diff noise??

[amaurer]

I have a noise coming from the rear-ish of my cruiser (full float). Its audible over 35mph, and its a sorta drone, increasing in pitch with road speed.

It could be tire noise, but it could also be diff noise. I've never heard diff noise before, can anyone describe it?

If it IS diff noise, what needs to be done? Is that the sound of the diff destroying itself or can I just live with it?

 

[inkpot]

Howdy! Could be just a tired ujoint. Could be tired or dry pinion bearings. Have you check your fluids lately?? John

 

[amaurer]

Fluids are something I've been meaning to get to. I have a bad pinion seal in the rear, so I know I've lost some to that. When I replace the seal this weekend I was going to change and refill.

Some more detail on the noise: it occurs only when accelerating, not when coasting. It sounds kinda like driving on a grated bridge or grooved road, but very smooth and regular (not grinding or anything).

How do I check the U joints? I just had the shafts disconnected when I did the clutch, I didn't notice anythign alarming.

 

[Herb]

STOP DRIVING! I had the same thing and my pinion was being sucked into the diff because the stake nut on the pinion was loose. It is a simple fix if you don't drive it until it shreds.

This may not be your issue, but it is surely worth dropping the driveshaft and seeing if that stake nut is loose.

Check it out, TODAY!!!!!

 

[Weedhopper]

I would stop driving it too. I had a diff in a different vehicle that started to whine, then it blew up... as in case and all. It won't break if it's parked.

 

[steverb]

block the front wheels put in neutral no e brake crawl under truck grab the drive shaft and if you can move it side to side or up and down means for worn part. replace what moves

 

[amaurer]

STOP DRIVING! I had the same thing and my pinion was being sucked into the diff because the stake nut on the pinion was loose. It is a simple fix if you don't drive it until it shreds.

This may not be your issue, but it is surely worth dropping the driveshaft and seeing if that stake nut is loose.

Check it out, TODAY!!!!!

Wow, could this be Case #95098447983 of ih8mud aving a noob lots of time and trouble??

I took the driveshaft off and wiggled the flange. There was a bit of motion and I was thinking "oh s***, i can't rebuild a third, god damn it!!". Closer inspection reveals that only the flange moves, the shfta was solid.

Turns out, the stake nut is loose!!!

Thanks for the warning Herb. I ground the staking off and the nut is easily rocked back and forth by hand. I've got to find a 30mm socket to break the rest of the staking away and then replace the pinion seal, but you saved me a bunch of s***!

 

[amaurer]

Ok, put everything back together, and replaced the pinion seal (although we'll see if it holds, I may have deformed it a bit when I was banging it in )

Sadly, the noise is still there. Things might be a little quieter, I really can't tell.

I'm very glad I fixed the loose pinion, but it looks like it wasn't to blame. There is no play in the pinion, the bearings seem fine.

Could the quality/quantity of my gear oil be to blame? I'm running a 90W chocolate malt right now... see pic... ?

 

[1973Guppie]

ummmmm, yes, that does not look right.....

 

[mjrsfj40]

Looks like you got a wee bit of water in the differential along with your gear oil. You will definitely want to make a change there.

As to the noise, it would appear the drive side of the ring gear has developed some wear. This could have come as a result of the pinion gear loosening and wearing a new pattern on the ring gear. Bad news, as the noise will likely not go away.

The cheap fix (and not a guarantee) would be to refill it with 140W gear oil and live with the noise. The best fix is to replace the ring and pinion - not cheap, but best in the long run.

 

[amaurer]

what will the heavier oil achieve? drawbacks?

Thankfully the noise doesn't bother me, if it can run indefinitely then I will do so. If its a timebomb then I'd like to know that now...

 

[Pin_Head]

So what is the pinion preload after you torqued the pinion nut? How did the preload shims look? If the bearings are too tight, it won't last long.

 

[amaurer]

So what is the pinion preload after you torqued the pinion nut? How did the preload shims look? If the bearings are too tight, it won't last long.

I didn't inspect the shims, I just bolted everything back up... this was the plan all along, although in retrospect the loose pinion nut might have been a clue that I should check everything...

in any case, I didn't know I could check the preload while the third is installed. am i just to use the backlash in the geartrain to take the measurement? what am I looking for, like 5in-lbs or something?

 

[Herb]

I'm really glad you caught that pinion nut before things got worse. That noise may quiet down after you take the water out of your diff and put some good gear oil in there, then drive it for a while.

The other option (which is also kinda cheap) is to replace the third now..then use this "noisy" one as a spare. Maybe try to find a front diff donor (they are interchangeable) that doesn't have as many working miles as a rear.

 

[Pin_Head]

Ideally, you would check the preload before and after torqueing the nut and if the preload increases by more than about 2 ft pounds then it is too tight. Practically, you can guess if it is to tight if it is hard to turn even with the axles in or if the diff housing gets too hot to hold your hand on after driving it for a few miles at 60 MPH. It is not unusual for the shims to get ground down when the nut loosens up so that you need to reset the preload properly.

 

[amaurer]

I'm really glad you caught that pinion nut before things got worse. That noise may quiet down after you take the water out of your diff and put some good gear oil in there, then drive it for a while.

The other option (which is also kinda cheap) is to replace the third now..then use this "noisy" one as a spare. Maybe try to find a front diff donor (they are interchangeable) that doesn't have as many working miles as a rear.

I have manual locking hubs up front, so one would assume that the front doesn't have very many "miles" on it... maybe I could pull a switcherooo? One caveat, I find the yoke on the front is a bit scored near the seal surface. I popped ina new seal anyway to see if it works, but if I do the swap I'd probably keep the scored yoke up front.

Anyway, how hard is swapping a third? I have a full float rear, I think I recall reading that makes it easier?

 

[KOOTENAY KRUZER]

By swapping front to rear, the "new" front will be wearing on the unused new condition backsides of the gear teeth and the "new" rear will be wearing on the unused new condition front sides of the gear teeth. I wonder how many of us (me for one) have at sometime bought a new third when maybe we could have solved the problem by swapping front to rear?

A ff rear makes it easier because you don't have to jack up the vehicle and pull the wheels off, and there is no "c" clip holding the axles into the diff.

 

[Herb]

Anyway, how hard is swapping a third? I have a full float rear, I think I recall reading that makes it easier?

My local club helped me out....and we did axle bearings and the third, it took about 1/2 a day. It really took us a full day...but that is because I purchased the wrong bearings. There is a video of the procedure on Youtube. Just type in CLCC tech day.....enjoy!

 

[Herb]

Here is the link for Youtube.....
YouTube - CLCC part 1 of 3

There are three parts......

 

[amaurer]

By swapping front to rear, the "new" front will be wearing on the unused new condition backsides of the gear teeth and the "new" rear will be wearing on the unused new condition front sides of the gear teeth. I wonder how many of us (me for one) have at sometime bought a new third when maybe we could have solved the problem by swapping front to rear?

the more I think about this, I'm skeptical... these are helical gears, so two sides of each tooth are not identical one if convex and one is concave. I would imagine the fine folks at Toyota intended for only one of those sides to see use.... so are the front and rear thirds actually different?

Thanks for the video Herb!! If I can get some clarification on the front/rear swap issue I just brought up, I'll decide how to handle this.

(FYI, filled with 85W-140, noise is still there. It doesn't bug me so for now I will do nothing.)