Also make note of your in town milage also before swap.

 

Looks like the prices for the 3.21, 3.55, & 3.92 have gone up recently but you can still get the 4.10 for $1270.

http://www.trademotion.com/partlocat...layCatalogid=0

 

Over the past two weeks my in town avg has been 14.7. This is after an oil change to Rotella full synth and a K&N drop in. On the trip to my sister inlaws house last night (60 miles) @ 68 mph my MPG was 23.1 (on 87oct). Leaving now for Orlando with about 425m to go.

23 is pretty damn good.

 

Cruise set and out on the road non stop, you will get 24.? ,the 3:21's are crazy once you are out on the open road , let us know, i have those gears and KNOW what they do, when I posted my MPG when i first got on this forum, I was nearly crucified, for showing the EVIC on the highway, I hand calculated and MY evic is within 1 MPG, 23 is DAMM good, in my book for a CREW CAB loaded with 4 people on 20's , little did some know it was true.........since the lift and tires that hasnt happened again.

 

Reading about these gear ration, 3.21, 3.92 etc. What exactly those all this mean. Is one better the the other one. Should I thing about changing to make my truck run better? Can I get some insight. One more thing, if anybody as an idea, because the dealer does'nt. When I come to a full stop (i.e. stop sign / light) after a second or two, it's like the feeling of getting a slight kick under the seat. I'm not sure if it is transmission, which I don't think because I'm at a full stopped, or could it be the engine "bucking"??? (could find another word for it). Same thing happened a few times backing up. WEIRD!!! Thanks

 

It is most likely the ABS (Anti-Lock Braking System) releasing the rear brakes as the wheel rotation completely stops.

 

Three things effect the final drive ratio:

1. The engine crankshaft to transmission output ratio.
2. The drive shaft to axle gear ratio.
3. The tire height to axle rotation ratio.

When you change any one of the three; you "effectively" change the "final drive ratio".

When you change to a higher ratio (3.21) it is the equivalent of shifting the transmission to a higher gear in terms of torque and/or acceleration performance.

When you change to a higher ratio (3.92) it is the equivalent of shifting the transmission to a lower gear in terms of torque and/or acceleration performance.

 

I have 3:92s and the best so far - on the road is 19.2 mpg. I only have about 3,500 miles on it so far and drive moderately, until I pass someone. I don't like to hang out in the left lane (on a two lane) when passing so I get it over with fast.

 

Do you know what all comes on that?

 

Thanks for the reply. Couple more questions; 1. My truck seems to have a attitude, it seems to do it one day not the next. What's the deal. 2. Should there be an adjustment made?