rear ratio determination trouble

[HammerWerf]

Folks,

I tried to determine the gear ratio on my C-30 83CC. The rear axle appears to be a Dana 70 with DRW. We were going to use the turn the tire, count the drive shaft revolutions.

First, we checked for a posi rear end - Oposite side wheels rotated in reverse direction, so no posi.

Next, we lined up the drive shaft for ease of the job. Moved the rear wheel in the forward direction while my son and I watched the rear yoke.

What we saw was this. The wheel turned a good 4 time around while the yoke did not move. We then tried to turn the wheel in the reverse direction, and the same thing happened.

Truck appears to operate properly when driven.

Any ideas of what is going on? And if a concern, resolutions.

Thanks,

HammerWerf

[DmaxMaverick]

Both wheels still off the ground when you did this? The opposite side wheel was turning the opposite direction (or should have been....), taking up the turns you put into the axle. If you have an open diff, you need to turn only one wheel, while the other is held stationary (or still on the ground), and the tranny in neutral, or out of park (engine off). The one wheel should turn the yoke 1/2 the gear ratio. Now, if the other wheel was stationary, then you have a problem, and a real head scratcher.

[Robyn]

These trucks "Normally"came with 4.10 gears,3.73 may have been an option but most 6.2 powered 3/4 and 1 ton rigs had 4.10
4.56 is also a possibility on a one ton but usually with a 4 speed manual box.

If you cant sort it out with spinning the wheels, pop the cover off the back and look at the ring gear. The ratio will be on the outside rim of the ring. Now this may be the number of teeth on the gears but the ratio is on there.

The oil needed changing anyway :D

Also if you get a couple helpers you can have two rotate the tires on both sides in SINC and then you can count the turns of the yoke.

Have fun

Robyn