Engine/Transmission (1998.5 - 2002) how to increase cruise speed

[jkidd]

I have a 4. 10 rr and 6spd and don't do much heavy towing (8,000 lbs and less)



I wanted to got faster than 70mph and still keep the rpms below 2000 so I don't kill the mileage. should I switch out my 265/75/16 for some 285 or 315, or put in a 3. 73 or 3. 54 in my dana 80?

 

[nps]

Tires are easier/cheaper than new gears.



You may find some members that want to swap you for your 4. 10s. Do you have limited slip, and are you 4x4?

 

[JWBoothe]

I bought 295/75/16 Toyo Open Countries. They look a hell of alot better, ride better and brought the RPMs down. They rub slightly at full lock.



80mph = 2050 RPM.



8% drop in RPM from stock.

 

[EricBu12]

To keep skinny and tall, I went to 19. 5" rims from Ricksons



These are skinnier and use the factory cap on the lugnuts.



245/70 R 19. 5" is the same diameter as a 285-16" ... but the tread width of a 265-16"



The tires are michelin "F" rated 12 ply Roll very good, nice deep tread (21/32nds) Should last 90K... .



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This is the difference between the stock 265-16E tire (left) and the 245/70R -19. 5" "F" tire. Notice the section width, the overall width is narrower.



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[bkroupa]

I shopped around & bought a low mileage used Dana 80 with 3. 54's & Limited slip.

After I installed it in the truck I sold the 4. 10 axle on Ebay for ~$30 less than I paid for the other one delivered . I did start out swapping to 285's on my 2wd truck which is a 10% RPM reduction, no real mpg reduction probrably because of the heavier tires & more rolling resistance. The 3. 54's are the best single improvement I've made to this truck. I get a solid 1. 5 mpg better on my normal commute & even more improvement on hwy trips. The noise reduction cruising down the hwy is wonderful. You can pass a string of cars without hitting the govenor (well before I did the 4k kit anyway). Unless you have a 4wd & can swing huge tires, go with the gears, you'll wonder why you waited.

 

[EricBu12]

Now you need to do this...



Go to products and select Tru-speed calibrator.



http://www.superlift.com/



I did this for my 19. 5" tires and on a straight stretch in the middle of the night, I was able to adjust it to within 100' in 13 miles... ... good enough I think... .