Originally Posted by Toreador_Diesel

Well boys, the deed is done and the 4.30s are in.

The Good:

When I first put it into gear and tipped the pedal it jumped forward, really wanting to go. (I hadn't even driven anywhere and I was already impressed.) Driving around town, the tranny shifted so smooth and crisp it was like I had a new truck. Once I got on the freeway, I was blown away as to how much easier my truck accelerated to 65. On certain hills that would work my turbo until it started to flutter, it would barely use the turbo. With the 4.30s, all I would hear is the sweet, but quiet whistle of my turbo yawning at whatever I threw at it. Mileage wise, I did see a promising increase the overhead lie-o-meter said 16.2 mpg instead of it's usual 14.0 mpg or less. I had to pace myself for the first 100 miles per the shop, but once that was over I mashed it from a dead stop and was a quarter mile down the road before I knew it.

The Bad:

The only thing I noticed that bothered me was that my RPMs were much higher than stock and my truck was really getting up there (and staying up there) just to shift sometimes. I also noticed that I didn't have much passing power or any real power up top. My truck was turning 3100-3300 rpms, just to pass someone and really get down the road from 45 to 65. (even then it wasn't going too far, too fast) I thought I needed a new, custom chip and upon talking to a few reputable, independent, well known sources (Well-Respected FTE vendors), I was told that I had made an $1100 mistake. In other words, I had over compensated for my tires and my application. If I had 37 inch tires, 4.30s would've been perfect for what I was looking to accomplish. Another $750 later, I found that they were dead on right and everything is as it was before I lifted my truck; with 4.10 gears installed, my rpms are where they should be 65mph=1900rpms, 70mph=2000rpms, 75mph=2150rpms, and so on. My power and mileage has also recovered to stock levels, i.e. 18.6 mpg. We'll see just how good it gets as time goes on, but things are looking better already. I had convinced myself that 4.30s were the way to go given the rolling resistance and a few other factors mentioned. But I didn't think it was going to make that much of a difference between the 4.30s and the 4.10s. The power of the 4.30s was awesome, it truly was, but it was overkill for trying to recover my fuel economy. My expensive loss can now be a V10 owner's gain; the gears alone cost me $450, so they're currently for sale in the classifieds section for $350 obo. From what the guys at the shop said, these are high-quality, premium gears that will last a lifetime, so if you're interested, check out the ad.

Originally Posted by Stewart_H

I found it:



If anyone doubts the info being posted here about using 4.10's with 35" tires and NOT 4.30's, please take it from Tor's own words. He ended up spending more to fix the mistake of going with the 4.30's.

Stewart