Worn Input Shaft??

[DavidWillClose]

I've got a knocking noise coming from the rear end, so I took off the motor to look at the input shaft. Does this look like it would be causing a knocking noise? It doesn't look great to me, but it also doesn't look bad enough to be skipping teeth. Any input is appreciated.

 

[HotRodCarts]

Is there a spline bumper in the coupler on the motor? If not or if the bumper is worn out it will cause a knocking/rattling noise. Welcome to the forum.

 

[DavidWillClose]

Thanks! Yes, there was a bumper. However, I will be replacing it. Does that shaft look okay?

 

[HotRodCarts]

It looks a little worn but I don't think it will cause any problems. Put some silicone grease on the splines before you put the motor back on. You might want to check the nuts that hold the hubs on the axles to make sure they're tight also.

 

[Patrick L]

My thought is the same about the axle/hub retainer nuts. Could you isolate the sound to either side or center ?

 

[DavidWillClose]

I've already checked all the axle/hub/wheel possibilities. This is kind of my last resort. To me, the splines don't look bad enough to be making a clunking sound, so unless the replacement of the spline bumper makes a difference (not holding my breath because that looked okay too), I'll probably have to take out the input shaft and see if the gears inside are thrashed.

 

[DavidWillClose]

Ok, now I'm just noticing in those photos (after researching input shaft replacement) that there is no seal on the input shaft bearing. Is there supposed to be? Maybe all these metal shavings (and dirt) have been getting into that bearing and that's where the clunking sound is coming from.

Crap, I really don't want to pay $120 for a new input shaft. Can I just buy the bearing (and seal)?

 

[HotRodCarts]

The shaft uses a sealed bearing.

 

[Glen Batchelor]

It looks a little worn but I don't think it will cause any problems. Put some silicone grease on the splines before you put the motor back on. You might want to check the nuts that hold the hubs on the axles to make sure they're tight also.

Silicone? Not moly?

What does the motor gear look like? If the motor gear teeth do not line up with the wear pattern on that input shaft then it will make all kinds of noise not being able to mesh fully with that much wear. How much backlash is there from hub to the input shaft before it moves? The clunking could be the diff too. If you see a lot of metal shavings up there then the diff may be toast. Pull the diff pan and drain the fluid.

The picture shows a sealed bearing, which is correct. The black plastic is the bearing carrier seal.

 

[DavidWillClose]

The motor gear looks fine to me. The motor was rebuilt not too long ago and they didn't say anything about it being worn. Very little backlash from hub to shaft. My 22-inch wheels move about an inch back and forth, so that seems pretty tight to me. Gears in the diff look fine too. The only gear I can't inspect is the one on the input shaft, but I guess I could pull that out and have a look.