'99 f350 DRW lsd rear. The other day, I was driving about my rear end seem to lock up in a turn. If I was making a left the left side if right then right. I guess almost like a locker rear( never ridden in one so I dont know). Either way it scarred the crap out of and heart sank into stomach. Talking to some guys they say change fluid and hope no metal parts are in the pumpkin. If the fluid soesnt fix it then change the clutch disc's. Do these limited slip rear ends have clutches? If so, how do I check them so I dont waste $100+ worth of oil. Thanks for your help.

 

wanameyer. Yes they do have clutches and if you have a lot of miles, 100K, or so change the fluid and add the additive. Another fix is to go to a parking lot and drive slowly one direction in a tight circle and then the other. That will take the "grab" out

 

Calli, How do I know if the clutches are on there way out. I have 216K miles

 

Jack up the rear end and spin a tire. If they spin in the same direction you still have LS capability. If they spin opposite directions, then you have no more LS.

This test is a PASS/NO PASS test. It wont tell you how good the LS is because there is no traction or resistance to either tire. You could also do a burn out. 1 stripe no LS, 2 stripes good LS.

 

I had a similar issue and it turned out to be a broken spider gear...I don't think worn LS clutches would cause a lock up when turning,you just wouldn't have LS..

 

Let me add my limited experience. I had the same thing happen to my limited slip rear differential in 2007 after the 4x4 converter rebuilt the rear differential while changing the gearing from 3.55 to 3.73.

The 4x4 converter told me to just add one more container of the Ford LS friction reducing additive (for a total of two). I did and it solved the issue. I also may have reduced the effectivenes of my LS.

When I changed the diff. fluid last year I removed the diff. cover and inspected everything and then filled with new Mobil 1 synthetic diff oil but only one container of Ford friction reducing additive and the problem did not return. So, I just returned the second container of additive I had purchased to use only if I needed it.

You may want to buy some synthetic diff oil and two containers of the Ford addititive and then remove the diff cover and inspect for broken spider gears etc, and if everything looks o.k, put your diff cover back on, fill with new fluid and one container of additive. And if the problem persists, suck some fluid out to accomodate the second container of additive, and add the second container and see if it fixes it.

I once had an Int'l Scout with a newly rebuilt diff which would fishtail swinging about a foot side to side driving 25 mph on ice and snow bec the diff was locking and unlocking as one or the other tire lose traction on a patch of ice.

When I get around to it, I plan to ditch the whole LS thing and go with selectable lockers front and rear (ARB or somebody else).

 

Ok great at least now I have a better starting point. Will let y'all know. Thank you

 

i might have missed something here but if it is 4 wheel drive make sure it is the rear doing it ond not the front if an axel universal joint is starting to sieze when you turn they freeze and cause a binding that is about the same, just a thought

 

My fault I forgot to mention its 2wd

 

Well, removed the cover and bad news. Some of the teeth are chipped at the very edge. time to find a new rear end. Does anyone know what could have caused this. I dont feel comfortable rebuilding it but just out of curiosity how could I prevent it in the future? Thanks guys.

 

Well that's beyond my limited experience. (Although, I once held wrenches for someone while he rebuilt a differential for me ... he had the experience and did the work.)

Are the chips on the pinion gear, on the ring gear, on the spider gears, etc.?

The more knowledgeable guys on this forum want pictures. You can upload some pictures to the Pictures & Album folder in your CP on this forum and then right click to copy them from your album and then paste them into this thread to post them into this thread. Then maybe you can draw some more knowledgeable guys out of the woodwork to help.

 

Post up a photo of you can . And is it chipped on the ring gear or on the spider gears? Because before you going looking for a complete rear diff I am sure it something that can be fixed or rebuilt.

 

OK well I finally just broke down and took my truck to my uncles mechanics shop and this is what he found

 

schlepprock250 called it!

 

OUCH!!!! That hurts !! So I take it your uncle is fixing it for you? Or did he find other damage too?