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Discussion Starter #1
My truck has 3.55 gears in it and i was thinking about going to 3.73s. anybody done this or got any opinions?

thanks, austin
 

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I got 3.73s..... but then put 35s on them so should be around 3.55 with tire size change.
 

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355's... yuck. Doggy gears to tow with. These obs trucks do great with 4.10's.
 

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I love the 3.73 ratio on my truck behind a 6 speed, it is still plenty low in granny gear to pull anything... and is right around 2 grand at 65mph which is still a decent spot for mileage, and high enough rpms for towing. I still have stock tires though.
 

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Ya a 6spd would be fine with 373's since the tranny gearing is so low.. but our 5spds and e4od's... no way.
 

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I can tell u that my truck does just fine with 3.73s and towing does just fine even with 35s. If i trusted my egt gauge it would do even better but i refused to take it over 1000* its in the right spot just a cheep gauge i put in so i knew where i was at.

3.73 is the best gear out there imo for any truck that does any towing. If all u do it tow every day all day then 410s would be needed.
 

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Discussion Starter #7
yeah i do some towing but not everyday and i dont want it screaming going down the highway so i think 3.73s would be good. i hate to have to ask this but what front axle do i have? its the twin i-beam but i havent been able to find gears for it.
 

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I've got 4.10's and I dont scream down the highway w/ my 35's. Look at your door jamb or on the diff... it will tell you the axle ratio.
 

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Discussion Starter #9
yeah i've got the ratio i meant like my rear is a ford 10.25 differential but i dont know what the front axle is called. I need to know which gears to buy so that they'll fit
 

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Its a Dana 50
 

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I've got 4.10's and I dont scream down the highway w/ my 35's. Look at your door jamb or on the diff... it will tell you the axle ratio.
Which once u do the math u will find out that u come out the being geared a little higher then a 3.73... so to till this guy that the best gears for his truck are 4.10s when he had pretty close to stock size tires is false and that 3.73s are dogs for towing unless behind a zf6 but never for an r4 or e4od?? Im confused now? Since u kinda do have 3.73s
 

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Which once u do the math u will find out that u come out the being geared a little higher then a 3.73... so to till this guy that the best gears for his truck are 4.10s when he had pretty close to stock size tires is false and that 3.73s are dogs for towing unless behind a zf6 but never for an r4 or e4od?? Im confused now? Since u kinda do have 3.73s
I dont think 4.10's w/ 35's is quite 3.73's.. but if you put 35's onto 3.73's and try doing any work, your really gonna be hurting.

And fwiw, trying to get a load moving w/ my 35's sucks balls. Once its moving though it's got plenty of power.
 

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I have a d50 in my garage on the floor with 4:10's if your interested, needs a spindle lol but I have 4:10's on mine at cruise just over 2 k rpm on the hwy at 75ish mph I have no problems moving any load, excursion, minivan, f150's gooseneck trailers loads of power
 

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something people arent telling you - is that if you go down to 4:10's you will NEVER see 85/90 mph again. i have a 2wd dually with 4:10's. these gears are really meant for hauling, and its not real great on the highway. i also had a gas f350 with 3:73's and it could cruise on the highway at 90 without even trying. my 4:10's cruise at the low 70's range. anything more than that and its pushing the truck more than i feel comfortable with. can i hit 80? yea - but i feel like im kicking the hell out of it, and i would never maintain that speed with these gears.
 

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something people arent telling you - is that if you go down to 4:10's you will NEVER see 85/90 mph again. i have a 2wd dually with 4:10's. these gears are really meant for hauling, and its not real great on the highway. i also had a gas f350 with 3:73's and it could cruise on the highway at 90 without even trying. my 4:10's cruise at the low 70's range. anything more than that and its pushing the truck more than i feel comfortable with. can i hit 80? yea - but i feel like im kicking the hell out of it, and i would never maintain that speed with these gears.
If he is going to run a 315 or 35" tire then the 410 gears are going to be comparable to 3:73's
 

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something people arent telling you - is that if you go down to 4:10's you will NEVER see 85/90 mph again. i have a 2wd dually with 4:10's. these gears are really meant for hauling, and its not real great on the highway. i also had a gas f350 with 3:73's and it could cruise on the highway at 90 without even trying. my 4:10's cruise at the low 70's range. anything more than that and its pushing the truck more than i feel comfortable with. can i hit 80? yea - but i feel like im kicking the hell out of it, and i would never maintain that speed with these gears.
Not true. When I had 33's on my truck with 4.10's I ran it up to 120mph. Lots and lots of people on this forum have found 120mph with their 4.10 geared OBS truck with stock tires.
 

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Is that truck still for sale? You're kinda counter advertising. It sounds like it's been run awfully hard. With 3.55's and 33's I'm at redline at 105 mph. 120 pushes that up to around 37-3800.
 

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Is that truck still for sale? You're kinda counter advertising. It sounds like it's been run awfully hard. With 3.55's and 33's I'm at redline at 105 mph. 120 pushes that up to around 37-3800.
No it's not for sale. It sounds like its been ran awfully hard because I've had it going 120? Jeez... wonder what you'd say if you saw it towing some 15k lb farm tractors or 30k lbs of hay.
 
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