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Does anyone have any info on what happens when you change the gear size?

Hmmm,


Has anyone changed the gears on there truck?

you will have a different gear ratio if you change the gearshttp://www.dieselplace.com/forum/smileys/HiHi.gif

Funny GUY

their they're there, I have not heard of anyone running anything bigger in the Alli. Hoot knows.

Well, its not the Alli that Im worried about. The local Whiplash shop has an 8.1 with the Alli sitting behind it with 4.56 gears and 44" tires and a whole bunch of other garbage considering what is running the truck. They siad that it made a good difference for the gasser, but I dont know anyone thats done it with the diesel yet. Oh well, guess Ill just do it and see what happens. It will only cost 900 to change everything back, if it so horrible. I know it makes a difference with the old 6.2ltre diesel, got a big K-5 with 40s underneath it. When I changed those gears from the 3.73 to the 4.56 I got more power and the gas mileage shot up to 17 in town and about 22 at 65mph. Its definetely made a huge difference in the gas trucks Ive done. Anyway...

I would say with some big tires like mentioned above, it would be benificial, I dont know the calculation factor, but you will retain somewhat stock roll out ratio if putting in larger gears with large tires.


in my 85 chevy, 35" tire with 3.73 was close to 28" tire with 3.08's.. So, in essence, I still had 3.08 gears. SHoulda went to 4.56 gears with the big tires so that would make it fee like 28's with 3.73http://www.dieselplace.com/forum/smileys/Confused.gif

If you go to http://www.intercotire.com/html/tire-change.htm they have calculators of all kinds. With the 35" tires and and starting with 3.73 and 245/75/16 the change is the equivalent of having the 245/75/16 tires and a gear size of 3.25. With the 35" tires to retain the stock ratio I would need 4.28 gears. The highest they rocommend is 3.9 and the lowest is 4.67. So I figure with 4.10 gearsI would stay beneath the stock ratio, but would be closer, which would improve "take off" time. With a gas engine I would bet my life that this would improve fuel economy too, but I just dont know with this diesel. But like I siad, Im gonna just do it and suffer the consequences. I just wanted to see if anyone had done it and had experience with it. Gosh this stuff can be a head ache, some times I wish I would have just bought a chopper. Of course the chopper wont pull the boat, but I can work around that. http://www.dieselplace.com/forum/smileys/Geek.gif

in my 85 chevy, 35" tire with 3.73 was close to 28" tire with 3.08's.. So, in essence, I still had 3.08 gears. SHoulda went to 4.56 gears with the big tires so that would make it fee like 28's with 3.73http://www.dieselplace.com/forum/smileys/Confused.gif





I would seriously recommend the 4.56 gears in my first Blazer, which was gas, I had 35" tires and 4.10 and it was allright. Then when my dad got the diesel blazer we had them put 4.56 gears in both of them at the same time and the 4.56 gears made a significant difference in performance and mileage.