I think this is the best option.
Solid differential spacer results
- Thread starter Softballer77
- Start date
I think this is the best option.
I used these carrier shims from Summit, allows small changes and the ability to assemble.
YGA-55002
Carrier Shims, Steel, Ford 8.8 in., GM, 8.0, 8.6, 8.75, 8.875 in., Kit
(Mfr. #: SK SS12)
Question that I have is how do you remove the rear pinion bearing w/o tearing it apart? Those darn things are $$.
NIXDSG
YGA-55002
Carrier Shims, Steel, Ford 8.8 in., GM, 8.0, 8.6, 8.75, 8.875 in., Kit
(Mfr. #: SK SS12)
Question that I have is how do you remove the rear pinion bearing w/o tearing it apart? Those darn things are $$.
NIXDSG
Last edited:
Check with Randy's ring and pinion. they sell a clam shell like tool that clamps under the bearing and uses something like a puller thread to walk it off. Cost may be more than you want to spend for a one time use. The pinion bearing should be less than $25. Find a bearing supplier and cross ref the number. Do not forget the shim under the bearing.
Have there been any gear whine issues with the stock 3.31s?
Tom
Tom
I've read of a few.
The shop that swapped my 3.31s to 4.10s claimed they heard slight whine with the stock setup, but I didn't recall hearing it myself though.
What is everyone's opinion on a good girdled cover's impact on whether or not a rear gear will whine? The more I'm thinking about it, the more I'm starting to lean that way.
As talking about my earlier Mustang that never whined with Motive 4.10s and countless slick launches, I DID have a girdled cover on it. I wonder if that really played a part in that rear never whining...
It has to be stronger with the bearing cap bolts/studs extending into another rigid mount point. The girdle cover will address the carrier bearings trying to be pushed apart, but nothing for the pinion. Staying with the 8.8 the solid spacer and the pinion nut down tight is all its got.
Well, maybe i'll refrain from spending the extra money if it doesn't really make that big of a difference.
My 3.31s had a slight whine at highway speed. The initial install on the 3.73s was quieter than stock but that didnt last long.
Your best bet is to use all of the upgrades, that will minimize the chance of failure or noise issues. Having a cast aluminum cover supporting the carrier bearing caps certainly never hurt.
I'm guessing you are measuring pinion preload with an lb-in needle style torque wrench? Feeling the turning torque by hand is a good ballpark, but certainly not all that accurate. I'd use the solid pinion spacer and then set pinion reload to the high end of the specification. The pinion bearing preload spec for your car is 16-29 lb-in, I'd go toward the higher end of that to minimize movement of the pinion when under a heavy load.
U
Unfortunately many here haven't been paying attention on these 8.8 build/gear whine threads.
Yes the stock gears whine as do any other gear, it is not ratio specific or maker, although I prefer FRPP gears.
The problem is axle assembly flex.
My stock 3.31s whined, dealer replacement FRPP 4.10s whined, built 8.8 with Revan micro polished FRPP 3.73s whined.
All were basically silent UNTIL THEY WERE LAUNCHED AT THE TRACK, even the dealer installed 4.10s made noise after street testing the drag radials.
So, the common denominator is these are heavy cars with high torque that flex the rear end.
My first 8.8 build had a solid spacer, welded axle tubes, girdled cover but didn't have bracing at the chassis builders advice (3000-3400# auto race cars are different than 4000# stick GT500s).
After even that developed whine and I realized I liked 4.10s better, he rebuilt it with substantial front AND rear bracing, as well as heating the housing to simulate flex and torquing pinion to max specs.
Now, I blew the oil pump gears testing before putting the braced 8.8 to the test but if that fails, it's 9" time as it has 3 areas of support for the pinion vs the 8.8s one.
See Team Z Motorsports s197 chassis brace for weld in (ask for front and rear like they built on my GT500) or Swarr bar for bolt in.
All my gears were silent before aggressive launching, and after 4 gear sets, my best advice is to brace and girdle.
-J
Unfortunately many here haven't been paying attention on these 8.8 build/gear whine threads.
Yes the stock gears whine as do any other gear, it is not ratio specific or maker, although I prefer FRPP gears.
The problem is axle assembly flex.
My stock 3.31s whined, dealer replacement FRPP 4.10s whined, built 8.8 with Revan micro polished FRPP 3.73s whined.
All were basically silent UNTIL THEY WERE LAUNCHED AT THE TRACK, even the dealer installed 4.10s made noise after street testing the drag radials.
So, the common denominator is these are heavy cars with high torque that flex the rear end.
My first 8.8 build had a solid spacer, welded axle tubes, girdled cover but didn't have bracing at the chassis builders advice (3000-3400# auto race cars are different than 4000# stick GT500s).
After even that developed whine and I realized I liked 4.10s better, he rebuilt it with substantial front AND rear bracing, as well as heating the housing to simulate flex and torquing pinion to max specs.
Now, I blew the oil pump gears testing before putting the braced 8.8 to the test but if that fails, it's 9" time as it has 3 areas of support for the pinion vs the 8.8s one.
See Team Z Motorsports s197 chassis brace for weld in (ask for front and rear like they built on my GT500) or Swarr bar for bolt in.
All my gears were silent before aggressive launching, and after 4 gear sets, my best advice is to brace and girdle.
