Discussion in 'Got gears?' started by afracer, May 5, 2019.
Top or bottom? This is the coast side of used 3.42 gears in my 8.5 of my Sport Wagon.
Yeah I don't know why it did that, but its fixed now.
The first image looks better.
The 2nd or lower picture.
The first look like it would need a thicker pinion shim to go a little deeper. I am assuming this is what you did for picture 2.
The coast side is more important,but what does the drive side look like?
the second looks much better , I too would want to see the drive side. but the coast side looks very very close....if anything still a tiny touch high for my personal linings,
The drive side is basically unreadable, there were some very light scuffs on the inside as you might be able to see below. The top and bottom pics match with above. The top was with the factory .038" pinion shim, which actually measured at .037", and the bottom pic was with a .035" shim. I preferred the bottom myself.
This was my first time fully rebuilding a rear end, so I'll take any spears gladly. I set backlash to .006 - .007" and pinion preload to 18-19 inch lbs.
Since they are used gears,you may need to open up the backlash to .008-.010,favoring .010”. Leave the current pinion setting,and trying the different backlash. You might also get a better drive reading.
I should be able to give that a try as its still sitting out of the car waiting on new housing bushings to arrive. I was getting 10 different answers online trying to figure out what to set it at, and then after I was done saw that used gears should have a completely different backlash and differing opinions on how much, but I respect your experience and background and will see if I can move it out a little more.
And try to put a load on the axle or carrier so it takes a little effort to turn the pinion. That should give you a clearer pattern on the drive side. I just lightly wedge a wood block between carrier and case. If it's in the car, lightly apply parking brake. Brian likely has a good method.
I just use a pry bar and load down on the carrier or ring gear.
make sure you check your backlash in at least 3 location it sometimes will very
Thanks for the suggestions, if I can ever sneak out to the shop without spouse hassle I'll mess with it some more
Well I can tell you as long as you are taking your time as you are doing ...you will get it.
Use this as a learning experience. NO time frame will be the biggest help.
Making sure you have a carrier shim pack number will also help to keep things from throwing a headache into the deal too.
MEANING - so if the carrier preload feels good .240 on the drive and .232 on the passenger side the total shim pack is .472... SO if you always keep the carrier preload at .0472 ish .002 above or below .002 that total you should keep a consistent pattern ... whether that is .230 on drive side to 2.42 on the passenger or any combo that adds up to .472 or addition of the driver or passenger carrier shims.
Next comes getting that pattern back to what the gear was run at in someone else differential.
.010 is always my first choice in used gear backlash .... make life easier to find patterns on the wide side .
This pattern is too shallow.
The coast side on this picture was not terrible But still appears to be shallow.
so if you are at .038 open the backlash your going to be close...Add a bit more oil to the ring gear and spin it around many times and see how the pattern is swiped the oil will help movew that compound off the tooth where it hits ...too tacky of compound just confuses the pattern picture.
Your close - keep going and do not get frustrated. take a break when you need one. No one is giving points for speed here. Jim
Thanks Jim! I figured out immediately on the shim thickness and keeping the overall thickness the same to nail backlash. I was mostly worried about the pinion depth as it just didn't seem deep enough into the gears with the original .038" shim. After thinning it out it looked much better to me, but being my first time was hoping to get a better 2nd opinion. So thanks a ton! I'll get back on it this week, a speck of metal in my eye has taken me out since last Thursday, but I'm finally on the mend.
I was always told that if you are installing used gears, you must set them up exactly as they were in the other axle, even if they were set up incorrectly.That's from my GM experience and vocational training. I remember I was working on a GMC van that was under warranty and had too much backlash and another one that had a moan while coasting. GM told be in both instances not to try to change the setup with the original gears, but to replace them and set them up correctly. I guess that's just theory. I personally have never installed a used set of gears, so I can't say from experience if it will work or not.
Ok, I've got backlash at .011, is that too loose?
What does the pattern look like at .011
I forgot to take a picture but it was much better on the drive side, centered up much better. Drove it up to 70 mph and it was quiet and nice so far.
Very good. What pinion shim did you end up with so others might reference...