Who has changed their 3.08 gears?

[jz57]

Take a look at your Tahoe's glove box cover, the build sheet shout be there. Most Tahoe PPV has GT4, 3.73 gear ratio and G80 LIMITED SLIP differential gear.

I have a 2014 Tahoe PPV with 3.08 gears. I am thinking about changing them out to 3.42 or 3.73's.

I am looking for a little quicker acceleration from a stop. I do not race my Tahoe but it is a slug accelerating from a stop light. I feel like I have to mash the gas peddle just to get it to move. I do not tow with it. I am just looking for better drive-ability.

Has anyone done this? If so how did it affect acceleration? Also how bad did it affect MPG's? What RPM's are you running at 80mph? Did you need anything other than the ring and pinion? Also how did you change the ecm for the gears? Will a tech II handle that?

I am not looking for a tuner at the moment. I still have 3 years on my power train warranty and I do not want to void it. After my warranty is up I will look into a tune.

 

[K2 Kaiju]

Super old thread, but I changed my gears on my 2011 2wd LS from 3.08 to 3.42 to tow my boat (I also added a truetrac LSD). The final drive on the 6speed/3.42 is lower than 4speed/4.10 combo (13.8 vs. 12.5), so for stock tires 3.42 is plenty for jerking out a boat...

Having driven both - I think the 3.08s are not as bad as people make them out to be. I actually might like the 3.08 1st gear (12.4) a tiny bit better for regular street driving (it is almost exactly what the 4.10s are with the 4 speed: 12.5) because the shift wasn't as quick to second allowing you to get up a little more speed before the shift. The problem is the gap between 1st and 2nd and throttle response/torque management. I you reset ECM and drive full throttle everywhere for a few days, you will notice a better response as your engine "learns" your driving style; a tune fixes both issues instantly which is why people feel such an improvement without a gear swap. I did notice about a 25 mile drop per tank after I switched to 3.42s. I wouldn't do 3.73 on stock tires...

 

[thirdcoast]

Specs on PPV from GM

2016 TAHOE 2WD POLICE PACKAGE 9C1
1. E85 is 85% ethanol and 15% gasoline. STANDARD 9C1 CHASSIS FEATURES AIR CLEANER High-capacity ALTERNATOR 170-amp high output with idle boost based on battery energy level (see specifications page for description) AXLE 3.08 Ratio with heavy-duty locking differential.

I suspect they do this to get the higher MPH with the stock engine.. PPV's never tow that I know of so don't need the lower gear.

As far as towing, with the newer vehicles, 4.10:1 might be fine with the .67 OD, but in my 07 Sierra with the Max Towing Package, I have 3.73:1 gears with the 4L70 Tranny. I pull up to 10K occasionally and 6-8K on a regular basis. Does well and gets 10-12 MPG at 70 with the 6-8K load. 130,000 miles and never had a problem with it..

TC

 

[Yukon John]

What RPM's are you running at 80mph?

FYI...my 2016 Yukon with 3:42's is 2000 RPM at 80 MPH...2400 at 100 MPH...it doesn't stay in 6th at 120 so it jumps a bit to 3200 RPM. Hope this helps.

 

[kronus]

Just adding that I can confirm my '12 PPV has 3.08's as indicated by the window sticker.

 

[Ryno21]

With the 6-speed I don't think I'd go above 3.73. I own a Sierra with the 4 speed and 3.73, tows pretty well if you don't tow anything huge. 3.43 would probably be ok. I also have a Tahoe with 3.73 rear and the 6.0/6l90 combo from a suburban. Tows like a beast. I'd say first gear is a little too low for a daily driver, but it gets off the line quickly.

It all depends on what you're looking for.