Differential gear change

[97audia4]

Ill be following this, same dilemma with my yukon Denali.

 

[thompsoj22]

Honestly, i just went through this same issue with our last tahoe. it had the 4.8 with 3.42 and we pull 4,100lb travel trailer. This configuration is extremely underpowered/geared so i installed a 3.73 from the salvage yard for $375. It increased the rpm by a little less than 400 and made towing "different" with hills/headwind being more doable but not easy/effortless. i know it is apples to oranges but that is why we got the 08 denali 6.2 xl1500 which has the 3.42. It tows our trailer much better, i keep it in manual mode and limit it to 5th. The tow/haul feature i use once im at speed as it seems to allow me to hold a gear longer without downshifting. i dont use it from a dead stop as it seems "confused" from an rpm standpoint getting up to speed. My opinion is to "not" go through the cost of changing ratios on the vehicle simply to tow your boat, slow down, put in a movie for the kids and get there in comfort. 3.08 is absolutely not a towing gear ratio for anything other than a diesel engine, but you only have to accept it while towing, other than that it works perfectly.

 

[K2 Kaiju]

Look at this chart. The 1st gear on the 6speed is so low, it actually makes the 3.08 closer to 4.11 gears on the old 4 speed.

Tow haul will hold rpms, so the gear ratio really wont change druving at speed much...

Sent from my SM-G950U using Tapatalk

 

[Nashoba]

Last time I changed out a rear diff was on my 2004 Silverado Extended Cab with a 4.8L and 4 speed auto in it. I went from 3:42 to 4:10 gears instead of going with a nitrous injection setup as I normally would have. I was very pleased with it and the cost was about $1K, and I got to keep the original pumpkin. The improvement was phenomenal. Over my normal commute, the downshifts by the cruise control system dropped by 70% while my mileage dropped only 1.25 mpg, and my engine was not subjected to the additional stress of the NOS when I wanted to pass on the two lane roads of southeastern Oklahoma. I did it all after the warranty was out so I did not worry about that. I'd like to do it to my 2015 Silverado 4X4 but I have the 100,000 mile power train warranty and as of today have only 11,211 miles on it.

If you have the funds, you might consider an under/over drive unit that mounts where the tail shaft in on automatic transmissions. It used to be really popular for turning a 4 speed or six speed into an 8 or 12 speed automatic. The cost was about $2,750 and it was a bullet-proof unit that some even used for the drag strip. I just never could pull the trigger and get one. It just bolted on but you had to get a shortened drive shaft. If you are interested, I will see if I can find some data on it for you.

 

[Chrismnj]

isn't a gear ratio determined by your tire size? any way what is a stock tahoe tire size in inches?

 

[Jeremy05]

Looking at that chart it does not appear that the 3.42 is going to make a big difference in 5th & 6th gear. My Yukon does not have any problems pulling the boat out of the water or pulling a low speeds. I was hoping that changing the gears would make it easier to pull at highway speeds. I'm staring to think that it would be better to just save the $2K and not mess with the gear change.

 

[swathdiver]

Looking at that chart it does not appear that the 3.42 is going to make a big difference in 5th & 6th gear. My Yukon does not have any problems pulling the boat out of the water or pulling a low speeds. I was hoping that changing the gears would make it easier to pull at highway speeds. I'm staring to think that it would be better to just save the $2K and not mess with the gear change.

Try towing with it as is first and then decide.

 

[thompsoj22]

Looking at that chart it does not appear that the 3.42 is going to make a big difference in 5th & 6th gear. My Yukon does not have any problems pulling the boat out of the water or pulling a low speeds. I was hoping that changing the gears would make it easier to pull at highway speeds. I'm staring to think that it would be better to just save the $2K and not mess with the gear change.

Thats the right decision, also another factor in your favor is the aerodynamic's of the boat are much better than the "square box" travel trailer. The biggest obstacle/force when towing is the wind, head wind being the hardest to overcome, side wind which add's the "white knuckle" ambiance to the trip and the "blessed" tail wind which will have you staring at your speedo wondering if the trailer is still behind you. one thing is for sure "10-MPG" but hey the kids or other passengers are watching a movie or listening to serius at the same time in total comfort!

 

[Jeremy05]

I was browsing around and the price of the actual gears. Does it make any sense that the AAM gears are cheaper than the Yukon gears? The AAM gears for the front are around $220 and the Yukon gears are $368. Is there something that I’m missing. Does not seem right that the OE gears are cheaper. Also, does the carrier have to be changed going from 3.08 to 3.42 or 3.73?

AAM gears link.
https://www.drivetrainamerica.com/40093541-gm-8-25-ifs-3-42-aam-oe-ring-pinion-gear-set/

Yukon gears link
https://www.randysworldwide.com/product/yg-gm8-25-342r/

 

[Mickey_7106]

Not to hijack but i was wondering if 4.10 gears fit in a stock 3.42 case for my 4x4

I was browsing around and the price of the actual gears. Does it make any sense that the AAM gears are cheaper than the Yukon gears? The AAM gears for the front are around $220 and the Yukon gears are $368. Is there something that I’m missing. Does not seem right that the OE gears are cheaper. Also, does the carrier have to be changed going from 3.08 to 3.42 or 3.73?

AAM gears link.
https://www.drivetrainamerica.com/40093541-gm-8-25-ifs-3-42-aam-oe-ring-pinion-gear-set/

Yukon gears link
https://www.randysworldwide.com/product/yg-gm8-25-342r/