I have a Dana 44 in my Vette. It has been about 3000 miles since I installed it but prior to installation I took it to differential shop and had all the bearings and seals replaced and the gears checked and adjusted. Up until now I hadn't noticed any noise but now I am hearing a howl between 60 and 63 mph. This is a noise at steady throttle but stops when I let off the gas and comes back under acceleration but disappears around 64 mph. The differential is full of oil. I am thinking it is the adjustment on the ring and pinion gears. Any one with experience on differentials have an opinion?? Thanks

 

Check the pinion nut for proper torque. I don't know if your differential uses shims or a crush sleeve. The procedure varies.

While the following link is not specific to a Vette, it may help you.

http://www.dippy.org/svcman/sm03.html#TOP

 

It sounds like the ring and pinion gearset creating the whining noise indeed.

Did you reuse the old and ring and pinion gearset ?

On high milage differentials and reusing the original ring and pinion gears, You have to maintain the exact original pinion depth and backlash settings. Or a gear whine results while driving at speeds typically around 47MPH to 70 MPH. It dissapears at slower speeds and at higher speeds that stated above.

You are dealing with tolerances of + or - .001 inches when properly setting up a performance car differential such as your Corvette.

+ or - .0005" is the tolerance I allow for when I overhaul High performance Diffs. From the stated Pinion depth and backlash settings. + or -.000" is allways my target goal, but very hard to achieve belive me.

Hard to say what went wrong with your Dana 44 rear diff during the overhaul without looking at it 1st hand. I can only speculate from here.

A gear pattern test will show alot. But you must have alot of prior experience at reading them correctly.

Some aftermarket Ring and Pinion Gearset will create gear whine too while at speeds stated above. They can be at times impossible to remove. Because most aftermarket ring and pinions use a different gear tooth Nomenclature - profile shape than what the OEM's used.

The aftermaket 1st goal is maximum gear tooth strength. Gear whine noise is Secondary worries too them. They figure threre gearsets are going into all out race cars with OPEN Exaughst. And You will never here a ring and pinion whining then.

You are likely going to have to go back inside of Your Dana 44 to reinvestigate. It can be frusterating removing a gear whine noise. LOL

Differential Housings get sprung at times too. Complicating matters. Then it is totally impossible to get a proper ring and pinion picture perfect gear tooth profile on the drive and coast side. The gear whine will allways be prevailent in that rear end housing with any Gearset used.

 

87 vette 81 big girl thanks for the in depth analysis. It confirms my thoughts. They did use the original ring and pinion gears as they looked to be OK and probably are. I think I will leave it for a while and if it gets any louder I will have to pull it out and have a professional look at it. I know better than to try and fix a differential myself.

 

You can Overhaul that Corvette Dana 44 Yourself, It is not the easiest Rear Differential to overhaul in use out there in the High Performance World we know of.

Ranks up there high on my list of Differentials to overhaul correctly.

Everybody has to start learning somewhere if you have the ambition to.

If the Gear Whine Noise finally gets to you enough, Consider Purchasing a New Ring and pinion Gearset.

The 1985 to 1996 Corvette Differential is known as the Dana 44 HD.

Different from what what gears is used in the 4wd - 4X4 applications.

I belive the Dodge Viper also uses the Dana 44 HD gearset also.

Yukon Gears makes a very good gearset. I have used them numerous times through out the years with good results. They set up easily with Good Gear tooth Pattern test results. And driving down the road. Quiet if You get the Pinion Depth and backlash settings dead nuts on.

BR