The Stovebolt Site Forums The Shop Area Driveline C60 2spd axle preload adjust

I find a considerable amount of slop in the diff on a '69 C60. I can rotate the drive shaft a few degrees before it engages.

I found the front cover bolts to be loose, tightened those thinking it would snug up the pinion. I can't tell much difference.

Is it possible to remove some of the slack with shims on the pinion shaft? If so, what is involved?

If it isn't vibrating or making noise, I would leave it alone. It was common to to have quite a bit of lash and I have the attitude about something like this, "If it ain't broke, don't try to fix it."

Define "quite a bit of lash".

It gets pretty annoying at a slow speed. Like taking up slack in a chain...

I never did any kind of measuring, but an end yoke can quite often be turned about an 1/8 of a turn or more. Are you talking about when you are in lower gears and let of the gas and then give it gas? If thats what it is, it is normal for larger trucks. You just have to get used to it and part of it is probably your driving habits. Driving a 2 ton is not like driving a pickup.

Your slack sounds normal, especially if you're in the "low" range with power going through the planetary gears in the carrier. Shift to high range and see if things tighten up somewhat. Ditto on the big truck/pickup differences- - - - -if you want a Cowboy Cadillac get a 1/2 ton and put late-model running gear under it!
Jerry

I'm pretty familiar with medium size trucks as we have used them at my ranch for the last 18 years or so.
I need to look again but I swear there is approximately 30 degrees of rotation at the yoke before anything make contact.
And, yea Hotrod, it is worse in low range.

Gets pretty annoying as it gets to oscillating at low speeds. Can't be good for the rest of the driveline.

It's getting stripped for paint so, I figured now would be a good time to address all these annoying issues while it's down.

There can be several areas of slight backlash which can accumulate to make for an unacceptable amount of driveshaft rotation. One of the most common problems is wear on the pivot shaft where the spider gears rotate, or in the fit of the spider gear shaft in the carrier housing. Unfortunately, excessive backlash in the ring/pinion gear fit can also become a problem, and reducing that dimension by adjusting the tooth contact will almost always cause a gear whine and accelerated gear wear. Slop in the 2-speed system is almost always a parts replacement situation, as no adjustments are possible.
Jerry