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Loss of bearing preload...(Fixed!!!)!

1727 Views 9 Replies 4 Participants Last post by  AZ-Trailduster
Just pulled a Dana-30 front diff apart last night for a hellatious whine at all speeds. Pulled the diff cover and ran it with all 4's up, and it clearly was coming from the pinion area. So, now I've gutted the diff, and am ready to set it back up with new pinion bearings. Thing is, the bearings/races look great, w/ zero pitting, and the pinion bearing preload before I disassembled it was next to zero. Should be 6-8 in lbs for a "used" gear set.

So, the question is, was the too low preload causing the whine, (carrier bearings look just a s good BTW) or could bearings that look great still cause a VERY loud whine. At very low speeds, I could even hear distinct click... clicks.
Any thoughts,
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Well, after playing with it a few hours, I've found the dern pinion was installed too far from the carrier from the FACTORY, and was biting into the ring gear on the drive side. That's what the clicking sound is at crawl speed.
Now, I've gotta wait til Monday to get a shop to pull the pinion bearings so I can remove a shim, jsut to find out if I'm right. There aren't any shims under the races, which I can pound in/out myself.
I've had lots of fun figuring the right pattern.....the instructions show patterns for a rear diff, and this is of course a front one. Let's hope I'm figuring right! Gotta love that Jeep quality control! (THis is a 99 Jeep GC)
Pattern's the same, but when the pics refer to drive or coast side, that must be reversed for a standard rotation diff. up front. Add to that a used set of gears, and one very green gear mechanic, and you're lookin at a LOOOONG weekend.
I finally got back to work on the diff today, getting a great pattern, backlash is good, etc. Dern problem is I can't get the crush sleeve to, of all things, well CRUSH! I've got an impact capable of 500 ft lbs. and I've got a breaker bar that's 40 in long and the dern sleeve won't budge. No interference probs, it goes together easily, and with the old sleeve installed, I get a preload, just too dern much. So I know the bearings can pull close enough together without any interference issues. I mean come on, the pinion bearing preload is a 10 minute job usually with a crush sleeve! These things are designed to crush at 300-400 ft lbs, so what gives? 3 hours to get a good pattern and 10 plus to get preload???
txs said:
they sell spacers to eliminate crush sleeves, you may have got one. If you have to much preload with the nut tight add some shim to the spacer.
Got started late today, but FINALLY!!! Went and bought 3/4" drive stuff and plumbing pipe and made a 5 ft. breaker bar. Went in in 15 mins. got great preload, and the rest of the setup went smoothly. Test drive was nice and quiet, and so now I've just completed my first set of gears.
The 500 ft lb impact just isn't enough, and the 1/2" breaker bar just flexed all the way to the floor and never turned the nut.
Now I can finally shut up about this...... ::) and move on to the next projects.
Thanks for the input BTW guys!
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