Swap rear 3.08 gears for 3.42

[HeidiHoe]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics, please.

IMO, a tune would be the best option for you, and you will get the additional advantage of getting your TCM tuned for better transmission shifting performance.

GM website regarding the PPV Tahoes says that the outfitter reprogramed the transmission to shift at higher rpms than stock. I havent put many miles on it yet and havent had an opportunity to stretch its legs yet

 

[HeidiHoe]

I think a Tech2 can change the tire sizes.

Maybe post this over in the PPV/SSV section and see what those who own these say.

Sent from my SM-G930V using Tapatalk

That is am excellent suggestion, thank you

 

[GoToGuyRon]

Hello all, I just picked up my PPV. It has smaller tires than the civilian models and I have a set of 275/55R20 michellin defenders to replace them. Hi, i did a research and math. Doing nothing with the 20's installed. Your indicated (speedo) at 55.5 mph, your actual speed of movement will be 60. Or conversely. The 17's at 65 mph, 2278 rpm. With the 20's , 2278 rpm will actually be 70 mph. So with larger diameter speedo will be 5 mph under. I did the math with your 3.43 regear. Not pretty unless your pulling stumps. Later

 

[Bill 1960]

Regarding your original question, the cost for the parts is similar whichever way you go, gears vs axle housing. Labor time isn’t much different either.

The advantage for a housing swap is most shade tree mechanics can do that in their driveway. Fewer people have the skills and tooling for a gear swap so they end up hiring it done.

The advantage for a gear swap is you end up with a known all new moving parts assembly, compared to the unknowns of a recycled assembly.

 

[GoToGuyRon]

The one problem, important maybe. High perf' vehicle, option codes, does it have limited slip (positraction, locker) ? Your known is that it came eqipt with higher performance parts. Retaining your known parts and swapping out ring and pinion would be my move. Bigger risk obtaining an unkown history unkess you plan on rebuilding a used unit. You will still have update the "brains ". The computer will have to be informed of applicable changes for optimal performance. I did some math and your cruise rpm would be substantially higher. Your mileage would take a hit.

 

[1BADI5]

On my '10 PPV I went from 3.08 and open diff to 3.73s and limited slip/locker

Great mod for the money. I went with Yukon Gear and Axle, ring/pinion, Duragrip and complete master install kit.

 

[HeidiHoe]

Thanks to all I talked with a young but gifted gearhead about what i wanted to do and he went on about unsprung weight in great detail. Apparently the steelies and tires originally equipped on the PPV offer an excellent combination of traction and handling characteristics that swapping to 20 inch rims and tires would compromise. My PPV is equipped with a limited slip locking rear end with very low miles on it so until I am ready for a revamp I think I will leave it as is. I drove this bad boy conservatively for 280 miles at 60 mph and achieved 23 mpg so for now I am happy.

 

[HeidiHoe]

The one problem, important maybe. High perf' vehicle, option codes, does it have limited slip (positraction, locker) ? Your known is that it came eqipt with higher performance parts. Retaining your known parts and swapping out ring and pinion would be my move. Bigger risk obtaining an unkown history unkess you plan on rebuilding a used unit. You will still have update the "brains ". The computer will have to be informed of applicable changes for optimal performance. I did some math and your cruise rpm would be substantially higher. Your mileage would take a hit.

The plan was to change to 3.42 but with a larger tire (275/55R20 vs 265/60R17) which would leave the overall combo within 2.5% of each other. Computer wouldnt even notice

 

[thompsoj22]

Thanks to all I talked with a young but gifted gearhead about what i wanted to do and he went on about unsprung weight in great detail. Apparently the steelies and tires originally equipped on the PPV offer an excellent combination of traction and handling characteristics that swapping to 20 inch rims and tires would compromise. My PPV is equipped with a limited slip locking rear end with very low miles on it so until I am ready for a revamp I think I will leave it as is. I drove this bad boy conservatively for 280 miles at 60 mph and achieved 23 mpg so for now I am happy.

Function and reliability are the benefit for making the choice to keep the original configuration of the vehicle. You got some good info from the "gearhead" that saved you time and money plus the unforseen time and money of making modifications to your drivetrain. Enjoy your new PPV which is way cool just as it was designed!

 

[HeidiHoe]

As suggested, I have wandered over to the PPV specific section. I greatly appreciate all the responses and suggestions. A scanner, tuning device, Tech2 are all in the works.