installed 4.10 gears in 8.8

[broncobuckinaround]

did the 8.8 swap into my b2 and have installed 4.10s to match the front axle.

when i drive and hit just about 30 mph it starts to hum

new barring, race, crush sleeve. shimmed diff to have .0625 back lash. or 1/16 of an inch.

maybe i messed up

 

[Curious Hound]

Did you install different tires, too? Are you sure it isn't the new tires causing the hum?

Did you get the contact pattern centered up good on the gears?

Just wondering. I plan on putting the 8.8 under my Ranger pretty soon.

 

[Blown]

Ya, you did not mention checking the contact pattern between the ring gear and pinion??? That is the final check.

 

[monstermazda]

Did you go you break in then gears? Blown right make sure you have a healthy pattern. Break in gear drive under normal load (no towing or hauling) for 30 mins at different speeds let gear cool (I let them cool over night) change fluid and run easy for 500 miles.

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[Blown]

https://www.ringpinion.com/Content/Book/Reading-and-Adjusting-Ring-and-Pinion-Tooth-Patterns.pdf

 

[Hagan]

What brand of gears? I set up my 9" on my Bronco and it howls. Some people say it will go away and it's caused by cheaply machined gears

 

[monstermazda]

And that back lash should between .008-.015 that's out of my gearing book for that model. Could be to tight

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[Captain Ledd]

The backlash should be around .008-.012

Page 17 out of 31

http://performanceparts.ford.com/download/instructionsheets/FordInstShtM-4209-8.pdf

Edit: DOH! Monstermazda beat me by one minute. Basically the time to took my to verify. That backlash is way too loose.

Another edit: You are checking that backlash with the pinion flange fixed right? not just with the driveshaft slop and everything else? Just making sure we cover all the bases.

 

[broncobuckinaround]

wow thanks guys for all the great info. im going to assume they are to loose.

no i didnt check the pattern. like an idiot i was to much in a rush to get it done before my hunt this weekend.

if i leave it like that and not beat it will it last through the weekend.

i have a friend who has the back lash tool he'll let me barrow.

if it will last through the weekend i will barrow the tool and get the marking paint to check my pattern.

hegan; i dont know the brand because they are used gears i bought from adsm08.
ericbphoto; i did think about the tires. they do make noise too. i jacked up the rear end to confirm what i was hearing. for sure was the diff humming

 

[adsm08]

The gears are OEM Ford, taken from an FX4 L2.

 

[Hagan]

The gears are OEM Ford, taken from an FX4 L2.

Then they definitely shouldn't howl.

You need to take it back apart and have it set up properly. No guessing should be involved lol

 

[broncobuckinaround]

humming is fixed. thanks everyone for the help. it is now shimmed to between 0.08 and 0.15

no more humming.

 

[Curious Hound]

Glad it's fixed.

But you say you got the backlash between .08 and .15. Is that what you meant to type? The decimal is off.

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[broncobuckinaround]

yes sorry for the mistake. i was rushing out of the house. lol