rear end noise

[fordsohc46]

got a 78 bronco with a 9 in. it has a terrible howling noise above 35 mph if you are pressing the gas. let of to coast and it goes away. there is slack in the pinion yoke. do you think i can just tighten the yoke nut or should i teardown the rear end. i just bought the truck and it has been sitting for a while but i don't know how long the rear ends been run loose.

 

[Broncobill78]

got a 78 bronco with a 9 in. it has a terrible howling noise above 35 mph if you are pressing the gas. let of to coast and it goes away. there is slack in the pinion yoke. do you think i can just tighten the yoke nut or should i teardown the rear end. i just bought the truck and it has been sitting for a while but i don't know how long the rear ends been run loose.

Well if there's slack in the yoke it worn't hurt to tighten it down since it's *already* howling and if it's cooked then the damage is already done. By any chance have you checked the fluid level ? It should be right level with the check-plug which comes right on out if you just stick a 3/8" extension in there without a socket on it (or is it 1/2" ?, damn I hate getting old). Don't just assume it's the rear, try removing the rear shaft & running it in 4WD on just the front axle. If it still makes noise then you need to look elsewhere but if it gets quiet then you've started to isolate your problem.

 

[fordsohc46]

check it in 4wd with rear shaft out still had noise but not as loud. took chunk out of rearend today found black metal sludge as lubricant. bearings all shot but good news is gears look fine. also wandering how to check my gear ratio. cant find tag. i think its 3.50 because the pinion has 10 teeth and the ringgear has 35. does this sound right.? thanks for the help.

 

[Broncobill78]

check it in 4wd with rear shaft out still had noise but not as loud. took chunk out of rearend today found black metal sludge as lubricant. bearings all shot but good news is gears look fine. also wandering how to check my gear ratio. cant find tag. i think its 3.50 because the pinion has 10 teeth and the ringgear has 35. does this sound right.? thanks for the help.

yup, that's it. 35 on the ring & 10 on the pinion is a 3.50.

 

[freak]

Your gear is shot too. Trust me on this, with it howling for a while your just be eating the gear up again if you use them over. Buy I new set. I trashed out a brand new gera with in 20 miles cause the nut backed off. I've done dozen's of 9" rear's to know.