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Diff gear whine - 1030 rear axle

blkaplan said:
Maybe you heard wrong.
Click to expand...

But at least I can read...

Detroit Truetrac?
High quality mineral or synthetic gear lubes are
required for use in Detroit Truetrac differentials.
Regardless of the lube type, always use a GL5 rated
lube with the least amount of friction modifier. Mineral
lubes lacking friction modifiers (limited-slip additives)
were historically recommended for all Truetrac
applications because friction modifiers can slightly
reduce the bias ratio (limited-slip aggressiveness) of
Truetrac differentials. However, to address the
continually increasing power outputs of modern
powertrains, many vehicle manufacturers have
switched to synthetic lubricants as a counter measure
for increased axle temperatures and prolonged service
intervals. In general, consult the vehicle owner's
manual for the manufacturer's recommendations for
lubrication type, weight and fill volume. This will ensure
lube compatibility with the seal materials and bearings
used in the axle. Eaton Performance technical support
is available for any concerns in lube selection.
Click to expand...

Straight from the owners manual found here:
http://www.eaton.com/Eaton/ProductsServices/Vehicle/Differentials/detroit-truetrac/index.htm#tabs-4
 
Sounds like they prefer a mineral based lube but when the manufacturer uses a synthetic,,, they won't say to use a non synthetic...

Mineral lubes lacking friction modifiers (limited-slip additives)
were historically recommended for all Truetrac
applications because friction modifiers can slightly
reduce the bias ratio (limited-slip aggressiveness) of
Truetrac differentials.
Click to expand...

either way they strongly discourage any friction modifiers and the OP says he uses

"200ml of MotorCoat"
 
It's all about the pinion bearings. Noise that comes and goes by loading / unloading the drivetrain is almost always pinion bearing related. Constant noise is usually carrier bearing issue, but is less common. I'm not a fan of putting used bearings from one housing into another, they aren't that expensive.
 
Gear whine is also almost always load related.

Pinion bearings on the OP's car weren't touched, nothing swapped, only the carrier bearings which were new when the TT was installed.
 
I will be totally honest....I messed up pretty bad today on a differential install today on a 2008 Ford Mustang GT. I was using a ****ty flexible base dial indicator from Harbor Freight and somehow we set the backlash FAAAR too loose and on the test drive it whined. Tightened it back up to spec using the dial indicator properly, and whine went away! THEN, I messed up on the pinion flange install and didn't spec out the proper PRELOAD for the pinion and the nut was FAAAR too loose and we had grinding. sheeeeet. Then my research revealed it takes 200-400ft pounds (full man-strength on a LONG breaker bar) to get a new crush sleeve to crush.


To test if your pinion is shimmed correctly, you apply marking compound to the ring gear and check the engagement pattern.

You also need to tighten down the pinion flange nut properly so that you have the proper preload on the pinion bearings.


This is all stuff I have been learning recently myself, so I am no expert. Learned the hard way today for hours in 103degree heat in the shop.
 
Mode$6 said:
It's all about the pinion bearings. Noise that comes and goes by loading / unloading the drivetrain is almost always pinion bearing related. Constant noise is usually carrier bearing issue, but is less common. I'm not a fan of putting used bearings from one housing into another, they aren't that expensive.
Click to expand...

Interesting. Good to know.


Just one of the first links on the ol' google search for differential problems....:

http://www.differentials.com/technical-help/diagnosing-differential-problems


I am just taking a guess that the bigger wheels and tires have put a bigger load on the differential and now the problems have been exacerbated.
 
ZVOLV said:
To test if your pinion is shimmed correctly, you apply marking compound to the ring gear and check the engagement pattern.

You also need to tighten down the pinion flange nut properly so that you have the proper preload on the pinion bearings.


This is all stuff I have been learning recently myself, so I am no expert. Learned the hard way today for hours in 103degree heat in the shop.
Click to expand...

Honeychile, to check if pinion is shimmed correctly you read the numbers etched on the front of the pinion which may read "+2' or "-5" and then preferably with a minimum of sumthing like this:

wpe2.jpg


You check position of pinion..and disassemble and swap shims till it matchs the spec called out in the book plus of minus that gears deviation from theoretical ideal.
Google Image "checking pinion depth"
P1010001-3.jpg


camrear10.jpg


Here's the old "real Saab 900" and you can see the flange of the pinion bearing housing--the problem , revised 5-6 times that lead to so many Saab trans outright failures...
Pinion_depth_measurement_jig.jpg



I paid the rent for 16 years with Saab gearbox rebuilds--and in fact just sent last Thursday 100lbs worth of jigs and fixtures and measuring tools to a friend out in
Nude Hamster so he can rebuild his box using the 5.43 ring and pinion and the close ratio gear junk I just sent.

