Weird R/P wear. Help Confused....

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Diablo650Hemi

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Jan 4, 2012
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Took apart my SQHD this weekend and noticed a pretty interesting wear pattern on the Ring. (This R/P only has around 10-12 runs on it)

It is ROUGH from top to bottom. NO smooth part on the Drive side at all. Sharp edge at the top and bottom of the ring. Also the bottom is chipping away.

Even where the "shining" spot is it is still rough.

Never seen anything like this. I did switch oils to a synthetic but something must be really wrong.

What can be causing all this!

Thanks for the help.
Doug
 

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That looks like a lube issue. What brand of synthetic did you change to? What were you running before?
 
I am not doubting the other guys but ive seen ring gear do that when setup too loose as well.
 
I normally set them up tight, like .002-.003 for a pulling only app. That looks like it was loose and possibly not the best lubricant for the application but I am also not an expert on lubricants.
 
That oil isn't designed for ring and pinion use more less its a universal tractor hydraulic fluid as it states on the PDF file. Petro Canada does make a good gear oil we use many of there products at work
 
Diablo650Hemi said:
Checked the backlash and we had .015-.016 on it.

Should I take a guess and say that is way to tight?

This was the oil I used (or that was recommended that i used)

http://lubricants.petro-canada.ca/resource/download.aspx?type=TechData&iproduct=1002&language=en
Click to expand...

.015 mm = .00059 inch I asume that being from canada your post is metric? If so you have less than .001" backlash, and that is too tight. I like to see .002~.003" backlash (.051-.0762 mm) clear as mudd?
 
Diablo650Hemi said:
Checked the backlash and we had .015-.016 on it.

Should I take a guess and say that is way to tight?

This was the oil I used (or that was recommended that i used)

http://lubricants.petro-canada.ca/resource/download.aspx?type=TechData&iproduct=1002&language=en
Click to expand...

We ran into a similar looking gear when running ATF in the diffs of a 6200lb superstock. The thought was lower parasitic drag and free up some HP, but it was literally being squished out between the teeth and not providing enough lubrication.

The fluid you linked to, does not seem much better than what we used and could be the reason for your issues.

I'm also not sold on synthetics for ring and pinions as we do not put "long hauls" on pulling truck gears (ie. hauling up a steep grade, overloaded, at 65mph+, for miles and miles at a time). Oil tends to break down under heat, but I'm willing to bet pulling truck gear oil does not see the same temps for the same duration as a working street truck/big rig. I'd be more worried about viscosity and anti-"squish"/shear.
 
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prostockpuller said:
.015 mm = .00059 inch I asume that being from canada your post is metric? If so you have less than .001" backlash, and that is too tight. I like to see .002~.003" backlash (.051-.0762 mm) clear as mudd?
Click to expand...

The post isn't Metric ;) Even though we are a metric country rarely anyone uses the metric system when talking about precise measurements.

So .015'" is too loose then.
 
prostockpuller said:
.015 mm = .00059 inch I asume that being from canada your post is metric? If so you have less than .001" backlash, and that is too tight. I like to see .002~.003" backlash (.051-.0762 mm) clear as mudd?
Click to expand...

No, we use inches still when setting backlash lol.
 
Diablo650Hemi said:
The post isn't Metric ;) Even though we are a metric country rarely anyone uses the metric system when talking about precise measurements.

So .015'" is too loose then.
Click to expand...

Someone correctly if I'm wrong (entirely possible), the reason for setting a tight/tighter lash is due pinion/ring gear deflection under load.

I've seen chunked teeth and irregular wear from too loose backlash, but from the pattern on the teeth, pinion depth and backlash weren't horrible and no signs of broken/cracked teeth.

While a tighter backlash will help in the future, I would be willing to bet your issues stemmed from lubrication....
 
Yes it looks like you have a lube issue. You can try switching back to regular 80w90 see what happens, but the damage might already be done. I would set it back up tight and check for more ware after a few runs.

As far as backlash. We set all r&p up tight w/ 0 backlash for dedicated pulling applications so we get maximum tooth contact and less deflection. Now it's a different story for pullers that still drive them on the road because backlash actually helps the ring and pinion run cooler at highway speeds so you don't burn up the gears from to much friction.

I noticed in the pic it looked like your ring gear is still riveted to the carrier. I would suggest drilling them out and upgrading to a bolt kit before you shear the rivets off.
 
PTPULLINCHASSIS said:
Yes it looks like you have a lube issue. You can try switching back to regular 80w90 see what happens, but the damage might already be done.
Click to expand...

X2. Once you get the surface all hosed up like that from way too thin a lube (5w-30 equivalent), even with new oil, the surface isn't going to get any better, and will probably keep shedding particles into the diff.
 
Leadfoot said:
Someone correctly if I'm wrong (entirely possible), the reason for setting a tight/tighter lash is due pinion/ring gear deflection under load.

I've seen chunked teeth and irregular wear from too loose backlash, but from the pattern on the teeth, pinion depth and backlash weren't horrible and no signs of broken/cracked teeth.

While a tighter backlash will help in the future, I would be willing to bet your issues stemmed from lubrication....
Click to expand...

Pullers set them tighter because they don't get to have a 500 mile break in period like street trucks.
 
ppumpdubs said:
That oil isn't designed for ring and pinion use more less its a universal tractor hydraulic fluid as it states on the PDF file. Petro Canada does make a good gear oil we use many of there products at work
Click to expand...

LoL where I work, we own petro canada.

But for some reason I can't pull the link to the data sheet on my phone. But someone mentioned universal hydraulic fluid. That will run you about a 10w viscosity. Not at all suitable for ring and pinion use.

Sent from my HTC Desire HD A9191 using Tapatalk 2
 
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