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What are the ideal gears for 10bolt/700r4/33's???

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Bone85K5, Apr 8, 2003.

  1. Bone85K5

    Bone85K5 1/2 ton status

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    What are the ideal gears for 10bolt/700r4/33\'s???

    Any thoughts? I have a stock 10bolt rear, blazer is a 1985 that came with a 305 orginally. My transmission guys says a better guy might take some stress off of the 700r4. Im on the highway 85% of the time these days. The truck has 3.73's now by the way.

    Also, do i have to have the same exact gear ratio in the front as I do the back? I have been told that it would be ok as long as I am on slippery ground when in 4wd...nto sure if this makes sense so thought id ask here..
     
  2. Hossbaby50

    Hossbaby50 3/4 ton status

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    I say 4.10 for highway, and yes you do have to have matching gears front and rear if you ever plan to use 4x4.
     
  3. Silver84k5

    Silver84k5 1/2 ton status

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    if your in the snow then you could use 4wheel drive, but i dont know how it would perform, some mud racers acutally put lower gears in the front end to get the front tires to pull more in the mud....... but i wouldnt suggest tryin to use 4wd without matching gears F@R, its a recipe for Tcase disaster.

    4;10s or 3;73's.....
     
  4. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    I'll concur with Hoss on the gear recommendation with the 305. I ran 3.73 on 33's for about 4 years, I have a 350 and my K5 is on the road 99.9% of the time. It was okay, but I could of stepped up to 4.10 for the hills. It wasn't a dawg on the flats by any means, but the hills could be painful at times.

    As for the different gears, I have that same syndrome right now (I'm a gear higher in the front). I've wheeled a couple of times with it. On the dry dirt hillclimbs, it wasn't bad. Never had it in the mud, but tried to whup it up in the snow one time and that's the last time I attempt to do that. The gear difference on the snow just plan sucked butt. In the overall scheme of things though, it's a pain in the butt to wheel with a gear differential cause stuff is whining death and driving the thing is a lot harder.
     
  5. 88Silverado

    88Silverado 1/2 ton status

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  6. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    4.10 is ideal for fuel economy. If you EVER plan on going with a 35" tire, I'd get 4.88s.

    If it was my truck and I never planned on going bigger, I'd still get 4.56s. If I planned on going for 35s, I'd get 4.88s.

    I would not put your truck in 4wd with mis-matched gears.
     
  7. wrathORC

    wrathORC 1/2 ton status

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    If I were to buy new gears I'd buy 4.56s. However, once you get to 4.56 you're not talking about a lot of contact area between the ring and pinion. That makes it pretty easy to spit teeth off the ring gear. If you don't drive it like you stole it then you'll never have a problem.

    However, I'd be perfectly happy with 3.73s or 4.10s. If I were you I wouldn't bother with a gear change. Unless you have access to a pair of axles with 4.10s it isn't worth the gear change to 4.10s.

    NP208s don't like it when you run different gear ratios front to rear. It's pretty hard on them. Not to mention it's weird driving like that. In general, you need to keep ratios within 1% of each other. You also have to include tire diameter which is why most people that know better end up running different air pressure front to rear (I have 33lbs in the front and 28lbs in the rear right now).

    Anyway, if I were you I'd be happy. If she didn't like expressway speeds in overdrive I'd just drop it into third gear. You should have no problem with overdrive at highway speeds.
     
  8. Bone85K5

    Bone85K5 1/2 ton status

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    It does have a 350 in it, not the old 305. This 350 is very healthy and has plenty of power.
     
  9. rick88blaze

    rick88blaze 1/2 ton status

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    i gotta ask, why do you run different air pressure between front and rear? /forums/images/graemlins/confused.gif
     
  10. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    4.10.

    j
     
  11. wrathORC

    wrathORC 1/2 ton status

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    So I can get the tire diameter the same size. The idea is to get the same amount of sidewall squish front and rear. This keeps the tires wearing nicely and in the case of a 4x4 the transfer case really appreciates it. In my opinion, in the case of a 4x4, you want the circumference of a set of tires to be within 1.5" of each other.
     
  12. Thunder

    Thunder 3/4 ton status

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    I dont think regearing from 3.73 to 4.10 is worth the expense. You should not run 2 diferent gear ratios. For what it costs to have both axles regeared. You can build a pretty healthy engine. If you need more power. Headers,exhaust,cam,&intake will help a lot.An aftermarket trans cooler is also a must have.

    I have 3.73s 33" Mt tires and a mildly built 350/700r4 and have no problems with power in the hills. There are quite a few around here I live at 5000 ft elevation. I built my engine to put out a lot of torque at 2000 rpm (cruising speed in over drive for me). I also tow quite a bit. Having 3.73s has really been no problem for me.
     
