I have just purchased a set of 3.73 gears for my truck and was wondering if it was worth it to install them without also getting a posi unit. I went to the track saturday and was spinning quite a bit . My friend Joel Martinez (he is installing them) tells me I will spin more unless I get a posi unit due to more power. My current rear gear ratio is 3.42. Any help is appreciated!

15.40 @92.9 mph
2.49 60' stock wheels and tires

 

Well, I would say that it wouldn't be worth it to just install the gears if you had plans for a posi. But since your friend is installing it, I'm assuming it won't cost you anything??? then just have him install the posi later on.
If you had it done at a shop, might as well do it all at once cuz then you'd be paying double labor costs.
A posi, as opposed to an open differential, will spin both your tires instead of one.
For traction, work on other stuff as well such as tires, traction bars, etc.

 

Well I will look into a posi. What are some good ones and some prices?
I will also need a programmer now to correct the speedo after the gears are installed right?

 

Eaton is good. And yea you will need somthing to correct the speedo. Your chevy dealer may even be able to. Since its a factory gear option.

 

Yep. You can't go wrong with Eaton. They are rebuildable posis too, and I think that's why they cost more than the Auburn Posi. You can buy the preload clutches if they go out, and you can buy bigger springs too. I think they come with 400 lb. ones. You can get 800 lb. if you got serious power. Some1 confirm pleasE?
Yea, you will need some sort of programmer. My HPP3 does that.