My door sticker says axle is 19. What gear ratio am I running and is it posi?

I looked all through my manual but came up empty. I also searched here and could not find the answer. It is a '97 F150. Thanks,

Barry

 

"IF" Ford kept the same axle code numbers over the years...then you have a non-posi with 3.55 gears. This is out of my 1989 owners manual...notice the "IF" in the first sentence...Deen

 

[updated:LAST EDITED ON 29-Jun-02 AT 01:30 PM (EST)]How easy would it be to install posi-traction rear-end. Also, would it be wouth it to go up to 3.73? Also I gotta look at what it would cost. I tow a boat fully rigged it is about 3100lbs. I am planning to move up in the future and the new boat should weigh about 6000lbs rigged.

Barry

 

"Posi-traction" is chevyspeak, please don't use that kind of language on this board. The generic term is "limited slip differential" Ford calls it a "Traction-Lok."

The swapout from an open carrier to a Trac-Lok is not particularly difficult IF you have all the correct tools, a shop manual (genuine Ford, not Haynes or Chilton) and the time and patience. You have to pull and reset the existing ring and pinion on the new carrier. The most important thing about setting up a rear end is that there is no such thing as good enough, it's either right or it's crap, no in between.

Aside from normal hand tools, you'll need a dial indicator on a magnetic base, a micrometer, a dial type inch-pound torque wrench and seating tools for all the seals and bearings. You need access to a press to fit the rear pinion beaing and side bearings. Having assistance from someone who knows what he's doing is also helpful.

There's not a lot to gain going from a 3.55 to a 3.73, but if you're changing your carrier, there's actually less work involved in a ratio change than not since you don't have to disassemble the existing R&P.

I changed my 3.08 open to a 3.73 Trac-Lok the winter before last. I'm not sure that I'd do it again myself if I could find a competent shop that didn't want an arm and a leg for the job.

 

Sounds like it is a little more than I'd like to tackle myself, having never worked on a rear end. I may just try to find a local shop that can do it. Thanks for the replies and help.

Barry

 

Like StrangeRanger said, if you have the right tools it is not hard, just time consuming. When you put the thing back together and check play in the ring gear, if it isn't right, you have to take everything apart and start over and add/remove some shim. You may have to take the axle apart 5-10 times before the wear pattern is correct, but it IS something the average backyard mechanic can do. Just take your time, and as said before, there is no "good enough" when it comes to ring and pinion (or diff) swaps. But it is not uncommon for shops to charge upwards of $500 PER axle (just for labor!) for diff and R&P swaps. I was once quoted $1800 for my 97 F250 for a R&P swap with parts, so now I do them myself.

 

[updated:LAST EDITED ON 02-Jul-02 AT 02:15 PM (EST)]OK here goes. I have a 95 ford with a 300 i6 engine. I am also thinking of changing gears but I have a few queations. Do you need to mess with the computer to change the shift patterns of the transmission to match the new gears and is it hard to change the speedo meter to also match the new gears. I have the 3.08 gears and pull a 5000 lb fifth wheel. It pulls it fine until I hit the really big hills. I am thinking of putting in 3.55 gears. What do you all think. I called ford dearlership and they have no clue. they told me to buy a new truck. $30,000 for new truck is to much for me right now. Any help would be apprieciated.


Brian

 

The VSS (vehicle speed sensor) on a 95 senses an exciter ring mounted on the diff carrier. It measures the output speed of the diff (i.e. axle RPM) and does not need to be changed when you swap ring and pinion. It is sensitive to changes in tire diameter though.