Just purchased a 2006 Tahoe Z71 103,000 miles and very clean. I knew going in that the vehicle had the tow package and a 4.10 rear end, but I would rather have a ratio that is a little better on the fuel.

How big of a deal is it to change the final drive ratio and what will it gain me? I am not wild about changing the whole differential and would rather change the gear set.

I understand this has to be done correctly and I believe I could find a competent mechanic.

What is involved here? What other things will it affect, Speedo? Tach? Other stuff in this tricked out vehicle?

Thanks for reading... Gary

 

Can anyone give me some advice on this subject?

 

if its a 4wd your probably looking at $2000 in parts and labour for front and rear diffs. That buys a lot of fuel.


I doubt that you will see anything significant in fuel savings. 1-2mpg. That rear end is fantastic imo. I driven trucks will the lower ratio rear end and they can't tow and have poor power.

 

I'll go along with tech2 on keeping the 4.10, that's really a good set for power/tow, and, if mpg is the only thing that's of concern, I doubt if you'll realize that much, compared to the cost of the change. I know you'd prefer not to, but, if you must, it might be cheaper/easier if you just buy a complete differential (if 2WD) and swap it out. Anything that you get that's within the OEM for your year would be able to be easily set in the computer.

 

Don't waste your time or money. Between the gears, hassle, labor, and don't forget changing your speedo sensor, it's simply not worth it...

 

There was a lot of anecdotal data during the first year or so of the GMT900s being on the road that the 4.10 gears were actually getting better gas mileage than those with numerical a lower gear ratios.

 

Would a cheaper way be to put larger diameter (2 sizes up) tires on it then recalibrate the speedo if possible?

 

Ok. Now I haven't any idea what rear end is in it. Dealer that sold me the truck swears it is a 3.42. The truck has the original sticker that says 4.10
Can any that knows their fd ratio tell me what speed/rpms you run at 70 mph?

 

Go old school. Put it up on jack stands and turn the drive shaft by hand counting the turns to get one full revolution on the wheel. 4 and a little its 4.10, almost 3 1/2 its 3.42. Wish mine had a 4.10 in it. Even the 3.42 would be better than what I've got.

 

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