Open rear diff. What a freakin' joke

[Diesel Freak]

Originally posted by Shortshift

What Joe said...



Peg leg diffs are usually safer. They suck for real 4x'ing though.

Open Diffs here... . my right rear goes up in smoke on occation



but for normal steeet driving she works fine..... but we do not have the hills here in portland that you do in Seattle..... some of those are freakin steeeeeeeep. I thought about ordering my truck with a LSD... . but decided against it..... waiting for ARB to produce a Locker for the Dana 80 unless it already exists.

 

[WTBurke]

I'm always on the road because of my job. I run to Montana through Nevada to Idaho and pull the Manida pass at 3AM in a blizzard into Montana. Without a locked rear end I wouldn't even try. The I-5 from Kalifornia into Oregon is also a challenge at certain times not to mention I-80 to Reno from Sacto at 2AM is pretty good too. I don't "wheel" my CTD off road but I do have a little half ton Z-71 Eaton top-spec in the rear and an ARB in the front IT WHEELS very well. The point of all of this for you open "DIFF" guys is..... you really don't know... but I have seen alot of you in the ditch

 

[Utah Willie]

According to my Pocket Reference by Thomas Clover... . a 21% slope is just under 12 degrees. A 100% slope is 45 degrees but it isn't liniear from there as a 60 degree slope is 173. 2 %. It gets real interesting when you get to 90 degrees..... that's infinity! As against 89 degrees, which is 5729 %..... ! So... . when you see the ill-written/researched ads touting the Hummer as being able to negotiate a 60 degree slope... ... ... you will know they meant % but were too ill-informed to tell the difference. 60 degrees is close to the angle of an aerial ladder (FD) for optimum climbing. Can your truck climb that? Can you climb a loose dirt hill that steep? Don't try... the answer is "no".

 

[Diesel Freak]

Originally posted by Utah Willie

So... . when you see the ill-written/researched ads touting the Hummer as being able to negotiate a 60 degree slope... ... ... you will know they meant % but were too ill-informed to tell the difference.

they also neglect to tell you that the angle of repose for dry dirt, sand, gravel etc. etc is 45 degrees

 

[Vaughn MacKenzie]

Mike, I had a '72 GMC shorty once with an open diff, my oh my you didn't dare trepse onto any slippery surface! That truck would get stuck if the ground looked slippery



As far as Open vs LSD operation in snow, it only requires you know what you're driving when it comes to the LSD. Just some practice and common sense and you should be able to steer it back straight when the rearend sidesteps. The ol "steer in the direction of the slide" adage. I've practiced this with my truck so I'm familiar with how it acts, and now it doesn't intimidate me. Fortunately these trucks have a long wheelbase which equates to a high polar moment of inertia (did I get that right Cliff?) which means it doesn't kick out so fast you have no time to react (like the short wheelbase Bronco II I had which was downright scary on slick roads).



Vaughn

 

[WCrovo]

My 99 had LSD and it was a night mare on ice and snow. It always walked towards the curb. When I got my new truck I opted to not get the LSD and decided to install a true locker that I was in control of. I still have an open diff and found no need to change anything. I tow all over in all weather and have had no problems. My experience with factory set up was not great and left me unimpressed. I do feel that a manual locking diff is the way to go.

 

[Bad340fish]

I had a 91 Toyota 4x4 with 33s on it, it had a lockrite in the rear and would do anything you wanted it to in the snow or ice. The rear kicks out pretty easy in 2wd but nothing that could not be cured by letting off the throttle(which releases the locker)



Since it doesn't snow or ice much here I used to always take it out and goof off in the snow. One night when the power went out I drove almost 200 miles screwing around in the snow lol. Now with my 2wd ram with an LSD I am afraid to back out of the driveway. I consider the LSD in my truck to be a "kinda tight" open diff because it SUCKS!!! You can do a burnout and roast both rear tires easy. . but put some water or snow down and the LSD parts seems to runoff

Clark

 

[MikeR]

Sorry all you open diff lovers, I realize we have some steep hills, but this is proof that the limited slip is the better choice. My LSD truck has no traction problems on any of the same hills that this open diff truck has problems with, steep or decent. I'm up in the snow alot in my truck too, wether going over the pass or playing in the snow, and in 2wd the LSD still kicks a** over the open diff.



I had forgotten how some of you don't know what hills are. I had a friend from Texas here a couple months ago and my interior still has fingernail marks from where he dug in his claws when I took him downtown. I thought he was going to soil himself.



Believe me, a limited slip equipped truck is way different (easier) to drive than a limited slip eqiupped car.



-Mike

 

[Scollins]

An automatic locker for a street driven, two wheel drive truck is a real, repeat REAL bad idea. I had a Detroit Locker in my Grand Cherokee that I wheeled, and it was a little scary sometimes (shorter wheelbase. ) Banked off-ramps with ice and snow were the worst. You really have to change the way you drive with a locker (Lockright, Detroit, etc. ) With the ridiculous lift (6"+) and the Detroit locker, my wife wouldn't ever drive it.



