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gearset for 350/400/205 for 37s?

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obijuan

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im swapping trannies from a 700/208 to the 400/205 very soon. ive currently got 4.56 and 37s but im afraid that ill be screaming down the highway now that the trans has changed. im building some axles right now, so i have the choice of gears right now as i havent bought anything.

i was going to go 5.13s but probably not anymore, ideal tire size for offroad would be 40 inch boggers and most likely 37 inch hummer tires for the road. i never have made it over 70 really, swampers get a little bouncy lol.
where i find my tach when cruising it always read around 1800-2100 rpms at slow highway speeds. the truck likes it there and i would like to keep it around there for the highway.

what would my best option be for say 65 mph at 2200 max?
 
news to me:o and as of right now its still a daily driver, about 5 miles one way to work. other than that its 20 miles to the pits and back. thats about the only time i do drive it and its on the highway.
 
I know I found it accidently and have played with it alot for different hypothetical setups.

Just go to the Tech Tips section and its right in there
 
with 4.56 gears it should only drop 25 percent without the overdrive.so that would put you in the 2625 range with the 400.to get back to the same gearing as the overdrive you would have to put in 3.73 gears but that wouldseriously bring down your performance quite a bit.to keep you in the 2100 to 2400 range and still have adequate performance for wheeling 4.10 gears would get you a happy medium.i only have 35s on mine with 4.10 gears but if i had a bigger tire like you have it may feel a little bogged down.but that is the options you got.i personally would stick with the 4.56 you got and just go a lil slower.it would suck to lose that much power because of gearing issues and overeving the engine to get there.
 
carpeonnel said:
or.... go to a higher gear for highway and go doubler or lomax for your tcase:D
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psh i lol'ed

sounds like im just gonna make do with 4.56s with 37s right now and then 40 or 42 later. i dont have to take the highway anywhere round here, everything worth goin to is pretty much a back road.
 
I know that I can do nearly 3 grand on the highway in 3rd ( 1 to 1 ) with 4.56 and 35's , so 37's would drop that down a little bit .

I would stay where you are and keep it no more than 65-70 on the highway until you kill the 10 bolts , then upgrade and gear the 8 lugs you end up getting :thumb:
 
obijuan said:
psh i lol'ed

sounds like im just gonna make do with 4.56s with 37s right now and then 40 or 42 later. i dont have to take the highway anywhere round here, everything worth goin to is pretty much a back road.
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when you go to 40s that would drop your rpm to around 2400.42s would drop you into the 22-2300 range.and then you would still have adequate power to turn those big meats with the 4.56 gearing.
 
good! all i have really been doing is prepping for the future and gathering parts. im upgrading by necessity, my favorite kind!
 
My buddy in college used to pimp his 70 Nova at 4000 RPM for hours at a time. The TH400 is a horrbile trans for wheeling. First gear sucks. Get a SM465 and be happy, or grow a money tree.
 
I have 4:10's with 37's and a TH400 with no real issues it will do 80 all day, more comfortable at around 70, not a clue what RPM's I am running.
 
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