Any gear tooth pattern experts here? (Dana 30 with new 4.88s)

MangoTango

MangoTango

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I' not sure if my depth gage is junk or what but no matter how deep or shallow I set the pinion (Manufacturer spec say 2.261" from axle centerline) or how much I shim the ring side of the carrier my backlash reading has always been between 0.053" and 0.069" (which is absurd). The manufacturer spec is 0.007" of Backlash.

I set the depth gage up to be as straight up and down as I can get it without the ring gear rubbing on the back of the gage and I set the needle about mid way through its run on the tip of one of the ring gear teeth, then zeroed it out.

I finally gave up and did a tooth pattern reading, made several shim adjustments to the pinion and ring and here's where I'm at.

Compared to Jeeps Service manual tooth pattern diagram for the Dana 30 for my model year (1997), and the manufacturers tooth pattern diagram these patterns look very very close to me. Does anyone see anything that I'm missing? Any help or imput would be great at this point.

Drive Side
90815


Coast Side
90817


58671932_10219701237231929_4401468448987676672_n.jpg
 
Pinion gear looks too deep, try removing pinion shims. Also, are you removing shims from the non-ring gear side when you're adding them to the ring gear side?

EDIT: Another thing I thought of: do you have the correct carrier for the gear ratio? I believe the Dana 30 has a carrier break around the 3.73 ratio. 4.88 would need the 3.73+ carrier.
 
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What gear ratio was in It to start?
Sometimes a different carrier is needed if going from a higher gear to lower gears.
 
ElectricWizard said:
Pinion gear looks too deep, try removing pinion shims. Also, are you removing shims from the non-ring gear side when you're adding them to the ring gear side?

EDIT: Another thing I thought of: do you have the correct carrier for the gear ratio? I believe the Dana 30 has a carrier break around the 3.73 ratio. 4.88 would need the 3.73+ carrier.
Click to expand...

Thanks I can definitely take out some pinion shims. I'll start walking them back out and re running the pattern. There weren't many that came with gears

My carrier is the 3.73 + carrier, it came with 3.74 gears. From what I read the max is 4.88 on that carrier.
 
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Gollywomper said:
Found this. View attachment 90826
Click to expand...
Awesome, thanks I definitely had the 3.73 + carrier then. My stock gears were 3.74 (so says the math and the 3.74 etched into the pinion)

I'm really paranoid about this whole front axle, I think a previous owner "rebuilt it". When I took the cap bolts off the carrier literally fell out, and there was no preload that I could get my torque wrench to detect.
 
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ElectricWizard said:
Pinion gear looks too deep, try removing pinion shims. Also, are you removing shims from the non-ring gear side when you're adding them to the ring gear side?

EDIT: Another thing I thought of: do you have the correct carrier for the gear ratio? I believe the Dana 30 has a carrier break around the 3.73 ratio. 4.88 would need the 3.73+ carrier.
Click to expand...

Sorry, forgot to mention this. My first attempt at installing the carrier I took the original stack of shims and measured the stackup for each side. I then added a shim or two because the carrier literally fell out when I first took off the cap bolts. It was a snug fit, needing a dead blow hammer to get the carrier in. As I took shims away from the pinion side I added those to the ring side to keep the stack at the same amount and to keep it snuggly in the axle housing.

I did experiment with adding another shim ( my thinnest measuring 0.012") and it was a feat to get the carrier in and out, so I decided (without having a case spreader on hand) I would keep the previous set up that just needed a dead blow hammer to put it in.
 
MangoTango said:
Sorry, forgot to mention this. My first attempt at installing the carrier I took the original stack of shims and measured the stackup for each side. I then added a shim or two because the carrier literally fell out when I first took off the cap bolts. It was a snug fit, needing a dead blow hammer to get the carrier in. As I took shims away from the pinion side I added those to the ring side to keep the stack at the same amount and to keep it snuggly in the axle housing.

I did experiment with adding another shim ( my thinnest measuring 0.012") and it was a feat to get the carrier in and out, so I decided (without having a case spreader on hand) I would keep the previous set up that just needed a dead blow hammer to put it in.
Click to expand...
You'll just have to move shims to the ring gear side and also remove an equal amount from the non-ring gear side until you have a more reasonable amount of backlash. You may even need to buy more shims if you can't achieve that with the ones you got; both the kits I used for my axles had shims as thin as .003", and in the end they did end up making a difference.
 
Gollywomper said:
We’re the 3.74 gears factory for your jeep?
Click to expand...
That's a good question, it's a 97 Sahara. It did have 3.74 gears in it as I did the math and the pinion is etched or stamped with 3.74 so I know that part is right, but I made the assumption that was also the correct carrier. Is there a way to tell? Maybe a previous owner put the wrong gears on a 3.54 carrier. Is that even possible?

Maybe that's why I can't seem to get a good backlash reading
 
MangoTango said:
Is there a way to tell? Maybe a previous owner put the wrong gears on a 3.54 carrier. Is that even possible?
Click to expand...

Lay the carrier on the flattest surface you've got and measure up to the ring gear mounting face, and use the measurements in @Gollywomper post as a reference.

EDIT: Video for said measurement:

 
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ElectricWizard said:
Lay the carrier on the flattest surface you've got and measure up to the ring gear mounting face, and use the measurements in @Gollywomper post as a reference.
Click to expand...


glwood said:
Fairly sure '97 TJs had 3.55 as the lowest gear ratio. 3.73 started in '98.
Click to expand...

You two have been a big help. I'll post up the measurements in about 20 minutes. I'll be relieved if I find out its the wrong carrier. Quadratec has a Yukon 3.73 and up carrier housing for $106. which would be well worth it.

Edit - You three!
 
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Gollywomper said:
Happy that you found an answer. Sorry for the days worth of frustration. Been in your shoes on many projects before. You deserve the beer!!
Click to expand...
Lol I've been at this for a week!! But..... I've been rebuilding this Jeep since the end of September so, what a few more days? Super happy you all helped me figure it out!!
 
MangoTango said:
That's a good question, it's a 97 Sahara. It did have 3.74 gears in it as I did the math and the pinion is etched or stamped with 3.74 so I know that part is right, but I made the assumption that was also the correct carrier. Is there a way to tell? Maybe a previous owner put the wrong gears on a 3.54 carrier. Is that even possible?

Maybe that's why I can't seem to get a good backlash reading
Click to expand...

Now you know it is possible.
 
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