Hey guys,

So after this big snow storm in WV and being stuck 3 times and having to be pulled out by a bull dozer 3 times I have decided that I need to upgrade my differential. What I REALLY want is lockers such as the power wagon has. What do you guys think the best thing for the money would be? I am on a budget. A new LSD perhaps. I think I just want to do the back first. Would rather have something automatic that would just lock in when the wheel spins just because it seems it would be cheaper. Can I keep my stock gears?

Thanks in advance.

 

 

get a air locker that way you know you have both wheels locked when you want them lsd diffs for me have always let me down like you stuck

 

Selectable locker (Air locker) or posistraction for the rear unless you want funky handling. Ratcheting lockers like Lock right, EZ locker, Detroit, and Yukon gear lockers are ratchet lockers and there is a certain amount of slop required to change the direction of the ratcheting operation-so it works forwards and backwards. This slop also allows some buildup of force sort of like an air impact which is hard on u-joints, and the locker will steer you out of corners if you aren't smooth with the throttle.

In the front, if you don't have a CAD (center axle disconnect) that unlocks one axle- I don't think you do, there are only two reasons to not get a locker in the front. One is they are hard on axleshafts, and you might break one. And the second is that the front locker will fight your steering when engaged in 4x4.

The idea that putting a ratchet locker up front is hard on the 2wd handling is almost exclusively urban legend. The place where the ratchet lockers handle funky is in the rear, so that's where you want a selectable (they act EXACTLY like an open diff when unlocked) locker or a positraction in the rear.

To give you an idea of what the force of a ratchet locker is in the front with the 4x4 disengaged, I just inspected a 40,000 pound rated rear axle on a recently acquired type 3 fire engine that has a Detroit locker. I jacked it up and spun one tire *with my hands* to verify it had a locker. When there is no power to them, they ratchet pretty freely. Put power to them and they slop around, bind up, clunk and pop. But they will pull you out of things you couldn't immagine you could get out of.

The reason you don't want a posi or ratchet locker up front with a CAD is that the locker will ratchet constantly in 2wd, and a posi will burn up spinning one side all the time. Unless you disable the CAD so it keeps both axles engaged, that is.

PS I have heard that the 3rd gen's can stuff 37" rubber on stock backspaced wheels, that might help a little. Also, google "picket system"- gives you a solid anchor point as good as a tree to winch out of. I use them for rope rescue, and they are more stable to tie off to than a 4x4 pickup truck.

 

You sure you don't already have a lsd? Diffs aren't cheap no matter which way you slice it. Are you going to do this yourself? Lots of little things go into doing it right and also keep in mind it's about 70lbs with the ring gear attached.

 

Some of these tracks have limited slip diffs, and some don't. It was an extra cost option. Oddly enough, some people and dealers ordered 4x4 trucks without LSD.

The LSD that dodge uses is a modified gleason worm gear. It's very smooth, and does not use clutch packs. No need for friction modifier, and they last just about forever.

The down side to a worm gear is that if one tire has zero traction (in the air or on ice), all the power goes to that side. A slight application of the brake pedal will overcome that.

I have heard you can use a worm gear on the front differential, but I don't know if that's true. I don't know anybody who has actually tried it.

The one item that has the greatest impact on traction is the tires. Not the diff, or axle, or anything else. It's the tires. Ask any rally racer, and they'll tell you the same thing. I run stock sized Michelin's, on a stock truck. I never get stuck. And I've driven through some tremendous snow storms, with snow and ice up over the bumpers.

If you're getting stuck, there's something else that needs to be fixed.

 

Thanks for all the replys.

I am sure that I do not already have an LSD in the rear because I am getting stuck way to much. I got stuck again yesterday and had to have my Dad and his Jeep Wrangler pull me out. I would have one front and one back wheel pulling and that was it. It seemed like it was always the wrong two wheels spinning too. After reading these replys I think I would rather have an air locker that way I can control it.

 

I agree but what could it be? I have kelly safari tsr 35 inch tires. Seems like they should be doing better than this.

 

That's a good tire, and should get excellent traction. Over inflation will decrease traction. Are they wearing more in the middle than the outside?

What happens if you apply a little bit of brake pressure?

 

They seem to be wearing pretty well. Could be better but it is even at least.

Have not noticed on the brake pressure thing

 

A worm gear will send all the power to the side that has zero traction. If both tires have a little bit of traction, the power goes to the side with the most traction. Adding a little bit of brake will be the same as adding a little traction, and then the diff sends power to the one tire that's getting the most traction.

