Pinion bearing losing pre-load. Only after making a couple passes..... Strange. 3rd time.

Cory S

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A buddy has a 2019GT 10R80/3.55 setup. 10.10 @ 136 car. His setup keeps losing enough pinion pre-load, that it HOWLs bad after making a couple passes (1.5's) at the dragstrip. This last time, he put a brand new loaded differential in. Drove it for 3 weeks and put 700 miles on it. It was beautiful. Quiet as a mouse.

Made 2 passes last Friday, and immediately howled on the way home. WTF. Are people putting solid sleeves in these Super 8.8's or what? He's spoke with a couple rear end specialists, and they suggest running a solid sleeve, and that the factory pre-load is way too tight.

This is stumping us. There's zero reports on similar setups and even quicker cars without an issue.

 

JohnVallo

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I am interested in hearing more about this.
A few of questions:
1. Was the rear-end dissembled and verified that the collapsible spacer was the cause?
*The length of a typical collapsible spacer removed from a running setup is: 53 1/2 to 54mm long*
*A new collapsible spacer is: 55mm long, it's made from .090 thick mild steel*

2. For a howling of the rear-end to occur, the pinion preload would not only be gone, but the whole pinion would most likely be loose, (with noticeable fore-aft play). Was this the case?

3. On the new loaded diff that was installed, was the pinion nut "staked" to one of the grooves in the top of the pinion threads?
*This would ensure that the pinion nut didn't loosen. *

Appreciate,
-jv
 
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Cory S

Cory S

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I am interested in hearing more about this.
A few of questions:
1. Was the rear-end dissembled and verified that the collapsible spacer was the cause?
*The length of a typical collapsible spacer removed from a running setup is: 53 1/2 to 54mm long*
*A new collapsible spacer is: 55mm long, it's made from .090 thick mild steel*

The new differential was bolted in out of the box. His original differential was taken apart and the race/bearings already had signs of wear when it started howling. Started howling immediately after a few track passes as well. He was told today that even a solid spacer wouldn't correct this, and that possibly the quality of the bearings and hardness may have been sub par.

2. For a howling of the rear-end to occur, the pinion preload would not only be gone, but the whole pinion would most likely be loose, (with noticeable fore-aft play). Was this the case?

When he investigated it, there was no noticeable play at all in the flange. He's assembled a few hundred rear ends in his time, and has never seen this happen like this multiple times.

3. On the new loaded diff that was installed, was the pinion nut "staked" to one of the grooves in the top of the pinion threads?
*This would ensure that the pinion nut didn't loosen. *

I can't confirm this, but nothing gets by him usually. He double checks everything twice.

Appreciate,
-jv
 
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Cory S

Cory S

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Here's the answers to your questions directly from him John,

#1. The cause of the ring/pinion noise was from the front pinion bearing failure. Preload was gone.

#2. No fore/aft play, but no preload.

#3. Yes. The nut was staked and had not moved on all 3 of the failures.
 

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When it was mentioned in the first post that the friend put a "brand new loaded diff" in - are we to take that as an entirely new housing (pumpkin) from Ford Performance with the gears, etc? Or is it "new" to him but was purchased used?

Is there a possible issue with the diff housing (if using the same over and over)?

If he is installing the gears himself, is he using all new hardware (pinion nut) and not reusing the old?

If he is doing the gears himself, and if using a dial indicator to set up the rear, is he absolutely sure that tool isn't giving false readings?

Has he checked all rear sub frame mounting points as well as the mounting points for the diff to ensure nothing is flexing that would be causing any uneven deflection of the rear or axles under extreme load/launching?

Has he checked the driveshaft and the rear pinion flange - more so to make sure 1) driveshaft bolts are torqued to spec and 2) there's absolutely no issues with the rear pinion flange?


Just throwing the above out there - usually this is unheard of after a "new" diff or gear install not once, but 3x? There's another underlying issue that is not being caught or overlooked.
 


JohnVallo

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Good to know.
Not the fault of the collapsible spacer, but failure originated from front pinion bearing.
If it were me, and I still had the old bearing and cup, I would cut the cage off the cone & roller, and examine every roller for flat spots, and possibly a hardness test (Rockwell).
I've seen a lot of pinion bearings burnt-up from high preload, but they were from extended high-speed exposure. I doubt a pass on the strip would be the same. I would look more toward sudden impact (shock) from the drivetrain.

Here's hoping you get this answered.
 
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Cory S

Cory S

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Good to know.
Not the fault of the collapsible spacer, but failure originated from front pinion bearing.
If it were me, and I still had the old bearing and cup, I would cut the cage off the cone & roller, and examine every roller for flat spots, and possibly a hardness test (Rockwell).
I've seen a lot of pinion bearings burnt-up from high preload, but they were from extended high-speed exposure. I doubt a pass on the strip would be the same. I would look more toward sudden impact (shock) from the drivetrain.

Here's hoping you get this answered.
I have pictures or the bearing and race wear. The cheap Koyo bearings (very thin hardness)and factory too much preload is what the consensus says is causing this entire ordeal.
 
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Cory S

Cory S

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When it was mentioned in the first post that the friend put a "brand new loaded diff" in - are we to take that as an entirely new housing (pumpkin) from Ford Performance with the gears, etc? Or is it "new" to him but was purchased used?

Is there a possible issue with the diff housing (if using the same over and over)?

If he is installing the gears himself, is he using all new hardware (pinion nut) and not reusing the old?

If he is doing the gears himself, and if using a dial indicator to set up the rear, is he absolutely sure that tool isn't giving false readings?

