Brendan

i did it once... by accident. it made a bad sound.

89silverpu

I don't know the grade all I know is that its really steep. If anyone on here knows Vacaville and they 4 wheel they know Bob's property (this place is very well known for extreme ravine kinda crawling and only heavily modified vehicles make it through the trails...theres a lot of posting up on Pirate about it) its on the same road, Mix Canyon, getting up into the hills that property is located except it gets alot steeper up at the top of the road, the military has radio antennas up there and all the major news broadcasters in the Bay area have their doplar radar on top of these hills. I guess technically they are mountains but just really small ones...and my truck also came stock with 28's so I don't have the "right" gearing for 31's that some yota pickups came stock with so that probably has something to do with it...

89silverpu

I actually just checked online and the road, Mix Canyon road is 23% at its steepest...

4Crawler

iTrader: (3)

I use 2L to go up the very top of Hwy. 4 in the California Sierra Nevada to Ebbetts Pass. I forget the exact gradient, but I think it is over 20% and with the ~9000' elevation and a load of camping gear in my '85, the little 22RE needs all the help it can get. It'll climb fine in 1st gear 2H, but 2nd is a no go. In 2L, I can use gears 1-4:
- http://www.4crawler.com/4x4/4R_TechI...l#Transmission
Handy for both climbing and descending that steep winding section of road at the top of the pass.

89silverpu

Thats exactly what I'm getting at, I could use 1st gear 2H all the way but it would be bogging down at the top and I would be going nowhere so I use 4lo to be able to get into 3rd gear and go 15-20 mph instead of like < 10 mph in 1st gear 2H

thook

Something I've noticed....

The drive into my property is rocks, gravel, dirt, ruts, etc. Rough and steep going in and out. I used to shift into 4wd lo with the hubs unlocked to climb in and out all the time (if it wasn't wet, muddy, or snowed) until it occurred to me it might be hard on the rear diff descending. What I noticed is that when the rear of the vehicle hops a bit going over rocks, the front...being unlocked and freewheeling...will gain momentum and the rear diff gears are stressed when the rear tires make contact again. The rear of the drivetrain is not traveling/geared at the same rate so there is an impact and jerking when the rear meets the road. This is even with light application of the brakes.

Maybe it's not a problem. It certainly isn't on smoother/paved surfaces, but it really does seem to be hard on it otherwise. Now, I just lock the hubs when I go in and out and unlock them when I reach the main road. It's certainly easier than servicing the vehicle because I'm being lazy.

4Crawler

iTrader: (3)

Yes, for descending, the front wheels do a better job of controlling speed since they have more weight on them, opposite of climbing a steep hill. Also, the front diff, since it is running in the reverse direction, will have the gears loaded on the stronger drive side (assuming a regular low pinion diff).

thook

I'm not following. Are you agreeing that it is harder on the rear diff gears under the circumstances I illustrated?

4Crawler

iTrader: (3)

Yes, the rear end is lighter going down hill and therefore more likely to hop as the tires catch and lose traction. Also, with the rear gears on the weaker coast side of the teeth, they are more heavily loaded.

Not likely to really damage anything I suspect, since you are going slow and there is not a lot of traction to impart a lot of torque to the gears. Just pointing out in my earlier post that having the front tires helping out going down hill is a good idea. Also, having 4 tires supplying braking force is better than 2, since it is unlikely that you'll get all 4 tires hopping in the air at the same time.

thook

No...I never get all fours hopping at the same time. And I agree...having all fours for braking is better than two. I would imagine, though, even if it will not "damage" anything...like breaking something....it would still wear faster/harder on the driveline and pinion/trans case output bearing. Shoot...maybe even axle bearings. And those folks with a chain driven case, the chain.

Speculating...I suppose.

just a 22re

well i use 2lo for parking back in milwaukee