Speedometer issue

[Fant]

I bought what was told to be a 85 bronco np208 tcase.after research turns out it is an 82 full size np208. The speedometer gear was still in it. They had cut the cable. Thing is when i drive down the rd at 50-55 my speedometer reads 75 or so. Im wondering if they put the wrong gear in this case. I took my stock gear off frm my borg warner. And used the gear they had in the np208. And the speedometer in the cab wines like crazy cuz its turnin so fast. How would i find the right gear to install on my cable for this tcase to get me closer to actual speed of travel?? I still have gear for borg warner tcase. Should i try it?im lost on this as ive never messed with this before. And i need a speedometer as this truck is on hway alot

 

[Fant]

image.jpg (100.4 KB)

 

[Fant]

Thats the tag on my np208. Shows 82 on yr. 2.61 on ratio. Im running 3.73 gears on rearends and 33x12.50x15 tires. When i had my stock setup(2.8v6 and bw1350 or 1354) my speedo was real close. And it didnt jump or act all crazy. All i changed was went with longer cable frm speedometer in cab. And put gear on the end that was already left in tcase. Now my speedometer jumps around between 5mph differences when driving. And shows 70-75 at 50-55 mph. And makes an awful winding inside the cable.any advice on a fix without dropping tcase again????????

 

[gsp]

There is an app for that, I use windshield mount on my smart phone with a GPS speedo app

 

[Fant]

Alright. Il remember that for backup plan if i cnt figure out how to fix it