Took the truck to a shop this morning because of a "whirring" sound in the rear. They called and said the differential needs to be replaced. Tonight I'll go figure out just which diff I have. The shop mentioned that the diff is a 3.55, if that narrows it down somewhat. The truck is a '99 1500, 4X2 w/o factory tow.

Questions:
1) I read that our diffs don't last therefore getting a junkyard diff is a bad idea. Agree?

2) I tow a race car with it, so upgrading to a better diff has it's charms. Are there heavier duty rear ends that are compatible? Like maybe I could get a rear end from a 3/4ton truck and put it on? Apparently there were a lot of possible diff options with my truck, would any of those be a particularly good replacement for mine if I found it in a junkyard?

3) What is your favorite course of action to overcome this? New OEM replacement? Rebuild? Aftermarket replacement? The shop quoted me $1500 to replace, $500 of it being labor.

Thanks guys,
-Scott

 

First off, 3.55 is just the gear ratio. It does nothing to help identify which axle you have as that gear ratio was used in most of them. If it hasn't been removed, all Dodge axles have two metal tags mounted under the cover bolts. One on the left side under two of the bolts, and one near the bottom under 1 bolt. This should help you identify your axle. 1500 V6 and V8 models could have the corporate 9.25" or a Dana 60. Some rare ones had the Dana 70, which can be found in 3/4 ton trucks with either the V10 or diesel engines. For towing regularly I would prefer at least the 60 with a LSD. The 70 would be a better option as it has better brakes and is a bit stouter. Properly cared for, the Dana axles hold up very well. I wouldn't hesitate to get one from a junkyard if you can find one in good condition. $1,500 is not bad for an axle overhaul assuming he will be replacing all the seals and the ring and pinion set, but I wouldn't spend that on a 9.25" axle. For the towing you do a 60 is almost a requirement.

 

An easy way to tell which differential you have is to look at the cover. The corporate has a cover shaped like a stop sign (octagonal), the Dana 60 & 70 have a cover that looks like it's pointed at one end.

 

ive never heard of a half ton with a 60 from the factory
and if you only towing a race car, you should be just fine, now if you were pulling a pro stock pulling tractor, then you'd need something bigger

 

Me neither, but I was proven wrong just this past week on this in another thread.

https://dodgeforum.com/forum/2nd-gen...l-experts.html

Hauling a car is no simple task. Not only is the car heavy, but the trailers are usually pretty heavy, too. If he's like the racers I know then he's got a heavy toolbox and an extra set of tires on there, as well.

 

You might have been wrong, but that dudes truck is a 2500 not a 1500.