High pinion Dana 30 contact pattern

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03sahara

TJ Enthusiast
Joined
Apr 29, 2020
Messages
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Location
Québec
Hello everyone I’m in the process of changing the gears on my Dana 30 hp to swap into my TJ. I have a quick question this is my first regear and would like to ask if my contact pattern looks good. This is a used gear set so I realize the pattern isn’t going to be perfect. These are also my set up bearings so it will probably change a bit when I press them on. Thanks in advance.

Ethan
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wait for others to chime in but to me it looks deep from the dark witness in the bottom of the 2nd pic.
 
IMHO, just my two cents..

Used gears are a PITA to set up because the surface is work hardened the first time they are run. So in order to get them set up properly, you need run the pattern before they are uninstalled and set it up with the same pattern if that makes sense. You can make a good pattern like you did here (albeit just a tad bit deep) but it will wear differently if not on the original contact pattern.
 
I realize it’s not ideal but I got them for free and my rear diff has a missing pinion tooth so I had to put the money towards the rear end with money being tight lately. So do you guys think that I should back the pinion out a tad and recheck pattern?
 
b4 i did that i'd clean that paste up, mix another batch with a couple drops of gear oil. and get a good hold on ring gear with pressure while you crank that pinion around. see if it cleans up the patches. lotta smear going on there.
 
With no other info I wouldn't hesitate to run that although these pics make it look just a bit shallow.
 
ya huge change just from the paste n pressure. definitely doesn't look to deep now.
hosejockey has more exp. than me.
 
Yeah that cleaning and oil worked pretty good thanks for the tip. I guess I’m gonna press all the new bearings on and test it again. And for other info what do you need? Backlash is at .006-.008 the pinion preload i would like to increase it just a bit though.
 
In the 2003 tj service it has a reference for preload of pinion and carrier
DIFFERENTIAL BEARING PRELOAD CHECK
The final check on the differential assembly before installing the axles is torque to rotate pinion and dif-
ferential combined. This will verify the correct differential bearing preload.
Torque to rotate the differential and pinion should be the torque to rotate the pinion plus 0.79-1.24 N·m
(7-11 in. lbs.) I cant find this in the 1998 XJ manual would you think it’s close to the same. I have to use a dead blow to get my carrier in.
 
So I pressed all my new bearings on and this is the pattern I got. Is it too close to the crown does this require a deeper pinion? If the pinion needs to go deeper what thickness shim do you suggest?

Thanks,

Ethan
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Too shallow. Move in big increments so you can see the change and then fine tune it. I'd add .010. Those pics are really good!
 
Is it run able like this I’m out of shims now and if I pull the carrier bearings off again it will damage them. If it’s no good I order some shims if I have to.
 
Yeah I would run that if out of shims. Worst case scenario is you'll be doing this again soon! You now have what we call "experience" lol.
 
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