REPLACING REAR END - MATCHING GEAR RATIO

  • Tiny
  • Don F
  • 2005 FORD F-150
  • 4.6L
  • V8
  • 4WD
  • AUTOMATIC
  • 110,000 MILES

Need to replace the rear end in my F150. I nned to know info on matching up the gear ratio with the front transfer case so all wheels will turn equally in 4WD. Info I have - Axle ratio, 3.55. Axle code, 19. Does this mean that I have to find a rear end with 3.55 gear ratio? I am not a mechanic, but would like to find a used rear end to go in.

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Wednesday, July 16th, 2014 AT 11:55 AM

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  • Tiny
  • Hmac300
  • EXPERT
  • 45,641 POSTS

Yes you need the same gear ratio otherwise you'll need the pcm reprogrammed.

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Wednesday, July 16th, 2014 AT 12:13 PM
  • Tiny
  • Don F
  • MEMBER

Ok, I talked to my guy, he says those numbers are correct for the rear end gear ratio. As long as what he has matches, I'm good. If not I will not take it. Thank you!

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Wednesday, July 16th, 2014 AT 1:44 PM
  • Tiny
  • Hmac300
  • EXPERT
  • 45,641 POSTS

A lot of the gears are marked like 35-10 on the ring gear which would be a 3:50 ratio so if you pull the cover off you could see it but the guy probably know what he is talking about.

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Wednesday, July 16th, 2014 AT 2:57 PM

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