RockyMtRunner

I was coming down the two steep descents on the far west end of Rd 379 in Pike National Forest (north of Gold Camp Rd). In past years I have crawled down these descents (rated "Difficult" by Wells) with complete steering control using 1st gear 4Lo, rarely needing to brake. However, the snowy winter and wet spring have left a thick coating of loose gravel this year. As I descended this year for the first time (using 1st 4Lo as usual), much to my surprise I started to slide down and my engine revved up and I sped up as the wheels seemed to let loose and start rolling freely but I was still in gear! I braked and after sliding for a while like my Runner was wearing hiking boots with sliding heels dug in, engine braking kicked back in and all was well. That was the upper hill. This scenerio repeated itself on the lower hill as well, and I started to wonder if I had finally broken something on my reliable little stock Runner. What happened? (Note: I have tested my rig since the above and have successfully crawled down steep descents that afforded good purchase, so I don't think I have a mechanical issue.) I have an explanation of what happened and a remedy that I want to try out unless some of the seasoned off-roaders in this forum tell this newbie he's full of it. I think when my wheels lost slowing traction in the deep gravel, they also lost power, just like what happens in one of those diagonal up/diagonal down situations while climbing and you're stuck. So . . . what would happen if I engaged the Rear Diff Locker for the steep gravel descents? The locker always gets me over those pesky ascent diagonals. Would it also help on a gravel descent? It seems that the rear wheels would continue to turn slowly due to the locker, though sliding somewhat, and the engine braking would continue on the rear wheels. The front wheels would still cut loose from power loss and turn freely, but I would have steering control in front as long as I didn't brake very hard if at all. Is this a possible solution or would it do something real uncool like make my rear end slide around? It would never have occurred to me to use the locker during a descent except last year I hiked along the road and watched "Randy's Extreme Recovery" rig get a rolled Cherokee back on its wheels and then accompany it down from Eagle Rock (370C). Randy's rig is one to salivate over; custom apple-red body with a cool baby-sized crane in the bed, reasonable looking lift with oversize tires, incredible approach and departure angles, pre-'97 straight front axle Chevy large block V8--everything rebuilt, locked fore and aft, and much more than a newbie could notice and remember, but I DID noticed the tell-tale jerky slipping of the inside rear wheel during a turn but not the inside front wheel as the recovery rig crawled down the rocky steep descents. When we got to the bottom, I asked the recovery driver if indeed he was locked in the rear on the descent. "Yup," he answered matter-of-factly, disarming my impression that he might have forgotton to unlock it and I was doing him a service to bring it to his attention. (Remember I'm new at this sport and don't know a heck of lot but would like to be a hero whenever needed. lol.) I didn't have a chance to ask him why he kept the rear locked but not the front while descending. He was in a hurry to give a clipboard with the bill on it to the Cherokee driver and his girlfriend and get on his way. But I did stick around long enough to see the Cherokee guy turn white and gasp as he looked at the bill. I always wondered how much it was. I'm gonna guess $600, only because i THOUGHT I heard the girlfriend whisper that amount in total disbelief. At least the Cherokee was still running and they would go home under their own steam even if the roof was partially caved in and windows cracked. But I never found out why an expert off-road recovery driver with a super capable rig would use his rear locker during a simple descent. Does anyone in this forum lock the rear during a descent? Why or why not? Seems everyone including me celebrate the huge advantage of having the stock Rear Diff Locker for climbing up and over formidable obstacles, but I have yet to hear anyone say he/she uses the locker for descents. (I know I'm overly wordy but I don't post a lot, so thanks if you stuck with me through all this.)

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tc

If it's slick or bumpy, I often use BOTH lockers for exactly the reason you describe. With an open diff, the power (or in this case the engine braking) goes to the wheel with the LEAST traction. Lock the diff and the engine braking is always applied to the wheel with the traction.

Other tips for descending:
- minimize the use of the brakes. Most of your brake power is applied to the front brakes, making an endo more likely if you get scared and jam the brake pedal. Manual transmission vehicles have a serious advantage here.
- be prepared to give it some gas! Throttle is way better than brakes while descending in a lot of situations
- select a low enough gear before you start down. If in doubt, select the lower gear. Much better to take your time than to miss a critical downshift and run down out of control.
- It's not a race!

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RockyMtRunner

Thanks, tc. Info much appreciated.