An ARB locker would be real nice, as you choose when it is a spool, and when it is an open diff. Just don't forget when its engaged on pavement (axle shafts will go POW!) The draw back is the huge expense ($650 for the locker, and $200 for the compressor) and the fact that the install is not a DIY, so $500 or more for installation. OUCH, $1300!!!!



I suggest that you put in a Detroit TrueTrac, which is a gear driven limited slip (very nice. ) Installing one without a ring&pinion change is really no big deal. I can borrow the tools necessary to make sure the setup before and and after is correct. If we remove the current carrier bearings, the shims are most likely not going to change. With new bearings, the preload is a little different, but shim kits are pretty cheap. With the full-float rear axles, changing the diff doesn't even require removing the wheels!



So, when do we have the BOMB session????

 

[HC]

Originally posted by Diesel Freak

..... waiting for ARB to produce a Locker for the Dana 80 unless it already exists.

It exists! (I've got one)

 

[Diesel Freak]

how much was it?

 

[HC]

Originally posted by MikeR

I honestly cannot see why anyone would want that POS open rear diff... It makes me want to sell it!



If any of you new truck buyers are wondering... don't waste your time with the open diff!

Less tire wear with open diffs is another feature nobody has mentioned yet. Choice is good.

If you got a good deal on the truck, there is absolutely no need to be kicking yourself. Just upgrade your rear end. In addition to the other products mentioned, consider an Auburn gear limited slip. Get it installed by someone with a good reputation for setting up rear ends, and it will probably work better and give you better service than the factory limited slip.

 

[Diesel Freak]

Mike, since it is a light 12 valve 4x2... just put a spool in it, tub the rear, add some 18" Mickies, a different cam plate, some Diamond B's, HX-40 and send Emily to the track.

 

[WCrovo]

MikeR nice opinion but I don't buy it. Had both. An auto locker sucks BIG time. A manual locker is the way to go. Auto lockers are a 1/2 *** way to do it. Given the choice I will take open to auto and manual to everything. If you drove much on snow and ice you would see the humor instantly.

 

[SlyBones]

Imagine manual lockers at both front and rear, that can be electronically engaged and disengaged with a computer. And combined with a Thorsen gear center differential that can shift power from 50/50 to 70/30 in either direction. -- Oh wait Audi is already doing that. IMO the best system out on mass production cars.



I have seen plenty of adds and stuff from the rest. Plenty can shift power from the rear to the front when the rear slip, or have some form of full time AWD, but not with electronic controlled lockers. Usually with some cheap clutch pack model LSD, like we got. There are some real fancy stuff out there on the super cars. But that stuff is out there and expensive.



I think DC should give us the audi system with one enhancement. The ability to switch between 2WD and 4WD. Once in 4WD it behaves like above. But even in 2WD still used the computer to electronically engage the lockers as necessary.

 

[WCrovo]

10-4 Slybones. Audi and VW have it down.

 

[wtrenholm]

DC has Quadra Trac II in the Grand Cherokee. I don't know all that much about it as far a durability or service life of the clutches. But it sure looks like it would work.



They basically run an open diff, and add a hyd pump, a piston and a multi disc clutch. They run the pump/clutch assembly in the front diff, rear diff and the t-case. Using a diff as an example, when one wheel spins faster then the other the spinning side gears in the diff operate the pump which applies the clutch pac and "locks" the diff.



You have the drivability and less wear of an open diff with a self applying locking set up. No compressor, wires or diff noise you get with other products. Could be a POS but who knows? May never be offered in an aftermarket product either.



My dually with it's LSD can feel real loose in the rear on ice/snow even in 4WD. Take a real nose heavy truck, give it lots of torque, add dual wheels throw in a LSD and lets go winter cruising. Good thing I got that short stick sticking up out of the floor next to that tall one. I love my truck and bought it the way I wanted it. But where some aspects improve others decline, so you decide what you want and live with it. Can't have your cake and eat it too.



Happy Holidays,

Wayne

 

[craftybigdog]

about open diffs

The only thing that is terible with open diffs is the tire with the least amount of traction pushes you forward they say a truck with a detroit locker 2wd will go farther than a truck with open diffs with 4wd just my 2 cents

 

[Okie-Go]

I found out that the lsd in my truck was nearly useless. Getting stuck on wet grass with a load of wood ain't fun. I had a loc-rite installed and still like it. I have been stuck with it but it was the weight of the front end that hurt me. Both whhels were spinning and I guess that's what it's allabout.

 

[kswieringa]

Check your figures

A 100% grade is 90 degrees . And a 21% grade is 18. 9 degrees . Trust me I'm a surveyor at times and if not go to aj.com and use a calculator