I installed a new third in my truck a couple weeks ago. I was figuring it would need bigger tires to kinda make it tolerable after I finished but I knew for sure the 3.31 stock ratio wasn't going to work for me. A travel trailer is in my near future, and I tow a small boat and load with motorcycles weekly.
Stock I was stalling on uphill starts EMPTY and smelling clutch when backing into my barely sloped driveway with a 1000 lbs. total trailer/boat combo. Not good.
I was stuck between 3.73, 3.90 and 4.10... I am glad I went to the lower ratio in my sites.
I'm happy to report the new 4.10 and stock tiny wheels/tires are just fine. In fact, my MPG have stayed the same. a tank of mixed driving and up to 80 MPH actual speeds netted 23.5 and 24.5 MPG. If I can manage to stay below 65 I'm sure that can go up a bit.
The engine feels like it has been set free. It (relatively) leaps forward now with a bit of throttle. It was struggling badly before.
Stalling on uphill starts is a thing of the past. I can release the clutch with no gas pedal and the truck walks away at idle. Throttle response is absolutely transformed, the thing pulls now. It feels like it lost 1500 lbs. off the bare truck.
First is slightly short, but unless you are rolling at least 5 MPH, second is just a skootch too tall to start in. So, first gear start, then shift to second after you are at least rolling. Highway speeds to 80 MPH cruise are smooth and quiet. It'll pull 5th gear cleanly at around 1500 RPM/40 MPH on semi flat roads.
Stock it could comfortably cruise at 50 MPH in THIRD GEAR!!!
My local mountain road downhill was a death ride dragging 3rd gear stock, it would soar to over 50 MPH easily requiring heavy foot braking. Second gear was too short, and it would rev to the moon. With the 4.10s it holds the truck perfectly at around 35 MPH.
In short, it cost me $1035 and 2 hours on my back and was worth every cent and bit of wrenching. Why this truck isn't stock with this ratio I can't understand.