Milemarker

[SixShooter]

What is a Milemarker Select drive I saw it in someone's sig and was wondering what that is exactly?

 

[dmurdock]

basically (i think) a coupler which installs between the transfer case and front axle allowing you to stay in 4wd all the time... Here's a quote from their website: (i just searched for milemarker select drive at altavista's site and found it)

"MileMarker has developed a powerful, full time all wheel drive system. Selective Drive is not an after market conventional viscous coupler. It's a new technologically advanced system that offers full time power to the total drive train with both front and rear tires pulling and pushing all the time. For traveling up and down hills, snow, ice or dry pavement. Now all four wheels deliver refined pavement manners and improved handling on all road conditions. With Selective Drive installed, you can pull your transfer case lever into 4WD and leave it there, because Selective Drive alleviates any drive line binding on dry pavement. You'll have the added security of full-time power to all four wheels on dry, wet, snowy or icy roadways, and you can still shift into 2WD as needed. The Selective Drive unit mounts between the transfer case and front drive shaft. Installation generally takes about 60 minutes and it requires that the front drive shaft be shortened. It simply bolts to your transfer case before the front drive shaft. "

 

[Loren]

It's a viscous coupling for the front driveshaft of 4WD trucks. See my article in TDR issue 32 (the current one), page 60.

Loren

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2000 Quad Cab, 4x4, short bed, six-speed: U. S. Gear exhaust brake, MileMarker Select Drive viscous coupling, Velvet-Ride spring shackles, Painless Wiring circuit box, Optima yellow-top batteries, Super-Glide 5th wheel hitch, Reese folding ball gooseneck hitch, Drawtite front hitch receiver, Tekonsha Sentinel brake controller, Westin nerf bars, Clarion sound system
1995 Standard Cab, 4x4, long bed, automatic: Firestone Ride-Rite air springs, torque converter lock-up switch, 4" cat-back exhaust, Reese 20K 5th wheel hitch, Reese gooseneck hitch, Hayes Micro Control trailer brake controller, 100 gallon bed-mounted fuel tank with 12 volt electric pump & fill nozzle, Swiss Cap fiberglass cap

 

[SixShooter]

I would but I haven't recieved the next issue yet- I find that odd. Has anyone else not gotten their next issue of TDR?

 

[EricBu12]

I haven't gotten mine yet either.
Hope it gets here soon.

 

[Loren]

Sorry. I have had my latest issue for a while, and I assumed that everyone else would have gotten theirs too.

MileMarker is a company that makes hydraulic winches, locking hubs, and a viscous coupler for driveshafts. The coupler is called a SelectDrive.

A viscous coupler is a unit with two rotating components that are attached to each other by a viscous (thick) fluid. It will allow more or less slippage between the two rotating parts depending upon the viscosity of the fluid used and the design of the coupler. Imagine a torque converter with really thick transmission fluid.

I installed one on the front driveshaft of my 2500 in order to allow me to use 4WD low range while maneuvering a trailer. It also takes the worry out of shifting into 4WD on wet pavement. You don't have to be concerned about breaking anything.

Installation is really simple. See my article when you get your new issue. You have to have the driveshaft shortened by the length of the SelectDrive, so you will have to wait for that work to be done, but you can still drive the truck in 2WD while the driveshaft is in the shop. Alternatively, you can have a new one made and keep the original for situations where you want maximum traction.

Since the coupler is designed to slip, it is not recommended for off-road or other applications where maximum traction is required. It provides enough torque to the front axle that the truck will leave black streaks on dry concrete when turning.

I have, however, had one situation come up where it let me down. I was trying to pull a car from a ditch on a snowy hill. I was backing up the hill to pull the car. The rear tires were spinning (not enough weight on that axle), and the front axle wasn't turning. The coupler would not take that amount of torque, at least in reverse. I don't know how it's designed, but if it's like a torque converter, it provides more torque turning in one direction than in the other. Maybe it doesn't work well in reverse.

All in all, I'm happy with mine.

Loren

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2000 Quad Cab, 4x4, short bed, six-speed: U. S. Gear exhaust brake, MileMarker Select Drive viscous coupling, Velvet-Ride spring shackles, Painless Wiring circuit box, Optima yellow-top batteries, Super-Glide 5th wheel hitch, Reese folding ball gooseneck hitch, Drawtite front hitch receiver, Tekonsha Sentinel brake controller, Westin nerf bars, Clarion sound system ***
1995 Standard Cab, 4x4, long bed, automatic: Firestone Ride-Rite air springs, torque converter lock-up switch, 4" cat-back exhaust, Reese 20K 5th wheel hitch, Reese gooseneck hitch, Hayes Micro Control trailer brake controller, 100 gallon bed-mounted fuel tank with 12 volt electric pump & fill nozzle, Swiss Cap fiberglass cap, ICI chrome nerf bars ***
Towing: 1995 Avion fifth-wheel (33. 5', 14,000 lbs) (belongs to a friend), 1996 Holiday Rambler (32', approximately 6000 lbs), 16' flatbed, 34' gooseneck race car trailer.