New Gearset High Pitched Squeal
 

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?

Re: New Gearset High Pitched Squeal
 

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

Re: New Gearset High Pitched Squeal
 

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

Re: New Gearset High Pitched Squeal
 

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

:devil::devil::devil:

Re: New Gearset High Pitched Squeal
 

What's the pattern look like now?

Re: New Gearset High Pitched Squeal
 

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

Re: New Gearset High Pitched Squeal
 

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.

Re: New Gearset High Pitched Squeal
 

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.

Re: New Gearset High Pitched Squeal
 

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.

Re: New Gearset High Pitched Squeal
 

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.

Re: New Gearset High Pitched Squeal
 

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

Re: New Gearset High Pitched Squeal
 

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.

Re: New Gearset High Pitched Squeal
 

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..

Re: New Gearset High Pitched Squeal
 

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.

Re: New Gearset High Pitched Squeal
 

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?

Re: New Gearset High Pitched Squeal
 

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

Re: New Gearset High Pitched Squeal
 

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.

Re: New Gearset High Pitched Squeal
 

and 1 more

Re: New Gearset High Pitched Squeal
 

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.

Re: New Gearset High Pitched Squeal
 

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.

Re: New Gearset High Pitched Squeal
 

Was that after the 3 removal? back lash?

Re: New Gearset High Pitched Squeal
 

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.

Re: New Gearset High Pitched Squeal
 

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

Re: New Gearset High Pitched Squeal
 

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.

Re: New Gearset High Pitched Squeal
 

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.

Re: New Gearset High Pitched Squeal
 

Your current pattern looks acceptable and moving it a little i dont think is going to make a real difference. I cant think of what else might cause the noise though.

Re: New Gearset High Pitched Squeal
 

On the coast side of the last picture you can see the smooth spot worn into the gears from driving it, do you see that on the other side? Are you sure the backlash was correct and the same all the way around? No Runout? Pattern looks possibly a tad deep into the gear root.

Re: New Gearset High Pitched Squeal
 

The same all the way around? Does that mean to measure on a couple different places on the ring gear? We just measure it where it was at. Here are the pics after adding a .004" shim, Richmond says it looks good as far as the pattern goes but maybe it is a little deep (backlash too tight)?

Re: New Gearset High Pitched Squeal
 

Yes check backlash at 4 spots, checking for runout.
Pattern does look good, as far as depth to root, your prob best judge in person, helps sometimes to clean marking compound from root with a q-tip to see if centered.

Re: New Gearset High Pitched Squeal
 

Just looked at pattern again on page 1, current pattern is much better. I would run it if backlash is good and no runout.

Re: New Gearset High Pitched Squeal
 

Last pattern we sent to Richmond (same shim as the last pics I posted just all bolted up). When I saw this, I didn't like the pattern as it looks too far to the outside of the ring gear vs the crappy thumb size pattern pic in the manual but Richmond said yup that is it. Drove it down the road, squeals like 1 million shrieking children...actually sounds more like a very loud, very high pitched whistle. I mean very loud as in probably the loudest single noise I have ever heard in my life. One takeaway is that the squeal has seemed to move from starting at 40mph to more like 55mph so that may change something. The shop thinks it is a bad gearset as they are up in arms, I am considering swallowing my now ~$2K I have in this and put my 3.07/GM Carrier back in, whatever work I have to do I will need to do myself now since the shop has chalked it up to a parts issue and I am 50/50 on that. In hindsight, I should have just bought a new rearend and dropped that in myself. Specs below for any rearend experts to comment:

Pinion shim - .034
Backlash - .0085
Pinion Preload - 25 in lbs

Re: New Gearset High Pitched Squeal
 

The shop put a stethoscope on the rearend and seems to think the pinion nut is too tight and the squeal is coming from the pinion bearings being sandwiched. They said they found somewhere that the 20-25 in lbs spec in the GM manual may be incorrect for the new bearing set (which had no torque spec) and are going to set it at ~12...anyone else run into this on a new gear set?

Re: New Gearset High Pitched Squeal
 

Gm shop manual has a spec for bearing preload, new and used, i haven't looked it up in a while but its there.

Too much preload is not usually a problem, i have overshot the preload many times and they run out fine, the bearings are relatively large and in a gear oil bath at all times so they can take a lot of load.
High pitched squeal now that i think about it sounds like stamped steel rubbing on Something, could the oil slinger on the pinion flange be rubbing on something?

I also had a driveshaft carrier bearing oil slinger get loose and make a squealing sound once.

Re: New Gearset High Pitched Squeal
 

What other work was done at the same time?
Driveshaft?
axle shafts?
5 lug conversion?
Anything?

How about this...remove the axle shafts, spin it up without them
Remove the carrier and spin it up again
Try to isolate the noise to the ring and pinion or bearings

Re: New Gearset High Pitched Squeal
 

We did replace the axle seals/bearings the first go around and one axle was pretty worn so we replaced that between the 2 times where it squealed (squealed before and after replacing the axle). I think they are already blowing it apart again and I don't have a warm fuzzy feeling about backing off the preload to 12-15 in lbs. The 1971 GM manual says it needs to be 20-25 and I have heard that it will end up in the 12-15ish range after break in.

Re: New Gearset High Pitched Squeal
 

exactly right on the preload before and after...
Maybe they are saying pinion was set to spec but they know its actually way tighter and are now finally going to back it off....

Backing it off is a lot of work and requires a new crush sleeve, probably why they didn't so it before. Starting the crush is a real bear in terms of force and tool set up.

Re: New Gearset High Pitched Squeal
 

If you do decide to put another set of gears into it look at Motive Gears. I went down the Richmond road and will never do it again. I have a Motive set in my GMC and they have been great.


Smitty

Re: New Gearset High Pitched Squeal
 

Thanks, they backed off the pinion to 6 in lbs to purposely set it super light and no change in sound so I called Summit and they are sending me a Motive and taking the Richmond back. The shop has to redo the crush sleeve to get it to 20 in lbs again so minimal work to change the gears out.

Re: New Gearset High Pitched Squeal
 

Been using Richmond gear sets for 30+ years with not a single issue. Not saying there can't be a bad apple in the bunch, but... I don't think I've been lucky either. :)

Gary

Re: New Gearset High Pitched Squeal
 

Have you used Excel by Richmond by chance, in hindsight I have not read very good things about them and there is a massive price discrepancy between those and regular Richmond gears so they may just be of lower quality? The guy doing the work has done a lot of gear sets on various vehicles (more of a FCA than GM guy though) and as much as I thought he/we set it up wrong, we have had it in and out with various changes 4 times now as neither of us wanted to believe it was a parts issue. Once Richmond confirmed the pattern and backlash through pics and we did the pinion load change for good measure I have given up and chalked it up to a parts issue. When we called Richmond they said "gears make noise, send it back to Summit" so that is what I am doing, the noise is horrific is all I can explain it. Not a whine, not a clang, ear piercing whistle noise that sounds like it may be the noise that busts glass. I can feel it through my entire body sitting in the seat at 60mph. Now if the Motive makes the same noise...well after I puke a bit I will replace the pinion bearings a 3rd time and the carriers a 2nd and say the Richmond gears were fine. Will update by Monday on status of new gears.