A while back threads were circulating with regards to replacing the cluth packs in trucks with POSI due to the vibration when taking off from a full stop.

I had this issue and asked the dealer to correct and they didnt (stupid me for not following up but that's another story). Anyhow, the problem went away and now it feels as though I have some gear damage. Im almost due for myt second service and Im going to be diligent about having them correct this.

Anyone else have the POSI vibration turn into gear damage???

 

Hard to believe that Positraction issues would cause gear issues. Since nothing really engages or disengages with the unit. Just the clutches slipping, for turns, or locked straight away.

If I were you. I'd first go to a mall parking lot. Do three figure "8's" tight with the steering wheel hard over each time. Just at a slow speed, not crawling at idle or with your foot in the throttle making the truck slide around. Just at a nice normal speed. Do this in 2wd if truck is 4X4.

If your concerns vanish, which they probably will, it is just the plates chattering and grabbing. Get some additive and have it installed in rear differential. If you have positraction in the front differential do it there too.

You wouldn't believe how many trucks/cars I've repaired doing this.

 

ok first and don't take this the wrong way, but posi is not the correct term. u have a locking or limited slip rear differential.

second its impossible to have gear damage due to the rear diff shudder. and what do u mean it feels like u have gear damage?

Mac.

 

I doubt there has been any damage done to your gears. I had the shudder when turning from a dead stop. My dealer ordered the parts and replaced the clutch pack with no hassles. If your dealer won't do this, find another dealer. They are REQUIRED to do all warranty repairs. It's not up to them to decide what gets fixed and what doesn't. Unless it's blatent abuse that caused the problem.

Their job is to take EXELLENT care of Ford's customers, Ford won't tolerate anything less. That's what the Blue Oval Certification is all about. That's also why the dealers send out those surveys after you have something done. Anything less then 5's across the board threatens their certification.

You may already know all this but it's worth mentioning.

My Gallery *UPDATED*

 

Thanks all for the "schooling"... Ive never really been machanically inclined but I'm going to take a stab at it with this vehicle.

I was referring to a thread where someone mentioned that he took in his vehicle and the service department noticed some of "teeth" broken in the rear axle gearing. When I take off, it feels as though the gears area slipping and once I get going obviously its okay. Almost feels like a worn universal join in the drive shaft...

Also, I am going to try GEARHEAD99's recommendation and see if that takes care of it...

 

For future reference ET, if your ring and pinion gears have teeth stripped or damaged you will know it in no uncertain terms and it won't get better once you get going.

When they are damaged, they are damaged and there is no on/off symptoms.

Rear axles are incredibly durable and my experience has been that you really have to make an effort to damage them - even casual abuse won't do it.

Its good you are learning. So many people just drive vehicles and have no idea what goes on under the sheet metal.

 

ET-I think it was me you are referring to. I had gone to my dealer about the clutch packs. While on the test drive, my service advisor told me the tech heard the beginning of the rear end howl (I never really noticed it). When the rear end was opened up, my SA said the ring and pinion had some unusual wear so they warranty replaced them along with the clutch packs.

I also had the "feeling" you describe. It was addressed on this visit, but I don't know if it was the rear end or PCM. I got the reflash while I was in there for irratic throttle response.

Dealer was great-if you don't get the service you deserve, and are willing to come south a bit, drop me an email. I'll hook you up with my guys.

KE

 

It's great when your on the internet and one guy posts something and you tend to believe it because thats all thats there.

"posi", "positraction", "limited slip differential", "lsd" - its all the same, but some comapnies have better "working" units.

"locking", "e-locker" - locks the rear end so both wheels spin the same speed no matter what.

