Question about 3.42 to 3.73 gear swap

Rokgtar · August 6, 2006

Hello,

I am new to the site, though I have been reading for a while now. I have an 06 Silverado Z-71 crew, with the 5.3, Autotrac 4x4 and 3.42 gear. This thing is a real dog, both off the line and when towing a loaded trailer. I spoke with the dealer about having the 3.73 gears (front and rear) installed, but they gave me the story that it could void my warranty, cause noise issues, and cost several thousand dollars to do, and that they probably wouldn't perform the swap for me anyway. I am kicking myself for not getting the 3.73 when I bought it! I got a quote to install the OEM 3.73 gears at a local 4x4 shop (they told me that the dealers sometimes bring the trucks there for the same thing) for around $2000.00, and that there would not be any noise, because it is the OEM gear being installed. They did tell me that I would need to reprogram the truck computer so that it would know that it now had a 3.73 gear.

My question is, is it worthwhile for me to have this done? Or should I just tough it out, and get rid of the truck in a year or two? My 04 extended cab Z-71 had the 3.73 and was just right... Wish I still had that truck!

Ape0r · August 6, 2006

IMO if you're going to spend $2000 on it, make a bigger step than 3.42 to 3.73. If you really want it, find junkyard or e-bay axles with the correct gearing in them. Two grand is a LOT of money for a smallish change, especially on a brand new truck, and the dealer is right, no one is going to cover swapped gears under the factory warranty. Other things will be covered, but if they stick in 4.10s or 3.73s, that part of the truck will only be covered by the usual 12 month repair warranty (do they even offer that at all dealers?)

black&grayHD · August 10, 2006

I'm just planning a small gear jump, 3.42s to 3.73s for my truck. I've always wished that my truck had 3.73s from the factory, so getting a set for cheap seems like a good idea. I thought about jumping to 4.10s as quite a few have, but I don't race the truck or tow alot, so an all-around ratio is what I'm looking for, while still getting 20 mpg on the highway.

That said mine is just a 2wd, so it won't cost nearly as much to swap gears. I'm getting close to the end of warranty as well, so I'm not too worried about voiding it. In your situation I'd just stick with it, especially if you're planning on getting rid of the truck in a year or two

Schmids5.3l · August 10, 2006

I wonder why it costs so much, you can buy the gear, rings, and pinions from summit for 2-300$. They have a huge selection of gears and axles.

Installation is prolly a pain. Probobly just need the right tools though.

pm26 · August 10, 2006

It should not be that big of the deal for a fully equipped shop. They are blowing this thing totally out of proportion. Differential gears have changed very little in the last 40 years, and pinion/ring gear replacement was very common on vehicles in the 60's.

Properly shimming the gears is the key here, but it should not cost anywhere near $ 2k to do this.

I am glad I have factory 3.73s on my crew cab.

Truckman031 · August 10, 2006

It depends how long you plan to keep the truck. If you get the 3.73s, would you keep it for 5 years or so? If not, I would just stick with what you have.

Buggle_96 · August 10, 2006

It should not be that big of the deal for a fully equipped shop. They are blowing this thing totally out of proportion. Differential gears have changed very little in the last 40 years, and pinion/ring gear replacement was very common on vehicles in the 60's.
Properly shimming the gears is the key here, but it should not cost anywhere near $ 2k to do this.

I am glad I have factory 3.73s on my crew cab.

<{POST_SNAPBACK}>

Lol its no walk in the part. Our first install we had 3 guys and did it to my 88 cherokee. Installed 4.88s. Took us from about 9 in the morning until until 10 that night. given it was the first time we ever did it. It requires a bearing puller, shop press, blacklash tool and alot of tools plus a lift is about a must i think. All of which are not cheap.

Maybe its different on these trucks, but there are points where you almost have to take everything back out just to get the backlash correct. Pain in the ass, but 4.88s crawl

TEE · August 10, 2006

Hah....most are 3.2 something gears now!

Entryteam · August 10, 2006

I've got 3.42s and my truck pulls HARD. I'm over 300 bhp and 400+ ft. pounds of torque now, though, but I can roast my 285s without trying. Hell...I've got to be careful not to spin them.

I agree with just about ev everybody else...if you're gonna do it...go with the 4.11s and get positraction for sure.

-Ronnie