-J
Last edited:
I don't know of anyone's that whined as bad as when they replaced the stock gears with aftermarket ones. Sure, a tad, but if Ford had problems with people not being able to carry a conversation over the whine (my situation), there would be a mass recall. And there have been tons of launches on 3.31s, me included. Axle assembly flex was just as bad before my gears were swapped than later. To me, there has to be something missing or differently done/happening between the stock assembly and an aftermarket change.
It's too bad you weren't able to test the limits of your new setup before the oil pump gear went. I would have been very interested.
It's too bad you weren't able to test the limits of your new setup before the oil pump gear went. I would have been very interested.
I know it's frustrating but a couple things you're overlooking.
1) Ford does know gear/diff whine is a problem on the Mustang, it's just that most don't race like we do and the ones that do and get whine are covered no questions, mine were and a member here has had like 3 full replacement axles assemblies under warranty.
2) if replaced correctly, there will be know difference in swapped 4.10s than stock 3.31s. In your case, I'd be asking the installer but
3) by definition, the gear swap increases mechanical advantage and produces more torque and potential flex on the assembly at launch.
I'm very confident, the many 3.73 SS at 850hp that have a fuse (standard summer rubber) could be driven their whole life to shows and never whine.
I'm shocked with all that performance use that your stock 3.31s didn't whine. I'm assuming they did to some degree.
Just trust me and learn from the money I've spent, throw it all at the 8.8" if you're going to race or have a sticky tire---girdle with studs, welded tubes, bracing, etc.
If someone figures out the magic formula, please enlighten us, as the axle currently under my car has the most bracing you can reasonably do for a street/strip car with 3" pipes, and all the mods above.
Good luck.
-J
1) Ford does know gear/diff whine is a problem on the Mustang, it's just that most don't race like we do and the ones that do and get whine are covered no questions, mine were and a member here has had like 3 full replacement axles assemblies under warranty.
2) if replaced correctly, there will be know difference in swapped 4.10s than stock 3.31s. In your case, I'd be asking the installer but
3) by definition, the gear swap increases mechanical advantage and produces more torque and potential flex on the assembly at launch.
I'm very confident, the many 3.73 SS at 850hp that have a fuse (standard summer rubber) could be driven their whole life to shows and never whine.
I'm shocked with all that performance use that your stock 3.31s didn't whine. I'm assuming they did to some degree.
Just trust me and learn from the money I've spent, throw it all at the 8.8" if you're going to race or have a sticky tire---girdle with studs, welded tubes, bracing, etc.
If someone figures out the magic formula, please enlighten us, as the axle currently under my car has the most bracing you can reasonably do for a street/strip car with 3" pipes, and all the mods above.
Good luck.
-J
I too have a 3.73 that has gotten louder over time. Before the swap my 3.31's were getting louder so I didn't see much risk. Car now has 2200 miles on it (swap at about 1500). My car is a base so it has the standard locking diff. which makes it unusual in this crowd. I do launch on a 15" Mickey, but only around 8 passes total. I am beginning to get suspicious of the drive shaft in our cars as a source of the noise. Everything else is nearly identical to the '12 models which seem to take the 3.73 with much less whine. CF will have a different resonance than aluminum or the ungodly steel 2 piece the earlier cars had. Could be nothing, but it's my prime suspect at the moment. I have zero faith in the solid crush sleeve solution. How would you crush the sleeve with a hard launch? The large pinion bearing and race take the thrust load, so how does that effect the sleeve? The only force on the sleeve is the bearing preload and a slight increase on deceleration while engine breaking. Am I missing something here?
I think you are making an assumption the crush sleeve or solid preload spacer is the sole culprit of gear whine.
I agree, it is probably the weakest link in maintaining set preload, backlash and tooth pattern, but it is not the only issue.
Mine whines with the FRPP cover on.
I have seen many posts on gear whine. I thought I had seen a FEW 3.31 issues. However, it seems just about everyone going 3.73 or 4.10 ends up whining, some rather quickly.
Could it be due to the smaller pinion you end up with when going with lower gears? The twist on the pinion gear would be tighter and have less gear surface area to contact the ring gear. This may be part of the reason Ford decided to go with 3.31s. Maybe they also ran into whine with the 2012 3.73s when initial testing?
This is just a theory I am throwing out, since it seems so odd that regardless how well built an 8.8 is when gears are added they whine.
Tom
Could it be due to the smaller pinion you end up with when going with lower gears? The twist on the pinion gear would be tighter and have less gear surface area to contact the ring gear. This may be part of the reason Ford decided to go with 3.31s. Maybe they also ran into whine with the 2012 3.73s when initial testing?
This is just a theory I am throwing out, since it seems so odd that regardless how well built an 8.8 is when gears are added they whine.
Tom
Tom, Ford used 3.31s only to get the 200mph, 60mph first gear and nice benefit of gas guzzler.
The 3.31s whine just like any other ratio with launching/sticky tires.
Guys don't swap gears and build rear ends to drive like miss daisy, so they get whine.
I still think the main issue is the 3-link UCA transmitting diff noise directly to the cabin, but I'm still hoping to find the fix that allows whine free 4.10s that take drag launches
-J
Users who are viewing this thread
