New Gearset High Pitched Squeal

[cebra]

I put a new R&P (3.42 Excel by Richmond Gears) in and a Auburn Gears Positraction along with a Richmond Gears Install Kit. We measured the backlash many times at .008 and the pattern on the gears we thought matched the picture in the instructions on both sides...maybe slightly toward the outside (heel?) of the ring gear (see pics). The turning force of the pintion once it was installed/sleeve crushed was in spec at 25 inch lbs. At 40 mph I develop a crazy loud ear piercing high speed squeal and it gets worse with speed. We jacked the truck up and it was very noticeable and only changed slightly when let off the accelerator (seemed to be more speed induced). Any thoughts on this would help? Do I need to let the gears break in more?

[HO455]

What other new parts were installed?
How much torque does it take to turn the input yoke?

[cebra]

Originally Posted by HO455

What other new parts were installed?
How much torque does it take to turn the input yoke?

25 in lbs on the input yoke.
Other parts installed were axle seals/bearings and a chrome diff cover.

[AussieinNC]

Stupid question....you did fill it with gear lube after all this work?

[KQQL IT]

What's the pattern look like now?

[kwmech]

What does the pattern look like on the drive side? From the coast, pinion looks a little deep

[cebra]

Originally Posted by kwmech

What does the pattern look like on the drive side? From the coast, pinion looks a little deep

It is slightly further in (toward the center of the ring gear), by pinion being deep, do you mean the pattern on the ring gear is a bit far to the outside of the gear? I was slightly concerned it may be a smidge vs the generic picture I was lining up against.

[cebra]

Originally Posted by KQQL IT

What's the pattern look like now?

I would suppose the same, have not broke the case and want to get an idea of what may cause a high pitch squeal at speed before I do. I heard the Richmond Excel gears are loud but this you could probably hear for miles so it seems way excessive.

[Ziegelsteinfaust]

If your pinion depth is wrong, and that will make a load high pitched sound.

Another possibility is you got cheaper gears. I called 3 different manufacturers of these things, and they all said the same story. Gear whine in cheaper sets is very common, and the high end sets something is wrong.

The difference is not in the gear forging, but in the quality of the machining as the final process. My 69 Camaro will have gear whine in all likelyhood, but I won't hear it over the 500hp loud exhaust. Problem solved

So all is good.

[HO455]

Originally Posted by cebra

25 in lbs on the input yoke.
Other parts installed were axle seals/bearings and a chrome diff cover.

Actually I was asking how hard is it to rotate the pinion with the axle off the ground. I am assuming that you are not hearing a gear whine but something much worse. It could be that the new pinion gear is trying to eat it's way out of the carrier bearing. Thus my question about how hard is it to rotate the pinion since the test drive.
Sorry I didn't pose the question very well.

[cebra]

Originally Posted by HO455

Actually I was asking how hard is it to rotate the pinion with the axle off the ground. I am assuming that you are not hearing a gear whine but something much worse. It could be that the new pinion gear is trying to eat it's way out of the carrier bearing. Thus my question about how hard is it to rotate the pinion since the test drive.
Sorry I didn't pose the question very well.

I am not sure how to measure that with the driveshaft on.

[cebra]

Are you thinking the pinion is too tight and eating into the pinion bearing (rather than carrier bearing) or the one directly behind the pinion gear if I am classifying it wrong? We did not go by crush force but rather crushed and spun to measure in lbs on the yoke further and further until it was 25 in lbs.

[RustyPile]

Just going by the single pic you posted, the pinion gear is set too deep (too near the axle centerline).. I think the pinion needs to be moved about .002" or so away from the axle centerline.

Your picture shows the pattern on the coast side.. We need to see both coast side and drive side, so drain the oil, clean the oil residue from the gear teeth, and apply the checking dye to both sides of the ring gear teeth in 4 places.. Remove the axles for this procedure.. Also, you can't check the pinion preload with the axles installed..

[kwmech]

If the marking is further in, then pinion is way too deep. Pattern needs to be as close to center as you can get it. Looks like-- seeing the white marking paste-- that the gears were lapped during polishing. Shoot for that marking. I'm guessing to remove about 6-8 thou and reset the backlash, take another pattern check and post it up.

[cebra]

Too deep I assume means remove shims from the pinion to move it further into the case which would move the lap out further from the middle of the ring gear correct? I have a .003" shim on the pinion so I can only move it .003" further into the case by removing this shim. Am I understanding correctly?

[kwmech]

Yes, but you may have to remove more than 3. But check it anyway

[cebra]

Originally Posted by kwmech

Yes, but you may have to remove more than 3. But check it anyway

I am not sure how to remove more than .003 if that is the only shim I have in it? Here are better pics of the gear pattern.

[cebra]

and 1 more

[Ziegelsteinfaust]

I am not a expert, but my gear paste looked like yours. When I took it to a expert to vericate my work. It ended up my lash was also tight.

He reset it, and said I was close. Not bad for a first try.

So I will try again in a few months, and hopefully learned from my mistakes.

[HO455]

Originally Posted by cebra

I am not sure how to measure that with the driveshaft on.

I would just turn it by hand and see if it takes more effort to turn the yoke than one would expect. There could have been a piece of debris that has ended up in a bearing or you got a bad bearing and this is causing the noise.
I would do a spin check of the wheels too.
This is all predicated on the fact you said it was a "crazy loud ear piercing high speed squeal ". Which is not what I would expect to hear from a gear set that was not perfectly set up. An annoying whine yes. A crazy loud ear piercing high speed squeal not so much.

[kwmech]

Was that after the 3 removal? back lash?

[cebra]

Originally Posted by kwmech

Was that after the 3 removal? back lash?

No that is with the .003 before disassembly. Backlash is .008, myself and the shop owner measured it 5 or 6 times before and after driving it around.

[kwmech]

That pattern there looks really good. What oil did you guys put in it?

[cebra]

Originally Posted by kwmech

That pattern there looks really good. What oil did you guys put in it?

I thought it did too, Richmond says not so much...we are too far out on the ring gear and that is what is causing the squeal. The guy who helped with this (shopowner) has done dozens of rear ends and said he never heard the noise we encountered and has not seen a gearset that is that picky about exact contact (Richmond says to move the pinion .004" out, add a .004" shim). We used non-synthetic 80w90 with friction additive for the LSD.

[cebra]

The plan is to blow it all pack apart, add a .004" shim to the pinion, reset the carrier to get .008" backlash and redo the pattern to send to Richmond. I have been doing some research and quite a few people say the Excel Gears by Richmond are quite loud in general. With that said, the noise this thing made at 40mph is the loudest high pitch squeal I can ever recall hearing...like a bad wind whistle on a leaky door x 1000.