Has he checked all rear sub frame mounting points as well as the mounting points for the diff to ensure nothing is flexing that would be causing any uneven deflection of the rear or axles under extreme load/launching?

Has he checked the driveshaft and the rear pinion flange - more so to make sure 1) driveshaft bolts are torqued to spec and 2) there's absolutely no issues with the rear pinion flange?


Just throwing the above out there - usually this is unheard of after a "new" diff or gear install not once, but 3x? There's another underlying issue that is not being caught or overlooked.
The third setup was a brand new loaded differential yes. He checks everything. He's been setting up rear ends for over 25 years, and never had this kind of wear/noise/failure before. They are fine on the street and fairly quiet after his setup. A couple passes at the drag strip, and the noise starts. Even with the brand new differential.
 
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Cory S

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A few pictures.

0B8B6BB3-DEA5-4673-9AF4-130D39256822.png


65B372B9-BC35-48AB-9828-A22DC2A69FDE.png


6C96E3A6-2650-437A-AC9E-07DD081030FE.png
 

Strokerswild

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My initial thought when reading the original post is a substandard pinion bearing, since it's all it can really be....

And the pics above confirm it. Go with a Timken and you'll probably never have an issue.
 
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Cory S

Cory S

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My initial thought when reading the original post is a substandard pinion bearing, since it's all it can really be....

And the pics above confirm it. Go with a Timken and you'll probably never have an issue.
That's our next move. Source better quality bearings.
 

308 Cal. Bullitt

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Solid pinion spacers usually fix symptoms you described. Good bearing are a given.
Many Timken sets are now Chinese made, yet they still have the best metallurgy of all manufacturers.

Hardness varys on crush sleeves & thru out the last 20/30+yrs, the crush strength seems to have gotten softer as a general observation.

We upgrade to Solid pinion spacers on any build around ~3600lbs+ on a drag strip,
& or, mid ~10s & quicker in 1/4.
Our own line in sand.. U gotta have 1.
Better to be cautious for the added extra cost of the solid spacer, vs crush sleeve.

Also use the best gear lube you can buy.
Torco Gear oil w/Friction Modifier is it.
85W-140
Battle tested by NHRA Pro Stock cars for yrs.
Mark Williams Ent in Colorado stocks the preferred mixture, made & bottled to their specs. They are the premier differential company on US soil.

Even if you have a Torsten Gleason style diff, the xtra clutch plate additive hurts nothing in this Torco blend from Mark that covers your clutch style posi units.

Pics below are of typical 9" spacer styles, & the best rear end lubricant for street & drag racing when not concerned w/ultra competitiveness that synthetics afford. U will get longer gear life from this lube over most others. Especially odd pressure angle gear cuts.
Mustang 8.8" ratios are all easy pressure angle cuts, btw.

May hav to make ur own solid spacer for a Super 8.8".
Bottom line. Use 1 on a drag car if you're already doing a new build or rebuild.
Crush sleeves are for stock set ups, & not a good idea when you dislike re-work.

Screenshot_20220803-171632_Chrome.jpg


Screenshot_20220803-185038_Chrome.jpg
 

Coyote Chase

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I'm getting ready to change mine also, and have also been told about the importance of a friction modifier.
 

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Solid pinion spacers usually fix symptoms you described. Good bearing are a given.
Many Timken sets are now Chinese made, yet they still have the best metallurgy of all manufacturers.

Hardness varys on crush sleeves & thru out the last 20/30+yrs, the crush strength seems to have gotten softer as a general observation.

We upgrade to Solid pinion spacers on any build around ~3600lbs+ on a drag strip,
& or, mid ~10s & quicker in 1/4.
Our own line in sand.. U gotta have 1.
Better to be cautious for the added extra cost of the solid spacer, vs crush sleeve.

Also use the best gear lube you can buy.
Torco Gear oil w/Friction Modifier is it.
85W-140
Battle tested by NHRA Pro Stock cars for yrs.
Mark Williams Ent in Colorado stocks the preferred mixture, made & bottled to their specs. They are the premier differential company on US soil.

Even if you have a Torsten Gleason style diff, the xtra clutch plate additive hurts nothing in this Torco blend from Mark that covers your clutch style posi units.

Pics below are of typical 9" spacer styles, & the best rear end lubricant for street & drag racing when not concerned w/ultra competitiveness that synthetics afford. U will get longer gear life from this lube over most others. Especially odd pressure angle gear cuts.
Mustang 8.8" ratios are all easy pressure angle cuts, btw.

May hav to make ur own solid spacer for a Super 8.8".
Bottom line. Use 1 on a drag car if you're already doing a new build or rebuild.
Crush sleeves are for stock set ups, & not a good idea when you dislike re-work.

Screenshot_20220803-171632_Chrome.jpg


Screenshot_20220803-185038_Chrome.jpg
Agree with all of the above…

For others, just do research on “Ford 8.8 crush sleeve eliminator”, there’s tons of info and it’s not “new” info either…. That option has been available for a few years now, way before the S550 came along…. It’s definitely something to consider for those who have a dedicated track car or one that sees at least 50%-75% track time.
 
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Cory S

Cory S

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Agree with all of the above…

For others, just do research on “Ford 8.8 crush sleeve eliminator”, there’s tons of info and it’s not “new” info either…. That option has been available for a few years now, way before the S550 came along…. It’s definitely something to consider for those who have a dedicated track car or one that sees at least 50%-75% track time.
The issue is, there isn’t any manufacturers that make the eliminators for the Super 8.8.
 

 
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