3.0, 3.73 speedo cable drive gear ?
#1
3.0, 3.73 speedo cable drive gear ?
was wondering if anyone had the same truck and knows what color my gear is. i have driven next to someone and figured out about my speed difference more or less (would like some advice on that to) but i have not taken it out and looked. Is this hard? i had 225 and now 32's with 3.73s soo just trying to get my speedo right, its about 8-10 mph off going 60 on my speedometer really im going about 69 sooo, need to change it or imma get a ticket. thanks for the advice and help!
#3
#4
97 and earlier use the gears. 98~2000 are driven from the rear axle ABS sensor. 2001+ are driven from a transmission sensor.
If your 2000 truck has 4WABS, the correction is done in the 4WABS Module.
If it has Rear ABS only, the correction is done in the Generic Electronic Module (GEM),
A dealer can change it easily but you may have to supply the tire "revs/mile" from your tire manufacturer's website. As an example, my 31" BFG A/Ts are 677 revs/mile. Your 32" tires should have a slightly lower number.
I don't know how much they charge for that service. Any Ford dealer will have the special tool. A well equipped independent shop might also have it.
If your 2000 truck has 4WABS, the correction is done in the 4WABS Module.
If it has Rear ABS only, the correction is done in the Generic Electronic Module (GEM),
A dealer can change it easily but you may have to supply the tire "revs/mile" from your tire manufacturer's website. As an example, my 31" BFG A/Ts are 677 revs/mile. Your 32" tires should have a slightly lower number.
I don't know how much they charge for that service. Any Ford dealer will have the special tool. A well equipped independent shop might also have it.
#7
Try this site. It will tell you the diff between the tire sizes.
Just plug in the old and the new size. If you can't find your
new tire size, just try to find one close to 32"
ex. 305/70 X 15 = 31.8" & 315/70 X 15 = 32.4"
That should get you in the ball park.
http://www.miata.net/garage/tirecalc.html
Just plug in the old and the new size. If you can't find your
new tire size, just try to find one close to 32"
ex. 305/70 X 15 = 31.8" & 315/70 X 15 = 32.4"
That should get you in the ball park.
http://www.miata.net/garage/tirecalc.html
#8
Be careful with "inch-size" tires. Contrary to logic, most run smaller than the number embossed on the sidewall. "32s" may actually be 31.4" or 31.7" or some other rolling diameter. There is even some variability among tire models from the same tire company. For greatest accuracy, it is best to look up the true revs/mile figure for your specific tire size and model on its manufacturer's website.
#10
yes i plan on regearing, wanted to put a 4.10, L/S 8.8 rear end in before i got these tires, but my tires are balddddddddddddddddddd, and unsafe even with some water from sprinklers on the road i get loose. is it tru that 4.10 gears will put me back withing a mph or so on my speedo with 32s? thanks
#11
#12
No. For 98~2000 ONLY, the vehicle speed is measured at the ring gear which runs at the same revs/mile as the tires. For these three model years, a change in tire diameter changes the speedometer reading but axle ratio doesn't.
Last edited by V8 Level II; 11-07-2008 at 01:48 PM.
#13
2001+ Ranger PCM's have VID BLOCK that sets calibratable upper and lower limits for revs/mile. The VID BLOCK limits only allow for a range of revs/mile that match the stock combination of axle ratios and tire sizes that were originally available with the factory calibration.
An aftermarket PCM flash programmer can reset the speedometer calibration in a 2001+ because the speedo parameters are in kept the PCM.
A programmer wouldn't work on a 2000 though because it has the adjustment in a different module that the programmer cannot reach.
I believe that the OP's 2000 may have a wider range of adjustment available for revs/mile because the flash adjustment for the speedo cal is done in the other module which probably doesn't have anything like VID BLOCK.
#14
Unregistered User
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once again i have been corrected by the master !
yeah i always get confused with the 2000-2001 stuff bob.
anyway the best ford could give me was 677 rpm. made it close with my 32's and stock 4.10's
after re-gearing to 4.56's now my speedometer is 7-10 mph FAST!!!
i am not sure if ford could change the gear ratio in my pcm via re-flash to 4.56
yeah i always get confused with the 2000-2001 stuff bob.
anyway the best ford could give me was 677 rpm. made it close with my 32's and stock 4.10's
after re-gearing to 4.56's now my speedometer is 7-10 mph FAST!!!
i am not sure if ford could change the gear ratio in my pcm via re-flash to 4.56
#15
I believe that 4.56 is not allowed by VID Block since it is outside of the stock range of 3.55 to 4.10.
On the other hand, you might be able to fool it by using the revs/mile that correspond to a smaller tire size along with the 4.10 RAR.
225/70-15 tires were OE on base Ranger models for many years. Their 761 revs/mile along with 4.10 RAR should make your speedometer a lot closer to the 32's with 4.56.
677/761= .890
4.10/4.56 = .899
That would only be about a 1/2 MPH difference at 50 MPH.
Of course, that assumes that VID BLOCK in your PCM will allow that combination of revs/mile and RAR ... it might not depending on the equipment combinations that are covered by your truck's calibration.
On the other hand, you might be able to fool it by using the revs/mile that correspond to a smaller tire size along with the 4.10 RAR.
225/70-15 tires were OE on base Ranger models for many years. Their 761 revs/mile along with 4.10 RAR should make your speedometer a lot closer to the 32's with 4.56.
677/761= .890
4.10/4.56 = .899
That would only be about a 1/2 MPH difference at 50 MPH.
Of course, that assumes that VID BLOCK in your PCM will allow that combination of revs/mile and RAR ... it might not depending on the equipment combinations that are covered by your truck's calibration.
#17
You could see if the cal will allow 721 revs/mile with 4.10 RAR. 721 corresponds to a 235/75-15, also a Ranger size for many years. Without a true spec, I would assume something like 635 revs/mile for the 33s.
635/721= .881
4.10/4.56 = .899
Gives about a 1 MPH difference at 50 MPH. Still not bad at all.
635/721= .881
4.10/4.56 = .899
Gives about a 1 MPH difference at 50 MPH. Still not bad at all.
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