 

Auburn Gear Positraction
The highly efficient torque transfer capability of the Auburn Gear limited-slip differential is achieved through the use of cone clutches coupled to beveled side gears. As torque is transmitted through the differential side gears to the axle shafts, the side gear separating forces and spring pre-load firmly seat the cones into the differential case. The cone design, along with the applied force, determines the torque transfer capability of the differential. When torque levels decrease, as in a cornering maneuver, the gear separating forces also decrease, allowing the axle shafts to rotate independently. Also, in order to address the non-rebuildable components within the Auburn Gear differentials we are offering the NEW D-REX PROGRAM. If your Auburn Positraction wears out, , you can send your old unit back with a copy of your original receipt within 4 years and for approximately $100(varies by application) you will receive a brand new unit.

Eaton Positraction
Muscle cars, hot rods and mild off-road vehicles should look to Eatons limited-slip differential for their traction answers. And the fact is, Eatons Positraction units are virtually bullet proof. They have precision forged gears for high impact strength and durability, Formula One race-bred carbon friction discs for lifelong, chatter-free operation, and a spring pre-load pack combined with a field proven, high performance cast iron case for unbelievable durability. Eaton Positractions are rebuildable and can be upgraded to 200lb, 400lb, or 800lb springs and plates. You can also upgrade the clutch packs from 14 discs to 18 or 22 steel discs for more aggressiveness.

Detroit Truetrac Positraction
The Detroit Truetrac provides a controlled amount of resistance to a one-wheel spinout, so that the other wheel (with traction) receives sufficient power to keep the vehicle moving. It uses pairs of "Helical" gear sets and no clutch packs to wear out, it is an aggressive unit yet smooth and quiet on the street, the torque bias ratios of 2.5 to 3.5:1 range, and is ideal for lso, in order to address the non-rebuildable components within the Auburn Gear differentials we are offering the NEW D-REX PROGRAM. If your Auburn Positraction wears out, , you can send your old unit back with a copy of your original receipt within 4 years and for approximately $100(varies by application) you will receive a brand new unit.

Eaton Positraction
Muscle cars, hot rods and mild off-road vehicles should look to Eatons limited-slip differential for their traction answers. And the fact is, Eatons Positraction units are virtually bullet proof. They have precision forged gears for high impact strength and durability, Formula One race-bred carbon friction discs for lifelong, chatter-free operation, and a spring pre-load pack combined with a field proven, high performance cast iron case for unbelievable durability. Eaton Positractions are rebuildable and can be upgraded to 200lb, 400lb, or 800lb springs and plates. You can also upgrade the clutch packs from 14 discs to 18 or 22 steel discs for more aggressiveness.

Detroit Truetrac Positraction
The Detroit Truetrac provides a controlled amount of resistance to a one-wheel spinout, so that the other wheel (with traction) receives sufficient power to keep the vehicle moving. It uses pairs of "Helical" gear sets and no clutch packs to wear out, it is an aggressive unit yet smooth and quiet on the street, the torque bias ratios of 2.5 to 3.5:1 range, and is ideal for 4WD front axles or rear axles, as well as 2WD light trucks, SUV’s, cars.

Track-lok Positraction
The Track-lok is a mild and smooth Positraction that can be found in most Ford, Dodge, and Jeep differentials equipped with the factory limited slips. It uses flat and bevel clutches for preload. It is a less expensive unit and recommended for cars and trucks without a lot of horsepower and is simply towing a small trailer or boat.

Power-lok Positraction
The Power-lok is an extremely strong and durable Positraction. It utilizes a 2-Piece carrier case with four pinion gears instead of the traditional two pinion gears. Older Power-lok’s came with steel drive and driven clutches. Later model Power-lok’s come with carbon fiber clutches to avoid noise and chatter when driving on the street. Stock Power-lok’s usually come with the clutches set-up smooth, but by restacking the clutches in different orders and with more bevel discs, you can make it more aggressive. This Positraction works great in many applications except for rock crawling

 

Looks like my post got doubled and scrambled up somehow. I’m not going to try to edit it because it will probably screw it up worse

Why can't you edit a post and fix it? RP