Adding factory limited slip and 4.10 gearing question

[TomsBeast]

Originally Posted by boywonder

The whine on decel means that the ring/pinion are not shimmed properly; this needs to be sorted out when they get the correct Diff installed.

Replacing ring and pinion requires shimming the pinion (for both position/engagement with the ring and pinion preload) and shimming the ring gear for backlash. Insufficient backlash can cause whining and may result in excessive wear on the teeth. Excessive backlash can cause clunking when coasting or when first accelerating since the teeth are too far apart to engage properly.


The engagement of the teeth is checked using grease paint and reading the resulting pattern of the paint on the teeth after shimming by spinning the gears; it's a tedious iterative process to get the pattern correct.


That being said my re-geared diffs (front and rear) don't whine.....a correct setup shouldn't whine or clunk.

yep


It's conjecture on my part, but my guess is the guy going through the iterative and sometimes tedious task of shimming and pattern checking 'got it close enough', knowing he'd have to repeat the process from square 1 when the correct LSD comes in, but after the test drive it whined more than he expected, and just went with it. Depending on how bad the whine is, "a little noise but not bad", or a "full blown howl" would tell me how many miles I'd want to put on it. Certainly if it gets louder, stop driving it.

Originally Posted by boywonder

Not sure there is a possible tooth combo to get 4.09..but who knows.......

it's that 'new math'

[boywonder]

Originally Posted by TomsBeast

It's conjecture on my part, but my guess is the guy going through the iterative and sometimes tedious task of shimming and pattern checking 'got it close enough', knowing he'd have to repeat the process from square 1 when the correct LSD comes in, but after the test drive it whined more than he expected, and just went with it.

That's what I'm thinking too....the preferred way would be to reinstall the old gear set with the old shims where they were while your wait for new LSD.


I did that when my buddies wanted to go camping/riding during the re-gear....I was waiting on shims or something.

[itnanti]

Originally Posted by TomsBeast

yep


It's conjecture on my part, but my guess is the guy going through the iterative and sometimes tedious task of shimming and pattern checking 'got it close enough', knowing he'd have to repeat the process from square 1 when the correct LSD comes in, but after the test drive it whined more than he expected, and just went with it. Depending on how bad the whine is, "a little noise but not bad", or a "full blown howl" would tell me how many miles I'd want to put on it. Certainly if it gets louder, stop driving it.






it's that 'new math'

Thanks for the advise.

[rescuejg]

Shouldn't be any noise from properly set up gears.

[SierraHawk]

Two sets of 4:10 gears were installed when Heber put the 4X4 platform under my van. Primary problem I had with the rear diff was the repeated failure of the Ford factory LSD. After the third stock LSD failed, I had an Eaton True Track installed in the rear diff. That was 5 years ago. The Eaton pops and grinds on sharp turns when the van is accelerating but it keeps moving forward. Emptied the diff oil several times but found little to no metal fines. 4:10 front and back does well on the road and off. Two years ago the passenger side rear axle disintigrated. Called Randy's Ring and Gear. I was told that there was a problem with the steel that the mfg used. New axle cost $500. Guy at Randy's said that if the new axle fails they would send a new one but who is going to pay for the tow ($1500 to $2000 to be towed from Death Valley to Pahrump), cleaning out the pumpkin and gears and reinstalling the new axle? Fortunitly my axle crumbled in my mother's driveway after we drove the "Buttermilk Loop" west of Bishop. It took me three weeks to get the replacement axle. Fortunately the new axle has not failed...yet.

[itnanti]

Originally Posted by SierraHawk

Two sets of 4:10 gears were installed when Heber put the 4X4 platform under my van. Primary problem I had with the rear diff was the repeated failure of the Ford factory LSD. After the third stock LSD failed, I had an Eaton True Track installed in the rear diff. That was 5 years ago. The Eaton pops and grinds on sharp turns when the van is accelerating but it keeps moving forward. Emptied the diff oil several times but found little to no metal fines. 4:10 front and back does well on the road and off. Two years ago the passenger side rear axle disintigrated. Called Randy's Ring and Gear. I was told that there was a problem with the steel that the mfg used. New axle cost $500. Guy at Randy's said that if the new axle fails they would send a new one but who is going to pay for the tow ($1500 to $2000 to be towed from Death Valley to Pahrump), cleaning out the pumpkin and gears and reinstalling the new axle? Fortunitly my axle crumbled in my mother's driveway after we drove the "Buttermilk Loop" west of Bishop. It took me three weeks to get the replacement axle. Fortunately the new axle has not failed...yet.

This thread is starting to keep me up at night[emoji2359]

[boywonder]

Originally Posted by itnanti

This thread is starting to keep me up at night

If the stock (Dana Trac loc) LSD fails, it operates like an open diff....same as when the clutch packs wear out....you can still drive the van without issue. If the ring or pinion fails different story.


Axle failures are not uncommon on semi-float axles on heavy vans; full float axles do not have this issue. Full float axles have a hub the sticks through the hole in the wheel, semi floats do not. With a semi-float axle, the axle supports the weight of the vehicle, with FF axle the hub supports the weight and the axle just transmits torque to the wheels to move the vehicle down the road.

[ibike]

Originally Posted by boywonder

I just re-geared my 2008 5.4L from 3.73 to 4.10......

Not to derail the thread, but I’m curious to hear how the jump to 4.10 is working for you. I’ve also got a 5.4 van with factory 3.73 that could use a little more umph going up hills. It’s hard to keep the van from jumping back and forth from 3rd to 2nd, hoping going up to 4.10 will help me hold 3rd gear. The motor seems to pull the hardest around 3500RPM

[LSretired1]

Does this post mean that you have turned off OD and that the van hunts between third and second gears. At what speed?

[boywonder]

Originally Posted by ibike

Not to derail the thread, but I’m curious to hear how the jump to 4.10 is working for you. I’ve also got a 5.4 van with factory 3.73 that could use a little more umph going up hills. It’s hard to keep the van from jumping back and forth from 3rd to 2nd, hoping going up to 4.10 will help me hold 3rd gear. The motor seems to pull the hardest around 3500RPM

What size tires are you running?

I'm running 285/70-17's and the 4:10 gearing helped quite a bit. It still downshifts out of OD on long grades but I can usually hold 3rd gear and the speed. With the 3.73's it would sometimes downshift to second gear and I'd be going 45mph at the to of the grade.....

With the above tires and 3:73 gearing the speedo read low by about 10%..now it reads low about 2-3%. So it's still technically geared at little taller than stock.