New Gears Sing a Little

[Chepe]

83 K10, 31" on stock rallies, I mostly drive around town so the 2.73s weren't doing it for me. Swapped in a Motive Gear 4.10 ring & pinion set, never done that before so it was a good learning experience. Stuck with it til I got the backlash right and a decent pattern, ran it for 500 miles and just changed the fluid this weekend. (Removed the front driveshaft until I do the front.)

Two things I'd like y'all's thoughts on. One, the rear end sings on deceleration. You have to be listening for it - you know how loud squares are - but it is there and it's new since I changed the R&P. Should I be concerned?

Two, when I changed the diff fluid, there was zero backlash. As I'm writing this today it occurs to me that the ring/carrier probably can't move freely if the wheels aren't off the ground (which they weren't when I changed the fluid), and that I was just feeling the tension on the system.

There was no metal or anything else in the fluid, the whole thing looked great after 500 miles. Any thoughts/advice before I do the front? Thanks.

 

[Chepe]

I also want to say thanks to everybody on the forum, especially those of you who post often. You’ve been a big help for this first time square owner.


I bought my 83 in Raleigh two years ago. Was born with a 305 but had a goodwrench 350 put in some years ago. I live in East Tennessee and she made it across the mountain just fine (those 2.72 gears helped on the highway). As a Covid project, my sons and I pulled the 350/700r4 and put in a 5.3/4l60e that we refreshed. Lots of rewiring, new radiator, new a/c compressor and condenser, new tires, and she’s a great daily driver. I don’t think I’ve done anything to the truck without consulting with what you guys have posted in this forum, so THANKS!

 

[Keith Seymore]

When we would complain the guys from Gear & Axle would tell us: "A singing axle is a happy axle".

K

 

[Bextreme04]

I'm assuming this is a 10 bolt? I just did my 2011 K1500 suburban(still an 8.6" 10 bolt) with new bearings and ring/gear change to 4.10's and it is dead quiet. What did you set your pinion preload too? What did you set the backlash at? Did you check it at multiple locations or just 1 spot? Where you using check bearings? Did you check the pattern on both sides(coast and drive)?

You are right that you wont be able to feel anything if you have the tires on the ground and driveshaft installed. To check the backlash, you would need the driveshaft disconnected or trans in N and the tires on the ground. Place the dial gauge on the yoke and you should be able to check backlash by moving the yoke back and forth. It will read about double on the yoke what the actual backlash is at the gear.

 

[JoeR Jr]

I agree with the others in that a slight sing on decel is nothing to worry about.

On a silly side note, my Dad bought a 1973 C10 when they first because available. It was a bare-bones truck. Straight six, 3 on the tree, no power steering. From the day it was born the diff in that thing sang like crazy. It lasted until the truck rusted to pieces.

Joe

 

[Grumpy]

I'm with Bextreme. Personally, I use a Snap-On dial torque wrench with the tell-tale needle. That way I can turn the pinion nut and see what peak torque is and I also start turning the pinion nut by hand and then check the rolling torque - yes, I am CDO.

 

[Octane]

I had a racecar shop change my gears once.They said they might make a little noise.But they have everything set just right.They said that some gears,brands or whatever,are noisier than others.And that mine may actually quiet a little after some miles.They werent bad,but they did quiet down just a little bit.It was never enough for most folks to hear and pay attention too tho.With the windows up I could hear it just a bit at times.It was on light throttle acceleration thwned it for years,never a problem

 

[Chepe]

Bextreme, yep it's a 10 bolt, all new bearings, preload and backlash were within spec and the pattern and backlash were OK at multiple places. I'm going to go with Keith's fellow assembly guys and call it a happy axle. I appreciate everybody's help.

 

[Mark Ugrich]

The higher ( numerically) the gear ratio is the more they will make noise on de acceleration.You should hear the 5.86’s in my drag car on coast.