 

That is a good description of the performance of a clutch pack type positraction. Application of the brakes puts a preload on the spider gears which transfers gear deflection to side gears which in turn push against the clutch packs to make the posi tighten up.

Helical gear posis basically act open until one side starts to spin, and gear friction progressively transfers more and more torque to the spinning side the faster it spins out. They will still pull one-leggers, but torque will still be transferred.

Clutch pack posis rely on traction on both axles to develop the gear deflection to engage the clutch packs, so if you have NO traction on one side they are close to useless as the preload springs on posis generally can't put much force on the packs. All the preload springs do is give the posi a nudge to stay engaged. The bulk of the lockup torque is from the gear deflection of spiders to side gears. This is why the engagement of the brake helps. It creates resistance for the gears to push against so the deflection forces can engage the clutch packs.

Helical gear posi is completely loose until you get some wheel spin then it tightens up progressively with the wheel spinout as the friction increases due to spin differentiation.

Clutch pack posis start out LOCKED but very loosely locked (preload springs pushing on clutch packs) and lock up tighter as force (spider/side gear torque deflection) is applied as long as there is resistance. As soon as a tire has virtually no resistance, there is no gear deflection, and ONE LEGGER.

There are also other variations of helical posi that further amend the bias. Most common being steeper cut on the worm gears, but also friction pads on the ends of the worm gears to add resistance, and the new "wavetrac" helical posi that the worm gears have radial wrinkles one one side of the worm and a spring on the other which creates a pulsation in spinout forces that makes for a pulsating lockup preventing ANY sustained wheel spinout.

I was unaware of a rear torsen (helical) available for the AAM 11.5". They are available for the 9.25" 33 spline front though. Source? EDIT: I found them. Came in the smaller 10.5" axle used mostly on the gas engine trucks. I was looking only at the stuff for the 11.5" axle. :P

I'm planning on putting a Yukon rear (ratchet locker) and helical front in my wife's truck, along with 38 spline 4340 axles, but you can also E-lock (selectable locker) the front if you want to do some grinding and drilling on the housing to have a pushbutton front.

 

Oh, just realized there's an important question not answered:

Yes you can use your stock gears. Some axles have a "carrier split" for different ratios, but the only split I am aware of on these axles is between manufacturers. IE if you use a Chevy AAM ring and pinion on a Chrysler AAM axle you need a spacer.

But you will need to consider that once you get the traction device it will need carrier bearings, and you will need to measure "backlash" of the ring and pinion gears before disassembly and reset it to close to the same (very close hopefully) when you reinstall the carrier. A special puller is needed to get the carrier bearings off, but your local machine shop may do this for you for a small fee. Or just buy new ones and press them on.

I haven't yet worked on these particular axles, but most axles use shims to adjust both the gear backlash and the carrier bearing tension. A dial indicator is needed to measure backlash, and you will want at least a "minor install" kit for the carrier shims.

Some axles (like Toyota 8" and GM 14 bolt) use screw type carrier adjustments so you can reset backlash and bearing preload just with a spanner wrench or *carefully* with a hammer and punch.

Full floater rears are STOOPID easy to get the carrier out of- you don't even need to jack up the truck. Pull the axleshafts partway out, drain diff and pull cover, blast off carrier caps and pry the carrier out. Case spreader is sometimes required to get it back in though. The front you have to get the axles out to get the carrier out, so plan on pulling brakes, bearings, and possibly knuckles before even worrying about the carrier.

 

Correction:

Found helical for 11.5" and case spreader not required. In fact other than addressing the carrier bearings this has got to be THE easiest axle to put a traction device in. Re-useable diff cover gasket and threaded bearing adjusters. Be prepared for lesser 1/2 drive impacts being unable to get bolts off though. Particularly carrier bearing cap bolt and *especially* ring gear bolts.

Here's a couple sources for lockers/posis links go to rear 11.5" axle, but the 10.5" rear and 9.25" front can be selected.
http://accuautoparts.com/list1.jsp
http://www.ringpinion.com/DiffWizard.aspx

Carrier split is at 3.73:1

 

I have a detroit trutrac (worm gear LSD) in the front of my diesel and I love the thing. Wouldn't know its there driving around town but the added traction is very noticable. I have the stock LSD in the rear. I was looking to put a detroit locker in the rear, but I haven't gotten stuck again since doing the front a year ago. I figure I'll wait until I get stuck again before I spend the cash.