Gears help..

[the5.ohh]

(Posted this in LateModels section)--Looking to buy 3.73 Gears. I have an automatic 1995 Mustang GT with the stock 2.73 gears. Want to upgrade to 3.73s but was told the speedo will be off by 5-7% or something like that.. What else will I need to make the speedo accurate? Speedo gear / drive gear? I'll be getting the following
Ford Racing 3.73 Gears
Ford Racing Friction Modifier
What gear oil do I need? All i see is for manual trannys on your site. Need help to clear up my confusion lol, thanks

 

[joekd]

Ford Racing speed dial will get your speedo perfect, I used royal purple gear oil 75w90 in my rear end when I did the 4.10s

 

[whiplash473]

AM has output shaft gears to make your speedo read correctly..like $12 and AM has free shipping......and what joekd said - royal purple 75_90..has the friction modifier in it


Sent from bored/stroked iPhone

 

[the5.ohh]

Outshaft gear is the Drive or Speedo gear? AM and LMR said theres no correct one for an auto w/ 3.73s i forgot which it was think it was the driveshaft gear. 75w90 gear oil is for autos or just manuals? thanks for the help

 

[toyman]

Ford Racing speed dial will get your speedo perfect, I used royal purple gear oil 75w90 in my rear end when I did the 4.10s

Partly true. It will depend on what drive gear is in the auto. If it is the 8 tooth gear there isn't a driven gear that is correct. However, if your auto came with the 3:27 rear gear the drive gear will be 7 tooth and the 21 tooth driven gear is spot on. Any electronic recalibration device for these cars will work as well. I also have a completely assembled Nordskog digital dash panel that can also adjust the speedo for gears and tire size changes as well as logging top speed, 0-60 time and 1/4 mile ET. It also provides actual oil pressure and temperature gauge readings. I just put it on eBay and the classifieds on Corral. It's very cool.

 

[KillNThrill24]

^THAT is freakin awesome!

 

[joekd]

Partly true. It will depend on what drive gear is in the auto. If it is the 8 tooth gear there isn't a driven gear that is correct. However, if your auto came with the 3:27 rear gear the drive gear will be 7 tooth and the 21 tooth driven gear is spot on. Any electronic recalibration device for these cars will work as well.

Exactly why I recommend the speed dial and not the gears, guaranteed to get your speedo accurate plus will last forever unlike some of the gears

 

[RichV]

Rear end oil is the same for auto/manual. IIRC I used Valvoline Synthetic with the modifier already in it. I think it was just called Valvoline LSD.

On the speedo, you just need the right gear to match the rear end. AM or CJPP sells the gears, they are a simple replacement right under the driver seat on the side of the trans. IIRC a 5/16" or a 1/4" wrench/socket and the gear pops off with a clip. Then you install the new gear.

Not sure of actual accuracy after you replace the gear. But nothing that can't be checked with a GPS app on your phone while driving.

 

[95-stang]

What a shame its not for Auto.

Partly true. It will depend on what drive gear is in the auto. If it is the 8 tooth gear there isn't a driven gear that is correct. However, if your auto came with the 3:27 rear gear the drive gear will be 7 tooth and the 21 tooth driven gear is spot on. Any electronic recalibration device for these cars will work as well. I also have a completely assembled Nordskog digital dash panel that can also adjust the speedo for gears and tire size changes as well as logging top speed, 0-60 time and 1/4 mile ET. It also provides actual oil pressure and temperature gauge readings. I just put it on eBay and the classifieds on Corral. It's very cool.