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I regeared my maga cab to 3.73 my tires size is 295-70-18 which is two sizes bigger than stock. After going over the gear ratio Calculator I’m running almost 100 rpm higher than stock. My truck has 36k on it with the 3.42 and 305-70-18. My question is how long does it take for the computer to relearn with the new gears or do I need to buy a programmer.
 

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I regeared my maga cab to 3.73 my tires size is 295-70-18 which is two sizes bigger than stock. After going over the gear ratio Calculator I’m running almost 100 rpm higher than stock. My truck has 36k on it with the 3.42 and 305-70-18. My question is how long does it take for the computer to relearn with the new gears or do I need to buy a programmer.
I used the aev procal


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You really need a Pro Cal due to the pulse difference between the ABS and the trans.
 

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AlfaOBD can program the new axle ratio and tire size into the body control module.

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How you liking the 3.73 so far? I've thought about it myself (3.42 now). Not a big change but with 35's I figured it would put it in the "sweet" spot.

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How you liking the 3.73 so far? I've thought about it myself (3.42 now). Not a big change but with 35's I figured it would put it in the "sweet" spot.

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How you liking the 3.73 so far? I've thought about it myself (3.42 now). Not a big change but with 35's I figured it would put it in the "sweet" spot.

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So far I do it gave me about 150 more rpms. I only have drove it about 2 hundred miles so far. The motor isn’t lugging like it was. I’ll keep you posted
 

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My 11’ has 35’s and 3.73’s, and at 75 mph, I’m turning 16-1700 rpms with the 68rfe trans.
 

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I regeared my maga cab to 3.73 my tires size is 295-70-18 which is two sizes bigger than stock. After going over the gear ratio Calculator I’m running almost 100 rpm higher than stock. My truck has 36k on it with the 3.42 and 305-70-18. My question is how long does it take for the computer to relearn with the new gears or do I need to buy a programmer.
The truck’s computers don’t need to know what gear ratio you changed to. It’s the tire size that is set in the BCM that matters, and will correct your speed and shift points. Skip all the one trick pony programmers and just get AlfaOBD, since it’s a far more capable tool.
 
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