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Old 08-30-2002, 12:17 PM   #1
dubie
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Would there be any benefit to this??

I am looking at swapping out the original 3 speed for a SM465. This tranny has the granny low speed, and I wanted to know if it would a damn bit of difference in driving. Seems to me, I might be better off stickin with my 3 speed.
Need info guys.
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Old 08-30-2002, 12:36 PM   #2
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Why are you considering the swap. I have the 4 spd w/granny, and don't like the fact I get around 8 mpg, and can't go very fast. I am replacing the rear differential gears. That way i keep the original Tranny, and get the benefits of having a cruiser.
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Old 08-30-2002, 12:42 PM   #3
O'l Buck
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the only benefit to the 4 speed would be the low gear, for taking off easier and for pulling a trailer if you do that at all......the high gear will be the same....1:1 is 1:1, don't matter what tranny you have.
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Old 08-30-2002, 12:45 PM   #4
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The only gear you'd gain by that swap is a gear that is not used in everyday driving. It's just for towing/hauling/stump pulling. Sure, it comes in handy to have starting from a standstill on a hill and stuff like that but you can do without it just fine. The other three gears are pretty close to same ratios. Drive is drive is 1:1, so there's no difference in highways RPMs.

What you do get is a floor shifter, which I think is pretty cool and worth something.
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Old 08-30-2002, 01:35 PM   #5
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I like my CH465. I do use the granny gear once and a while for heavy hauling or parking if I just want to let the engine idle and creap along. I've heard the 465 is alot heavier than the 3 speeds. I don't know if it'd be worth the effort unless you have the truck torn apart anyway.
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Old 08-30-2002, 01:54 PM   #6
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Factory 4 speed trucks came with a high hump cab. You might have to "modify" your floor pan for clearance issues. The granny gear is the next best thing to 4 wheel drive since it lets you very closely modulate power and wheel spin. When combined with limited slip, lets you drag a boat up a ramp with virtually zero wheel slippage.
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Old 08-30-2002, 02:29 PM   #7
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OK, lets just scrap the whole 4 speed question and move onto another.
What is the best rear end gear ratio for a daily driver. It will be driven on the highway at 100 kph and around town. I currently have 3:07 with the inline 6 and 3 spd. I don't have a tach on the truck but would almost be afraid to see how high the rpm is at highway speed. The engine will be a mildly built 350.
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Old 08-30-2002, 02:35 PM   #8
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Tim,

For daily driving without an overdrive tranny the 3.07 is probably the best with a mild V8. A 3.73 is alot more fun though and if you get an overdrive tranny the 3.73 is real nice. If your truck came as a 6 cyl and still has the original diff in place I'd bet it is a 3.73. If you want to put another set of gears in an existing diff a 3.42 would be a good compromise.
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Old 08-30-2002, 03:00 PM   #9
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It's more than just the weight though, there is also mechanical leverage there too.
If it is mostly freeway driving, tall tires will help, but, they will hurt your take off too though.
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Old 08-30-2002, 03:38 PM   #10
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The only highway travel that will be done , is to the cabin and back. Which is only about 10 miles away. The rest of the time will be spent cruising around. The tires I have on there are 235 75 R15 all seasons. I am still going to use this truck for hauling anything I need , and will be staying with actual truck tires. I like the look of low profile tires, but for the purpose my truck is used for, I don't think they would hold up. Thanks for all the replies guys
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Old 08-30-2002, 04:49 PM   #11
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The 3.42 would be the best probably, but they are not very common... With such short road trips, I would go for the 3.73 and 28-30" tall tires. I have 265 75 16 on my truck with 3.54 gears. They are 30.5" tall, about the same as a 31 10.5 15. More gear around town might actually help your mileage.
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