When i let off the gas, in my 66 289 auto it whines. If you barely press the gas while cruising it'll go away, but if you let it go it whines. Is it the transmission or the diff. DO you think i should replace the diff fluid?

 

Ive never heard of that, but its probably not the differential, those are pretty quiet, when was the last you changed the fluid in the diff, it might be time anyways.

 

Well, I bought the car over a year ago, and never changed it, even though i should. I will as soon as i get the chance.

 

you might as well do it, its not hard, and its cheap . If that isnt the problem you'll know soon enough, and it wont cost you $10

 

I found some info on your problem, you could get checked out.

Question: I recently began to hear a "whining" or "howling" noise coming from the rear of the car at 65 miles per hour. It seemed to become louder when you tried to accelerate to maintain your speed. The noise was considerably less if you took your foot completely off the accelerator. I took it to a local dealer expecting to find a differential problem (pinion gear or something). They replaced the drive shaft and the noise at 65 mph went away. However, I still hear a minor howling at around 55 mph. It doesn't seem to change if you accelerate or let off the pedal. It really doesn't sound like singing tires. It may just be paranoia since I only have about 5000 miles left on the warranty. Do you have any suggestions on how I can see if this is normal or if I could have early signs of a differential problem? Thanks, Stan

Answer: Without seeing and driving your car, we can only make an educated guess. You may have an axle bearing or possible bearing in the differential that is starting to fail.

But it hard to say if this pretains to you or not.

 

Well, Mine gets louder when you let off the gas. I believe it's a wheel bearing or something.

 

yeah I rule that out either.

 

We had a 64 Chevy truck that whined when you let off the gas. We kept on driving it until the pinion gear made a hole in the bottom of the differential. I would change your fluid to a synthetic and see if that changes anything.

 

When you are changing fluid I would check the backlash and ware patteren. I had one that did the same thing and it needed to be reshimed because some one was in there and didn't set it up right the first time. It doesn't show up untill a few miles later!!!!

 

With your car on stands grab the diffential pinion flange and see if there is any lateral movement. Without hearing the noise it's hard to give you good advice. What I can tell you is that whining from the differential on deceleration is most commonly the pinion bearing closest to the flange. Whining on accleration is usually the bearing closest to the pinion gear, Whining on turns is a wheel bearing, or your girlfriend because you're driving too fast . Whining coming to a stop at the bank means you probably need a second job, to pay for that 9+ Currie.