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changing rear diff oil

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Old Aug 18, 2012 | 04:49 AM
  #16  
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From: Buckenderra
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ok i replaced my diff oil with a 100% synthetic oil with the additive already in it. i got this stuff cause the first oil i got with the 2 additive bottles was not synthetic and on removal of the diff cover a tag attached to one of the bolts said 100% syn only.
i was hoping it would tighten the LSD up but it still slips when turning on takeoff, the inside wheel will spin especially in the wet and makes it had to get across busy traffic. when the car is straight and i plant the foot the LSD works fine. does anyone have some ideas on what i can do to tighten it up a bit. i dont mind if it hops a little round corners..

cheers guys
josh
 
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Old Jan 22, 2023 | 10:10 AM
  #17  
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Venturi Pump

Make yourself a homemade venturi pump. I've used one for about 20 years.

This is the one I've used for awhile now.

Black hose goes into the differential thru the fill plug and you insert your air into a hole drilled into the other line. Pointing the air to blue or the open end of the house. A suction is created in the jug that will pull the oil right out. Hope this helps. SINCERELY YOUR LOCAL HILLBILLY EINSTEIN
 
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Old Jan 22, 2023 | 11:19 AM
  #18  
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Even easier is just buy the 1 quart squeeze bags that Amsoil and probably some others offer. Genius idea. Last time I filled a rear diff with product that came in hard plastic bottles is was a real PITA because of how my particular truck is. Same thing with a manual transmission. I would now use the squeeze bags into the fill plug and would not bother taking apart the shifter and pouring in through the top as I have before.
 
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Old Jan 22, 2023 | 02:11 PM
  #19  
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There is an rtv made for gear oil exposure, don’t remember the brand i used. Worthwhile to pull the cover and flush/wipe and inspect the bottom of the housing…
 
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Old Jan 22, 2023 | 02:52 PM
  #20  
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From: Kinnula,Finland

I'm boring and using this type.
 
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Old Jan 23, 2023 | 09:28 PM
  #21  
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Lube locker gaskets are awesome.
 
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Old Jan 25, 2023 | 08:31 AM
  #22  
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I just use my pneumatic Harbor Freight brake fluid bleeder and suck it out through the fill port.
 
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Old Jan 27, 2023 | 08:35 AM
  #23  
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From: Bahstun
IMO

what a bunch of lazy DIY mechanics

remove the cover, wipe out the bottom and you will be amazed on what crap can be left in there

BONUS, you get to inspect the internals and can even take a pic to compare wear for the next time
 
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Old Jan 27, 2023 | 01:23 PM
  #24  
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Easy now. Don't be so hard on us DIY'rs.

My cover is stuck on.and will not pry off without damaging it. (See avatar for pic of cover).

I'm thankful for the drain plug. I have no idea what the wear on the ring gear is.

I use synthetic for the fill, and hope for the best.



Originally Posted by knottyrope
IMO

what a bunch of lazy DIY mechanics

remove the cover, wipe out the bottom and you will be amazed on what crap can be left in there

BONUS, you get to inspect the internals and can even take a pic to compare wear for the next time
 
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Old Jan 27, 2023 | 02:56 PM
  #25  
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i said IMO but you do present a unique rare end case
 
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Old Jan 29, 2023 | 06:46 AM
  #26  
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When I change the rear differential oil I use Mobil 1 gear oil ( I use the gear oil viscosity as per the Ford manual.)

I called the Mobil hotline and they said the friction modifier is included in their gear oil.

In the end it needed 1 extra small bottle of Ford friction modifier added as well to make the limited slip work as designed.

I have done this a few times over the years and no issues at 395k on the rear diff
 
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