Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Alternative to regearing?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by MudFrog, Dec 17, 2000.

  1. MudFrog

    MudFrog 1/2 ton status

    Joined:
    Feb 23, 2000
    Posts:
    3,236
    Likes Received:
    0
    Location:
    Daleville, Va
    I was reading a 4x4 mag, and I got to thinking. Instead of regearing the axles when adding bigger tires, could you swap in a differen't transfer case? Take for instance the Atlas II gear drivin unit. I know the gear range is much much lower on this transfer case. So theoritically couldn't you swap in one of these instead of lowering the axle gear ratio? I'm not gonna try it, just wanted to see if anyone agrees with me.

    89 K5 Silverado
    http://mudfrog.coloradok5.com
     
  2. SANDMANPHIL

    SANDMANPHIL Newbie

    Joined:
    Nov 16, 2000
    Posts:
    4
    Likes Received:
    0
    Re: Alternate to regearing?

    WELL I DONT KNOW ABOUT THE TRANSFER CASE BUT WHEN HE NEEDED TO REGEAR HE JUST SLAPPED ON A WHIPPLE SUPERCHARGER. HAHA. ITS NO BIG THING FOR HIM THOUGH, HE WORKS FOR WHIPPLE SO HE GETS THEM FOR FREE. LUCKY BASTARD HUH? ITS ALL GOOD THOUGH CUZ HE'LL WORK ME A FAT DEAL TOO. CYA
     
  3. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

    Joined:
    Feb 17, 2000
    Posts:
    7,385
    Likes Received:
    0
    Location:
    Atlanta
    Re: Alternate to regearing?

    The point of Re gearing is as much to do with the street as it is on the trail. If it were a trail only vehicle you could run 8.20 gears and a briggs and straton engine. It would do great on the trail but would not exceed 25mph. Regearing gets the engine back in it's correct operating range for both power and fuel economy. The extra low case is only going to solve the problem on the trail.

    Diging it in the dirt with my K5's
    Grim-Reaper
    http://grimsk5s.coloradok5.com/
     
  4. Stephen

    Stephen 1/2 ton status Moderator Vendor

    Joined:
    Sep 15, 2000
    Posts:
    4,227
    Likes Received:
    142
    Location:
    Carbondale Colorado
    Re: Alternate to regearing?

    Transfer case gears are a good place to look for more power and versatility. On the trail what we're looking for is torque at the tires, right? There's only one place for it to come from and that's the motor, then multiply it by the various gear sets. If you want (just for the sake of round numbers) 20K ft-lb of torque spread between the tires, there's 2 ways to go, motor or gears. You could have a motor putting out 200 ft-lbs and 100:1 gearing, or a motor putting out 400 ft-lbs and 50:1 gearing. Ever rock crawl with a Toyota? once the 4 popper has 150:1 or deeper gears, they go about anywhere, but without deep gears, you might as well get out and walk. Now, pros and cons of the two ways to create torque:
    motor:
    pro-you can get a higher speed range without shifting up or down. Example, if you have the 400 lb ft at idle, you can go over creepy stuff at 600 rpms, then get on it and really be hauling by the time you reach 5 grand. But, most motors aren't that controllable in the low rpms.
    pro-you get to go fast on the highway too
    con-may be more expensive than t-case gearing, depending on your situation

    gears:
    pro-probably cheaper than a new motor
    pro-the motor is always in a better rpm range. what the big block is doing at 600 rpm, you'll do at 1200 rpm and have an easier time because you can go slower without killing the motor or frying your auto trans with converter heat.
    pro-you can use "highway" gears and still make it work offroad. With low t-case gears, you'll gear the diffs to work on the street, or if you don't use it on the street, you can just use a cheaper, or stronger gearset. We've seen pretty effective rigs with 4:1 Tcase gears with 44" tires and 4.10 axle gears. Try that without low tcase gears! One early K5 had 3.73's, a Doubler and 35's and did well in rocky trails and still ran out on the highway very nicely.
    con-you may not have the power you need on the highway in high range.

    Solution: build a mild big block and use a low geared t-case! That way you get it all!

    As for gearing in mud, we've had customers use a Doubler in mud racing and really like it because it gives some choice in gear for different tire classes and different conditions.

    [​IMG]
    SW-ORD
     
  5. MudFrog

    MudFrog 1/2 ton status

    Joined:
    Feb 23, 2000
    Posts:
    3,236
    Likes Received:
    0
    Location:
    Daleville, Va
    Re: Alternate to regearing?

    So whats the difference in the doubler and most other transfer casses's?

    89 K5 Silverado
    http://mudfrog.coloradok5.com
     
  6. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

    Joined:
    Feb 17, 2000
    Posts:
    7,385
    Likes Received:
    0
    Location:
    Atlanta
    Re: Alternate to regearing?

