11/19/11
I have been using this truck as my daily driver twice a week.
The shop that initially installed the locker had used conventional 75w90 oil. After I reinstalled my locker in late September (I had removed it for a couple months), I put in Mobil 1 75w140. The locker is SIGNIFICANTLY smoother and quieter than it was before (and it wasn't even all that bad before). I drive my truck normally now, and that includes cornering at normal speeds. Most of the time, I don't even realize the locker is there. U-turns with the steering wheel cranked are still a little iffy, and I occasionally get a soft clunk in parking lots. Other than that, the locker is smooth and quiet 99 percent of the time.
I haven't had the chance to test out the locker in deep powder or ice yet. I'll add one final review of the locker here after I've had the chance to drive my truck in a couple of storms. At that point, I'll know whether I'm really going to be content to run this locker for a long time - or whether I'll move the ARB locker up on my wish list.
1/16/12
This has been the driest winter we've had in the 10 years that I've lived here - but we FINALLY got enough snow to test out the Spartan. I didn't die like some of my friends told me I would. We got close to 2 inches at my house and in the other outlying areas of town. I took the truck out for a while and drove it in a variety of conditions: 1) quiet back roads with an inch or two of fresh snow, 2) city streets with stop lights where the snow had been compressed into half an inch of ice, 3) twisty roads through the foothills, 4) the freeway in 2WD, which had very little snow in the travel lanes but mounds of snow in between lanes.
I found the Spartan to be very smooth and predictable in all of these conditions. Most of the time, there was no noticeable difference between driving with a Spartan and an open diff. There were a couple intersections where the vehicle in front of me lost traction and got some tire spin. My locked rear diff would keep the truck traveling in a straight line, with no wheel spin, through these same spots. I made a couple of 90 degree turns on the ice that caused the axle to stay locked - but the locker was very smooth and predictable. The diff would stay locked and I could feel one tire slipping through the curve. The axle stayed locked throughout the entire curve (never unlocking and locking at random). Because everything felt so predictable and controlled, it was very easy to drive through these curves.
I played in 2WD a little bit, on ice and in 2 inches of powder, on flat ground and hills. I intentionally got the truck to fishtail to see what would happen and practice pulling the truck out of a skid. If the truck started to fishtail while I was giving it gas, the Spartan would lock up. If I then depressed the clutch pedal and steered into the skid, it would unlock immediately. Coming down a hill, I would also lightly apply the brakes when I depressed the clutch. (Having ABS makes me feel a little more comfortable applying the brakes on ice.) I was going pretty slow while doing all of this, but I never felt like I was in danger of losing control of the truck and I had no difficulty regaining control either. I've had plenty of practice driving a vehicle in snow and plenty of practice driving with a locker now, so combining the two was easy.
I try to drive sensibly in the snow. I don't drive 10 mph with white knuckles, but I also don't drive too fast or tailgate. I was going about 35 mph on most of the surface streets and 55 mph on the freeway. I tried my best to drive "normally" today to give the Spartan a fair test - but admittedly I was probably cornering a little bit slower than I typically would, and I was little bit quicker to put the truck into 4WD and slower to take it back out.
Does my locked 4WD truck perform better in the snow than my FWD car? Tons. Do I still feel safer driving the truck than my car on an ice-covered road? Absolutely.
1/23/12
I went wheeling in the mud all day Saturday and most of Sunday. I have mixed feeling about the Spartan in the mud. It seemed to help maybe 75% percent of the time and hinder the rest of the time. It made it easier to go from a dead stop and KEEP the truck in a straight line if it was already going straight. But if the truck fishtailed (or slid sideways down a hill - eek), there were times that the locker seemed to make the truck a bit more squirrely.
After leaving the park each day, I noticed that pavement + mud covered all terrains made the Spartan chirp on the first couple of turns until the mud had fallen out of the tread.
I drove over Donner Pass last night during a small snowstorm and to work this morning in some slushy snow. I still don't notice any difference in handling from when I had an open rear diff. I even got braver this time and had the truck in 2WD a little bit more. No issues.
2/28/12
I drove the truck last night on some nasty ice for about 10 miles. There were snow showers all day long, but the snow melted as it hit the pavement from the heat of cars driving on it. Late last night, after the sun went down and the traffic was gone, that melted snow had turned into a solid sheet of glassy ice. It's the type of ice that I fear the most - it doesn't matter whether you have a 4WD or 2WD, or what type of tires you have, there simply isn't any traction. It's almost impossible to walk on too.
The truck was in 2WD because there wasn't any snow on the roads. I didn't feel that 4WD was justified or that it would even help much.
My truck started to fishtail a little bit on two occasions while coming around a curve. I've had the same thing happen in 2WD on ice when I still had an open rear diff, so I believe the truck would have fishtailed even without the Spartan. Each time it happened, I just took my foot off the gas pedal and was able to regain control immediately.
Am I finally willing to admit that an auto locker might be dangerous in some conditions? Nope, not yet.
After having this locker for almost 9 months, this is the best piece of advice I have to offer: Keep your foot on the gas pedal going through a curve. Contrary to popular belief, the locker behaves better on a curve if you are accelerating rather than decelerating. If you will be slowing down while turning, depress the clutch pedal BEFORE you start to turn. (If you let up on the gas in the middle of a curve WHILE IN GEAR, the truck will buck.) Then, release the clutch pedal as you start to accelerate through the curve. You can even time your shifts around this so that you aren't putting extra wear on the clutch. It sounds complicated, but I promise it's not. After some practice, the process is quick and smooth, and it has become second nature to me. I catch myself driving my other car the same way simply out of habit.
This should be my final update. I've used the locker in damn near every condition now.