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Discussion Starter #1
Haven't did a burnout yet and decided to do one the other night. It easily laid "a" black mark as black and long as i wanted to. However there was only one. My window sticker says it haves a 3.73 limited slip, but come on. My dad has 3 f350s and they all do the same thing. I have a f150 fx4 with the same 3.73 ls and that thing will leave two equal black marks. What up with this??
 

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Don't you worry about it
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worn out clutches or to much friction modifier. Mine was doing the same thing at 100k miles. I changed the diff fluid with some valvoline synthetic for limited slips and didn't add any more friction modifier and mine works much better.
 

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Discussion Starter #4
Huh, thanks. I'll try it
 

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my issue as well, i will also swap fluid... i did notice if i start to roast them i get only one then if i let off a sec and then re hit the pedal the other starts burning out also.....i hate always going sideways when im laying down some power....
 

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Traction control off/on?


Sent from my Autoguide iPhone app
 

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How long should I let the rtv dry before I dump some more fluid in? And when I drained the rear end maybe a qt drained out...
 

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I waited about 30 minutes but if you took it to a shop they wouldn't even wait that long
 

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Discussion Starter #10
I waited about an hr and a half. Took it down the road and back and did a boosted launch and it still did a one wheel wonder......... :( guess I have bad clutches inless I need to run it a while for the new fluid to circulate throughout
 

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Mine did the same thing today 91k but if I don't add the limited slip oil will that burn up the clutches sooner? Also how much oil does it hold


2008 F-350 CCLB all stock for now... Deleting and tuning with Vivian's looney street soon.
 

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Discussion Starter #14
Yes the traction control was off too
 

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My 05 did the one tire fire, decide to hammer on it and my 2010 lit up both surprisingly. I have a feeling these trail grapplers aren't gonna last very long :scuffy
 

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mine laid down 2 strips about 50-60 feet long just 2 days ago. it even ripped the yellow parking stripes off of the parking lot. i did flush my rear end like 5000 miles ago though. and im at 90k now.
 

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Mine did the same thing today 91k but if I don't add the limited slip oil will that burn up the clutches sooner? Also how much oil does it hold


2008 F-350 CCLB all stock for now... Deleting and tuning with Vivian's looney street soon.
Yes it could potentially ware on your clutch packs faster. The reason there is a friction modifier in the fluid is to help the clutch packs slip thus reducing wear. Because the clutch packs are allowed to slip your diff acts more like a open differential.

If you don't use the friction modifier the clutch packs will grip much better, but yes you are right it will increase wear. However with 91k miles on your truck already those clutch packs may already be toast. It's hard to say.

I don't know how many quarts are in the rear diff, but you can probably find that in your owners manual.

Kyle
 

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IDK about the traction control

what does it do ?
When the tires start losing traction it cuts power to the motor. There is a button you push to turn it off.
 

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Discussion Starter #20
I have the 10.5 in rear end, not the Dana 80 and it hold 3.5 qt. How much is the re-build for the 3.73 ls? Has anyone here done this? I've just got basic mechanical skills and tools.. or should I wait a few miles to see if the fresh oil helped?
 
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