication of too deep of a pinion is when the pattern is closer to the toe of the pinion gear tooth. than it is to the heel of the pinion gear tooth. When the pattern is closer to the face (top) of the pinion gear tooth than it is to the flank (root) of the pinion gear tooth, it can be caused by either too deep of a pinion setting, or too wide of a backlash. You know the backlash is on the sloppy side, and now that closing it up will move the pattern towand the root, that is the next logical move. If you have to make a choice, it is better to have the pattern a little lower (toward the root) than higher. This is because if you really pound the D30 hard, the housing has a tendacy to flex and force the gears apart. causing the pinion gear to climb the ring gear. Don't be surprised if this will take 5 or 6 total "adjustments". The count goes down with every gear setup you do.

Since I mentioned the D30 housings flex a lot, If you are going to beat this thing, you should consider a strong diff, cover instead of the stock sheet metal one. I really like the RuffStuff diff covers. I have one on both my XJs, with the LubeLocker gasket.
 
I had similar problems dialing in a decent pattern on my 99 XJ HP D30. Like you, I have done a few others and never had such a difficult time. I've since read others are having problems with the motives....I seriously doubt I'll buy motives again.
 
Shift about .005-.008 worth of shims from one side to the other to move the ring gear closer to pinion. That will put your backlash back into spec at around .006-.008. Then take another pattern. Too deep is where it lands between the top of the tooth and the root. However you can move the pattern across the face of the tooth (heel to toe and visa versa) by playing with backlash. A change to one effects the other, as you can see by removing depth shims.
 
I shifted shims over to get backlash to the tight side as Bryan mentioned earlier. It's now .004, but I can't seem to get the drive side away from the toe. I'm thinking the pinion is still too deep. Thoughts?

Coast
Coast.jpg


Drive
Drive.jpg
 
I have to dig up my notes but that seems in the ballpark. I think .040 was recommended starting for a D30 if you didn't have the old stack. Did you have the old stack? If so, what was it?
 
I had the old stack. I'll have to check my notes what it was. I do remember that based on the stock pinion stamp and the checking distance marked on the motive pinion I calculated .036 for starting pinion depth.
 
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