installing used gears

ok so im getting ready to order my install kit for my upcoming gear swap and would just like some input from naxja. i have a hp30 with 3.07s and i just pulled a 4.10 gearset and carrier out of a junkyard 4 banger, both the carrier and pinion bearings and races are in good shape, no scoring or excessive play.
so ive decided to just go with a minor install kit. i have a friend with experience in gearing that is going to come and help me. im just wondering if there is any set backs to using used gears in a different housing? ive heard i will end up with a lil gear whine due to the gears already being broken in..
also if there is anything bad with using the nitro install kit as opposed to yukons minor install kit? its cheaper and is more complete.

thanks


http://www.justdifferentials.com/ind...oducts_id=3291

http://www.ringpinion.com/ProductDet...px?ProdID=3042

As long as you understand going in that even when set up correctly there may still be some noise, as you already know, then go for it.

Honestly, I've never bought new gears for any of my vehicles, always something traded for or salvage yard.

No personal experience with Nitro or Yukon install kits but either should do the job.

i took a yj d30 with 4.10's into a local mechanic and he charged me $100 to swap them into my MJ D30. He wasn't an offroad guy or axle specialist or anything and he set it up with all the used bearings. only new parts were seals. the noise was noticeably less than the Yukon 4.56's in my XJ which were installed with a full kit by a professional. i'd throw them in and give it a shot. if it's really loud keep an eye on it but i think you'll be ok...

i regeared 2 diff ford 7.5 rear ends with 4.10s i got out of the junk yard, used all the bearings shims and crush clollar from the the junk yard ones, my truck went about 10 months i sold it and the guy who has had it the last 3 months i talk to sometimes says hes had no problems, still totally quiet. my brothers truck the other one has gone about 5 months on a junk yard set still not a single issue or noise

As long as you understand that you have to set them up the same way as new gears with the proper contact pattern and backlash you will be fine. Use a strong magnet inside the diff cover to catch any wear metal because the gears may have to wear in all over again. You will need to do a break in just like new gears also and change the fluid at 500 miles. I highly recommend you don't just put them in with the same shims that were used in the other vehicle. Housings vary slightly and they might be out of tolerance in a different housing.

ya i wasnt sure if it would be ok to use the same shims i know its not really recomendable but hey i gotta say with 2 successes id do it again

thanks for the input guys... i just got done lincoln locking a jy 8.8 w/410s. ive also built my own u bolt eleminators and diff cover.. last nite i ordered the nitro gear install kit, so as soon as i get my front axle geared ill have 4.10 gears, rear disks, 31 spline shafts, and a rear locker all for $200 :dunno:arty:

1990heepxj said:

ya i wasnt sure if it would be ok to use the same shims i know its not really recomendable but hey i gotta say with 2 successes id do it again

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i think what he meant was to not set it up exactly with the same shims and tolerances and leave it at that. shims are shims new or used. just dont think because it was set up with xxx shims in one housing, that it will work with the same set up in another housing. though it is a good starting point. then check with pattern grease, and go from there. good luck.

If used gears are in good condition there's no problem re-using them. The problem is that diffs are generally tricky for a lot of people and used gears wont give a good pattern as the teeth have small amount of wear and leaves the contact patch looking much different than new gears. Often times you can use the coast side teeth to view pattern, as it will be less worn.

I dont understand why you just didnt swap the whole axle. I got a front with 4.10s in it for $120 and a rear 8.8 with 4.10s for $180. Just waiting for the spring to install them. The only reason I'd see to actually install new gears instead of swapping the entire axle is if you were going to 4.56s or something. You have to take the axle off anyway so why not?

CharlieMopps said:

I dont understand why you just didnt swap the whole axle. You have to take the axle off anyway so why not?

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How do you figure? I think most people do gears in chassis- the vehicle is a far sturdier mount than most workbenches.