Keep twisting off output shaft on 402 rearend

Counting and dividing teeth is the most accurate. The is a way to count shaft vs axle rotation. Id have to look that up.

 

Jack up one wheel on an axle. Mark the drive yoke to the housing. Mark the tire to the ground. Rotate the tire 10 revaluations and count the driveshaft revaluations. Then figure the driveshaft to the nearest tenth.
If your drive shaft turned 20.5 revs to the ten wheel rotations it is a 4,10 ratio. The reason it may hurt your head is because the spider gears in the carrier double the speed when one wheel is stationary.
Or 20.5 divided by 10 X 2 equals 4.10.

 

There should be numbers on the pinion shaft tip where the yoke bolts on. You'll have to really clean it to see it, but it's there. mine had 10 and 39.. Divide the two numbers and that's your ratio.. (3.90)

 

But if the front rear is different the end of the pinion is inside the housing and must be dissembled to see?

 

It does not matter what is stamped on housing. Do not ever trust these numbers. Check them for yourself. Many years of installing remams. I always check. Ive seen factory fup. Remember they hire the best and most experienced employees for these positions. Lol

 

Btw cant count tire rotation. Different size or brand mean nothan. Axle rotation vs. Yoke is were ratio is calculated. Nuthan to do with tire or rim.

 

Last time I checked the axle is connected to the rim which is connected to the tire.

 

Just spin it 10 times and count the yoke rotations. Then do the same on the other diff. If they are different you found the problem.

 

If they didn't see it and actually test it, they don't know what it was.