Within the next month I am lifting my 01 Silverado 6" and dropping 35s under it. Would a set of 4.10's front and rear get my power back to normal and not kill my tranny. I have a 4.8 and a 4L60e. Already done the cat back, cold air, and a super chip programmer.

 

I would go with 4.56 gears. Motive gear are what i have. I dont think 4.10 will do it.

 

At least 4.56.

 

that 4.8 is gonna need help with those tires. Id also do 4.56.

Derek

 

Thanks for the tech guys thats what I needed to hear. That little 4.8 is running sweet even with 75k on her, fixin to swap out all fluids to royal purple with the lift. Every little bit helps.

 

dont put rp in the diff. Just a reminder.
Derek

 

whats rp?

 

i think he means royal purple

 

my best friend's sierra was lifted w/ 35'' SSR's and 4.56's were perfect.

 

I think this was posted here once before, I thought it would be useful down the road. Hope who ever posted it doesn't mind the re-post. Good luck!




I found this interesting equation about how to get your truck running like it was designed to after you change tire/wheel sizes.

First determine your wheel diameter of your new and old tires.
If you don't feel like measuring or are unsure check out this site.

http://www.net-comber.com/tirecalc.html

My example:
Old tire size 235/75-16 = 29.88 inches
New tire size 275/55-20 = 31.91
Gear Ratio = 3.42

Step 1 [Old Tire Size]/[New Tire Size]*[Current Gear Ratio] = [New Gear Ratio]
29.88/31.91*3.42 = 3.20

So switching to 20's actually makes my 3.42 act like 3.20 (this sucks!!)

Step 2 [New Tire Size]/[Old Tire Size]*[Gear Ratio] = [New Gear Ratio]
31.91/29.88*3.42 = 3.65

So to get my truck back to factory optimized parameters I need to increase my gears to at leat 3.65 (3.73) to get to back to decent gas mileage