Rear differential LS vs. No LS

[STANN]

Well I got the X back from the shop after having the rear axle and rear differential replaced. On my way home, i make a quick exit out of a parking lot on to the street, and what do i feel but the rear inside tire spinning.... before the replacement, i had the stock 3.73 LS diff, and would basically get nothing but some chattering tires (you know, the usual). And when i first drove it away from the lot it felt a bit slower than usual, although i figured it was just because i had been used to our new 5.4L F150. So, what i fear is that the insurance company found the cheapest used diff they could get (cheapest= open 3.27). Is that what this sounds like, or maybe a) my previous diff hadnt been functioning correctly and i had grown accustomed to it b) it feels slower because i had gotten used the the 5.4 (that isnt exactly a speed demon). Thanks for the help guys, although i fear another 2 weeks without my car while waiting for the correct diff.

 

[CBoug76]

I would see if you can read the tag on the Dif Cover, and try and figure out what gears it has that way.....

If it is a differet gear you better NOT use the 4x4!!! you will cause more Damage!

 

[FMExplorer]

Check the tag - and check the speed vs. rpms. Also - call the shop that did the work. If you now have a 3.27, your speedo would be way off unless they changed the speedo gear. Ask the shop if they replaced the speedo gear. Another thing to do is open the cover - if you have standard spider gears, you're hosed. If you have a LS, there will be a flat spring in the center.

J

 

[STANN]

i checked the tag and it has 3.73 and 8.8, but i have a feeling they used the old diff. and axle housing... will talk to them tomorrow, because if this is a limited-slip, it is certainly the strangest LS diff i have ever encountered....

 

[Msupertek]

Ford Certified Technician

I would hope that a shop doing differential repairs on a vehicle would have the sense to not mismatch gears, and to use the correct application carrier assembly. How about calling them and asking them what they put in?? They should know and it should be on your Repair Order.

 

[jimbo74]

also, one tire may slip, as the stock diff with lsd is only suposed to work for 85 foot pounds of torque.... there were times in thaven, that my truck was so side loaded for one reason or another and the lsd didnt make both rears spin, so i was stuck... but when i checked it in 2 wheel drive low range, both rears spun!

 

[STANN]

Yes, i plan on calling them today and getting this straightened out. i'll give you all a heads up when i know something...

 

[STANN]

The place that did the axle swap (Subaru?! grrr, darn insurance companies) says that they put in a 3.73 LS, and through my checking the tag on the differential currently in the truck agrees with that. I'm not too knowledgeable on diffs- Is it possible for a LS diff to work, but not work as a LS diff?- basically have the diff work like an open diff, even though it is "techincally" a LS, or is it an all-or-nothing operation? If this is the case, the issue of a wrong indication on the speedo is unexplained- before the repairs, at WOT, the tranny would shift out of first at 45mph- now it shifts at around 42 or 43. Also, Subaru was saying that 96-00 models all had the same diff, which i thought i knew for a fact to be wrong, as there was a 3.73, 3.53?, and 3.27?- a guy at the collision shop called Ford and ford said that even 4.10s were offered, so hopefully that will clear some of that up. Sorry for the long post, things are moving along painfully slowly and i fear the insurance company will have to get involved again...

 

[Alec]

The insurance company has to make you happy.

I say take it to the shop and have them crack open the diff. Have them check the LS condition, and count the teeth on the ring and pinion to calculate ratio.

 

[SteveVB]

If you have the time- you can do a quick check if you have L?S or not, just jack the rear wheels off the ground and turn one- if they both turn the same direction you have a L/S if they turn opposite directions then its open.

Like was asid above you can overpower the L/S. So yes the LS will act as an open diff after the torque input has been reached.

Good Luck, and ask to be there when they crack open the diff so you can see the teeth count, and if the clutch spring is there indicating a L/S.

Good Luck

 

[STANN]

Perhaps i am overpowering the LS, but i dont see how i could all of a sudden i could be overpowering the LS when i havent been able to do it in 2 years driving previous to the accident...maybe they threw in a 427 just to be nice while they were doing the work

 

[STANN]

After some research had been done, Subaru finally admits they did indeed put in an open diff. Finally! i was beginning to think i was crazy...cant wait to get the 3.73 LS back in....time to eat some rice Thanks for the help guys- this board alone is what made it possible.

 

[CBoug76]

Great! Now Go Get your Limited SLIP!!!

 

[STANN]

ok guys, more issues . I got the LS back in, and all is well and good with the driving, but something is leaking out of the diff. Should ANYTHING be leaking out of the diff? Its definately the diff-fluid, but there is not a lot of it (enough to drip onto the ground and make some decent spots)- it seems to be leaking out of the very bottom of the diff.

 

[Alec]

Mine leaks due to the aftermarket stud girdle. If yours has the stock cover and leaks out the bottom they need to redo it.

 

[STANN]

Goodness Gracious, how many times will they have to redo this darn diff??

 

[STANN]

Well, hopefully it's fixed. The pinion seal was leaking, and the way the fluid was blowing back it made it look like the cover was leaking. Please let it work, please let it work (fingers crossed)