Finally Did It...

GM Dude · April 16, 2007

After about a month or more of research on changing out differential gearing, I decided to dive in. My 2005 GMC Sierra 5.3L w/3.23 gearing was just a DOG after installing 20" tires and trying to tow a boat. I just could not stand it anymore so I finally installed 3.73 gearing and a Wait4Me performance tune that got my speedo corrected for the tires and gearing as well as removal of torque managment and governor limits. I also had Jesse modify transmission shifts etc. etc. etc.. Since I just installed the new gearing, I just don't want to get on it just yet to see what the tune has done but I'm telling you the gear change itself has made a big difference. This was my first gear change and it was about a 7 hour job for me but could do it again in much less time and it was not as bad as I thought it would be. I'm hoping the performance tune will make this truck rock. I had to drive several days after the gear change before I got the tune and it sure is nice to see that darn ABS/Brake light go out and a correct speedo.

If your thinking about changing gears and you have the tools to do, don't hesitate as it's well worth the time. Dealer would have done it for $1200 not including the tune of course and I did it for under $600 including the $157 tune and 7 hours of my time. I wish to thank everyone here for the courage after reading many posts.

ken1mod · April 16, 2007

You have my genuine respect for being able to change gears. This is not an easy thing to do. I would dive into an engine in a heartbeat but gears scare me for good reason.

3.23 are just wrong for any loaded condition. You did good!! I am proud of you.

I have 3.73s and they are a good all around choice. I get almost 19 mpg in mixed high altitude, hilly driving. Sometimes I wish for the 4.10s though. Usually when a Ford or Dodge is next to me. Fortunately, I have 454 SS stickers on my 5.3 and nobody will take the chance to race me.

Ken

david.mciver · April 17, 2007

Fortunately, I have 454 SS stickers on my 5.3 and nobody will take the chance to race me.

A sheep in wolves clothing!

Big Tool · April 17, 2007

I'm sure you're going to love the new gears and tune. Did you have 3.23 or 3.42? I've never heard of 3.23 gears in a cheby, Unless it was a 2wd. Either way you mad a great decision. My dad's avalanche with 3.42 gears is an absolute dogggg with any trailer behind it. It will pull good enough, but OD is just not an option with any load. Even with my little rhino and trailer it is constantly downshifting. My avalanche with 3.73's did much better.

GM Dude · April 17, 2007

You have my genuine respect for being able to change gears. This is not an easy thing to do. I would dive into an engine in a heartbeat but gears scare me for good reason.

3.23 are just wrong for any loaded condition. You did good!! I am proud of you.

I have 3.73s and they are a good all around choice. I get almost 19 mpg in mixed high altitude, hilly driving. Sometimes I wish for the 4.10s though. Usually when a Ford or Dodge is next to me. Fortunately, I have 454 SS stickers on my 5.3 and nobody will take the chance to race me.

Ken

Why thank you kindly Ken. I do admit I have some mechanical background and all the tools necessary to complete the job. Hardest part, I thought, was tightening that darn pinion nut to crush that crush sleeve and the rest really was not bad. Don't get me wrong, it was a pain working under the truck becuase I did not remove the axle.

GMCMAN06 · April 17, 2007

After about a month or more of research on changing out differential gearing, I decided to dive in. My 2005 GMC Sierra 5.3L w/3.23 gearing was just a DOG after installing 20" tires and trying to tow a boat. I just could not stand it anymore so I finally installed 3.73 gearing and a Wait4Me performance tune that got my speedo corrected for the tires and gearing as well as removal of torque managment and governor limits. I also had Jesse modify transmission shifts etc. etc. etc.. Since I just installed the new gearing, I just don't want to get on it just yet to see what the tune has done but I'm telling you the gear change itself has made a big difference. This was my first gear change and it was about a 7 hour job for me but could do it again in much less time and it was not as bad as I thought it would be. I'm hoping the performance tune will make this truck rock. I had to drive several days after the gear change before I got the tune and it sure is nice to see that darn ABS/Brake light go out and a correct speedo.

If your thinking about changing gears and you have the tools to do, don't hesitate as it's well worth the time. Dealer would have done it for $1200 not including the tune of course and I did it for under $600 including the $157 tune and 7 hours of my time. I wish to thank everyone here for the courage after reading many posts.

Is this a 4x4? If so you have to change front and rear right?

GM Dude · April 18, 2007

GMCMAN06...No, it is a 2WD but you are right, both front and back would have to be done on the 4X4

svensk · April 18, 2007

Omfg...you did the gear swap without removing the axle....nice. I heard it's easier to just buy the whole axle you want from a junkyard and just swap the whole thing out.

asilverblazer · April 18, 2007

A LOT easier...

GM Dude · April 18, 2007

A LOT easier...

Easier, absolutely, but you can't beat the experience it gave me and the satisfaction that I was able to do it. Believe me it crossed my mind many times....dealer....junk yard axle....dealer....do it myself...junk yard axle...do it myself - you get the idea. I really decided to do it myself for the experience and I know a new set of gears and bearings are in there and not something that might have 50,000 hard miles. Cost was also a large part of the deciding factor