I think you really need to study harder and be more certain whatchoo are doing before you screw something up badly..
Solly
 
Hey I have the ability to be introspective and admit when I fugged it up and learn from my mistakes. Its how we all learn. To be totally honest, it was my first attempt at a diff setup. That's why I fugged it up. And the fact that there were up to six other people, including the car owner, underneath the lift at the same time and there was some beer drinking in triple digit heat that didn't make the job go any faster!

Had to drill out a snapped stud in the exhaust and then snapped extractor off in it. Then finally oversized the hole and thru bolted the downpipe to the manifold.


I didn't measure pinion depth, but just used the same shim that was there, installed new bearings, and confirmed it was ok by checking tooth pattern with marking compound. Why isn't that sufficient? I guess new bearings could change spec, but my limited research told me pinion depth very rarely needs to be adjusted.
 
Well I didn't have the tools to measure pinion depth. We just used the stock shim and confirmed tooth mesh pattern with marking compound. Seemed acceptable, so why mess with it? It was a ford 8.8. Have you ever worked with those? Ha
 
photo+3.JPG


For those who want to know how to do things correctly you will note that this example is marked +1

On everything that I have worked on--all European or Japanese, that means this is + one hundredth mm from the ideal blueprint dimesnion 0,01 is 3.9 1/10,000 of an inch or more or less 0.0004".

I cannot see 4/10,000...

They, the manufacturers, went to all that trouble to mark things just .0004" so it probably is important for long service life.....toofie patterns are nice and all but its still a judgement call looking at them...good judgement comes with experience.

Moral of the story is, if you don't have the proper tools, and the proper information and the proper working conditions, maybe don't screw with things till you do. It is not toooooooooooooo hard to get right with the right tools, the right info and right conditions.

Or shrug and argue on forums.:roll:
 
:lol: looked good when? I've honestly never worked on a rear end. I know if I did, I would have specs and measuring tools to do the job. Lots of reading, phone calls and probably crying, kicking, and throwing things.
 
centason said:
:lol: looked good when? I've honestly never worked on a rear end. I know if I did, I would have specs and measuring tools to do the job. Lots of reading, phone calls and probably crying, kicking, and throwing things.
Click to expand...


Ain't that bad..With all the right stuffs---including very good quality bearing pullers---and a good press, its mostly just tedious...Start with a "normal" spacer/shim stack, assemble, torque, measure, note, dis-assemble, change shims, reassemble, torque, measure, note maybe 3-4 times....

In some set-ups like the Saab 900 thing its kinda frustrating to do all this and spend $700-900 at cost on parts and beforwe you start you know that the case itself is marginal---no good past 230 hp---and that is super easy in a saab 16v turbo---and until the last revision in '89 that all the pinion bearing housings were highly likely to fracture at the base of the flange.....

But if things look good, what could possibly go wrong?:e-shrug:
 
Trial by Fire. That's how we learn. I got paid OT to fugg it up, so lesson learned... We will get it done one way or another.

Oh yes it took the shop press and the correct dies/puller/cutters to even get the old bearings off and new bearings on....

Yo johnv, we put pulled the 3.30 ring and pinion and put in Ford Racing brand 4.10 ring and pinion gears. All new bearings too. Whatyougottasay?

http://fordperformanceracingparts.com/download/instructionsheets/fordinstshtm-4209-8.pdf
 
Yeah the shop wasn't at peak efficiency with a bunch of bastards in the way. And lax coworkers leaving nuts and bolts and precisely machined measuring shims all over the place. We did our best, but it was more of a party than an efficient install! Ha. We did all learn a lot, but I might just be speaking for myself...

The digital caliper was being a piece of crap and so was the dial indicator. Flex base was stupid. Needed magnetic base!

Clean, uncluttered, proper work environment is paramont when doing something precise like that. We run a clean shop but when too many bastards get in the way it makes it harder.

The old mantra is, "$100 hour if I do it. $150 if you watch. $200 if you help!"
 
First test drive:whining

Fixed sloppy backlash, second test drive: grinding! We found the pinion flange was sloppy. Over 10mm of movement! We didn't set the preload right! It takes serious torque to crush the crush collar! The "Big Guns" (1/2" impacts) didnt do it. They go to closer to 200lbs max. We were slamming the pinion flange nut last night and it just wouldn't go down the splines! We called it a night.

Bossman called today and said he pulled the Ford 8.8 back apart. Of course, anytime you hear grinding...damage! He said he saw some. Meh, (shoulder shrug). We will fix it...
 
Success

Parking brake set, pinion flange counterheld with a length of steel bolted to flange, manstrength and a 27mm socket got that pinion flange nut tight enough.


Pinion flange preload set. Slight damage to carrier it sounded like....I think the pinion gear slid back and hit the carrier. I don't know. Didn't see it.

But anyways, after pinion preload was set the car drove just fine!
 
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