Rear gears advice - 55 Pontiac

Not being a GM guy until I got the Pontiac I'm not familiar with what fits what. So my Ponch has a small whine in the rear end that I just don't like. Am planning on rebuilding it. I think it's a 3.73 now but am not sure. It was a 700R4 so are the 3.73s the best gears for a Cruiser or would another ratio be better. I want good mileage without giving up to much performance.

 

With that overdrive transmission anything between 3.50 and your 3.73's are very compatible. You need a little gear to the that Pontiac moving and the overdrive will let the rpms be in a good range going down the road.

There are a lot of factors too, like when your cam comes in, but generally those ratios will get you good results.

Don

 

If the howl is around 55 mph it could be normal. I had a lot of 55 chevys over the years and they all seemed to have a 55 mph howl.

 

all my 55 pontiacs had a rear gear howl,{3 of em}

 

If it's a factory rear, it's a choice of being most likely a 3:23 for auto and 3:64 was standard for manual trans. The 3:23 is a very good gear for cruising and it also has the help of the low first gear of the 700r4 for take off. 3:73 was not available. 3:90 was the next lowest gear.

 

Every GM product that I have owned howled at 55 too.