    The Doubler gives you 2 choices for low. 2:1 or 3.96:1. Lets you choose how much reduction for the terrain. most of the time 2:1 is more then enough but lots of times the extra reduction is really nice.
    Now let me point out that there are a lot of variables here. I love the Doubler set up ORD sells but even though my truck is a trail only rig it still has to get to the trail (2 hours) and as such it still gets 80% of it miles on the street.
    That said here is the point. If you got 3.73 gears then yeah the doubler will make life great. The truck will be acceptible on the street with 33's. But you have 3.08 gears and 35 inch tires your going to hate life on the street. My truck has a OK motor but no hot rod and with 3.08 gears it can't get out of it's own way on 32's. My plan is 4.11's and 35's and when I can afford it a Doubler.
    You need to figure out what gears you have and decide on a tires size first and go from there.

    Diging it in the dirt with my K5's
    Grim-Reaper
    http://grimsk5s.coloradok5.com/
     
  7. AZK5

    AZK5 1/2 ton status

    Joined:
    Feb 22, 2000
    Posts:
    448
    Likes Received:
    0
    Location:
    Chandler, AZ
    Re: Alternate to regearing?

    There is a problem with running a doubler without changing the axle gears. When you're running a 4:1 transfercase gear instead of a 2:1 your driveshafts, yokes, and pinions see up to twice the torque they used to. Changing the axle gears reduces the torque that the driveshafts, yoke, and pinions are subject to. The axles will see all the torque that is going to each tire. The torque applied is still limited by how much traction that is available to the tires.
    Putting a bigger motor in front of the transmission and transfercase just puts a bigger load on the driveline. It depends on what your going to do with your K5. If you're doing highspeed sand/mud go with a big motor and axle gears. If you're rock crawling go with a small motor, transfercase gears (doubler), and axle gears.
    CB
     
  8. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    Re: Alternate to regearing?

    Hey SandManPhil, those Whipple Chargers looks like the cats meow. But at $3500, I'd just go ahead and put the cash towards a new 502 or something. Can your friendwork out a good-buddy price for the CK5 crowd? My wifes '94 350 powered Suburban could really use some help here in the Rockies! [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    http://ThunderTruck.ColoradoK5.com
     
  9. 6.2Blazer

    6.2Blazer 1/2 ton status

    Joined:
    Feb 24, 2000
    Posts:
    4,675
    Likes Received:
    26
    Location:
    Ohio
    Re: Alternate to regearing?

    I think the biggest disadvantage to most of the low gear t-cases, as already mentioned, is that they don't do anything for the high range reduction. The one exception are the low geared kits for the Suzuki Samurai's which offer a super low geared low range (around 4 or 5:1), plus a small reduction in high range also (I'm thinking it's around 1.2:1). In this case, the 1.2:1 would make stock 3.73 gears act close to 4.56 gears in high range and give the best of both worlds.......good power on the highway and super low gears on the trail, all for one "low" price.
     
  10. MudFrog

    MudFrog 1/2 ton status

    Joined:
    Feb 23, 2000
    Posts:
    3,236
    Likes Received:
    0
    Location:
    Daleville, Va
    Re: Alternate to regearing?

    The doubler sounds pretty sweet. Anybody actually using one? Also is it gear or chain drivin?

    89 K5 Silverado
    http://mudfrog.coloradok5.com
     
  11. blazer72

    blazer72 1/2 ton status

    Joined:
    Apr 13, 2000
    Posts:
    939
    Likes Received:
    0
    Location:
    KCMO
    Re: Alternate to regearing?

    There are a lot of us useing them and there great, As grim said I have 2 rang's to use most of the time its the normal 2 to 1 but at times when I really need the tork or want to keep the speed down I use the 4 to 1 range. Its made up from a NP203 range box and a NP205 Tcase with alot of help from ORD. As for be hard on the drive shaft and gears It s but no more so than the other way you can do this. Beside it hard to get 102 to 1 with just new axels gears!

    I understand the jeep thing I drive a BLAZER!!

    Ken
     
  12. Blazer_Boy

    Blazer_Boy 1/2 ton status

    Joined:
    Dec 16, 2000
    Posts:
    1,669
    Likes Received:
    0
    Location:
    Sioux City, IA, USA
    Just take those dozen or so bolts out and throw in some new gears. You always see people swapping engines but not many want to touch the transfer case because its a good unit.
     
  13. MudFrog

    MudFrog 1/2 ton status

    Joined:
    Feb 23, 2000
    Posts:
    3,236
    Likes Received:
    0
    Location:
    Daleville, Va
    I'm paranoid about changing the gears, and I don't wanna pay $600 to have it done. I've heard to many horror stories about someone trying to change the gears and end up screwing something up.

    89 K5 Silverado
    http://mudfrog.coloradok5.com
     

Share This Page