  13. Bone85K5

    Bone85K5 1/2 ton status

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    I agree, after pricing new gears at the local drivetrain shop. I already have headers, duals, no cats, intake, carb and 2 aftermarket tranny coolers by the way.
     
  14. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    Yeah, keep towing. Sounds like a recipe for a quickly destroyed 700R4. Then again, that's why I ditched mine.
     
  15. Hustler

    Hustler 1/2 ton status

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    Depending on your engine, I would say 3.73 would be fine. That is what I have with 33" tall tires. I don't have a problem at all, but I do have a 383 stroker. I have lots of low end power.
     
  16. Thunder

    Thunder 3/4 ton status

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    Tim.
    My 89 K5 has been towing trailers since it was new (14 years). I have towed Travel trailers up to 22' no problem.I Haul wood out of the hills all summer. I tow my boat to the coast and back every summer(about 1300 miles round trip). I also have a Lead Foot /forums/images/graemlins/laugh.gif. I still have the orginal stock 700r4. It has never been rebuilt. I drop the pan every year and it is always clean and shows very little signs of wear. I know a few people that tow with 700s with way over 100K miles on them and still running strong.
    I imagine someday my tranny will give out. They dont last forever. But with proper care the 700 is a good tranny and will last a long time. I change the fluid often and run both a tranny cooler and engine oil cooler.
    I dont advocate towing big heavy trailers with them they weren't really built for that. But for general light/medium use. I think they are a good tranny.
     
  17. wrathORC

    wrathORC 1/2 ton status

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    700R4s are like fuel pumps, you never know how long it's going to last until it dies.

    My Grandparents had a 90 3/4 ton 2wd pickup. They bought it used with like 20,000 miles on it. They drove it and one day the odometer broke at 240,000 miles. They drove it until what they guessed was 290,000 miles at which time the frame broke behind the front tires.

    It was beat to death. Never taken care of. One time my Dad had the heads off because it wasn't "running right" to find that one valve had been burned so bad that it collapsed and got stuck inside the head. At that time, it had ~130,000 miles on it. He "repaired" it, put it back together, threw a high volume oil pump on it, and told them the motor was tired and wouldn't last much longer than 20,000 miles. The only reason we could figure out why it lasted so long was Slick 50. It still ran alright when parked but burned a quart of oil every 600 miles or so.

    It had a 700R4 transmission. Never once serviced.

    It hauled a 6 stall horse trailer with at least two harness racing horses in it most of its life. About 50% of the time it didn't even have trailer brakes. The truck outlasted two horse trailers (both rusted out). I think the truck went through 4 fuel pumps. It just goes to show some last and some don't.
     
  18. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    It probably had 4.10 gears, being a 3/4 ton, and short tires. That would be why it lasted, it was spinning enough to cool itself. That makes perfect sense.

    You're right. Everything wears out. But not having enough gear when you're towing doesn't WEAR out your transmission. It burns it up from getting too hot all the time. I'm not the only person that will tell you that 33" tires are too tall to tow something 4,000 lbs. or so with 3.73 gears. There's a reason that the factory doesn't gear trucks like that anymore. It doesn't last.

    I could go on and on about this, but you don't believe me, so I'll just let you go out and be stupid.

    Of course, I don't know anything. I only tow a 31' long trailer that weighs ~10,000 lbs. But of course I wouldn't know what gears or how tall of tires are ok in that instance...no, not at all.
     
  19. wrathORC

    wrathORC 1/2 ton status

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    3.73s and 245x75r16 if I remember correctly. It might have had 265s. They ran a lot of different tires over the years.

    What kills a 700R4 is the torque converter not being locked up. They tow just fine as long as you run third gear. Anyone that tows in fourth gear is a dumbass to put it nicely. A 700R4 is just as strong as a TH350, the only weak part is the heat problem generated by an unlocked torque converter.

    In essence, towing does wear out your transmission. It stresses the clutchpacks more. The more you're dragging the longer the clutches slip. I've seen quite a few discolored bands from morons towing in 4th gear. I've seen the entire contents of four 700R4s and they were all wore. Only one wasn't in a truck, it was out of a Camaro with 170k on it.


    I don't know why you chose me to reply to.
     
  20. 90K5

    90K5 1/2 ton status

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    Re: What are the ideal gears for 10bolt/700r4/33\'s???

    33's with 3.73's is pretty close to ideal...a 305 is not ideal...You'd probably be happier with the money you would spend on 4.10's then having the 4.10s cause there isnt much of a difference...and be happier putting that money towards a 350 /forums/images/graemlins/cool.gif
     

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