We have been asked about the cause of Ring Gear and Pinion noise. Assuming the gears have been cut correctly, use the following procedure.
RING GEAR AND PINION NOISE
Bevel gears are inherently noisy. A little ring gear and pinion noise is normal. However, this noise usually disappears when you add gear oil between the gears. However, the gears must also be properly engaged. Runout of the Ring Gear will cause the clearance between the Ring Gear and Pinion to change and can result in noise. Both excessive Ring Gear and Pinion clearance and zero clearance can cause noise.
STANDARD REAR AXLE
There is no adjustment for runout in a standard rear axle assembly. Runout occurs when the Ring Gear is not properly seated or the surface on which the Ring Gear is mounted is not properly seated or out of flat. Make sure all mating surfaces in the standard assembly are flat and have no burrs. If all surfaces mate perfectly there should be no ring gear runout.
RUCKSTELL REAR AXLE
There are several reasons for runout in the Ruckstell Assembly. First, like the Ford Differential, all mating surfaces in the Ruckstell assembly must be flat and burr free. Second, sometimes the P139 Bronze Thrust Plate will be bent and cause ring gear runout. To check this, use the following procedure.
1. Install the Ball Bearing on the P139 Bronze Thrust Plate. This Bearing and Thrust Plate is what the entire ring gear assembly rides on and must have no runout otherwise the Ring Gear will wobble causing the Ring gear and pinion clearance to vary.
To check, put the Ball Bearing on a flat surface and check runout of the P139 by measuring runout on the flat surface of P139 with a dial indicator. It should have zero runout. It may be necessary to correct runout by tapping on the high spots of P139 with a hammer and punch. Punch lightly as P139 will bend easily.
2. Assemble the Ruckstell assembly and place in the Ruckstell Housing sitting on the P147 Plate.
3. Insure that the assembly is properly seated and turn the assembly to insure that it turns freely and has no runout.
4. Insure that the Drive shaft assembly has no end play.
5. Assemble the Drive shaft assembly to the Rear axle housing. There should be clearance between the Ring Gear and Pinion.
6. Rotate the ring gear and insure that the pinion has clearance for 360 degrees of ring gear rotation. If you have points at which the pinion binds you still have ring gear runout.
7. Adjust ring gear and pinion clearance to approximately 0.010 in.
8. Excessive Ring Gear and Pinion clearance will produce more noise
9. Rotating the Ring Gear should produce only a little noise.
10. That noise should disappear when you add Gear Oil.
REAR AXLE ASSEMBLY
Gear mesh and clearance depend on proper Rear axle assembly. When you assemble your Differential:
1. There should be no Drive shaft end play. Since these are bevel gears, Drive shaft end play will cause the Ring Gear and pinion clearance to change.
2. The Differential assembly must have no side play inside the differential housings. Any movement of the differential assembly from left to right or otherwise will cause the Ring Gear and Pinion clearance to change.
3. Either one of these problems can cause Ring Gear and Pinion noise.
When assembling your Rear Axle, do it right and avoid these problems
I agree. I spent a ton of time sanding down the thrust washers and assembling and disassembling the rear end to get the pinion clearance just right. Only time will tell if the extra days spent on it were worth it.
Same here James.
I understood that ring gear runout is inherent with the manufacturing of the ring gear. I understood that the ring gears when cut were perfect however when heated and hardened they would distort .002 - .003. I also understood that when setting up the assembly it is set to the highest point of the inherent runout. Are gears today perfect with no runout?
Same as James also for my TT Ruckstell, sanding down the fiber thickness and assembling the unit to check clearance, sanding a little at a time.
I should add that the Ring Gear and Pinion clearance must be set before you can adjust the Differential side play. But if you do not set the differential side play to zero the Ring Gear and Pinion clearance will change. Excessive Differential side play will allow the Ring Gear and Pinion to bottom out and cause noise.