I have a t5 transfer and I and installingva 145 speedometer.

Do I need to swap out my speedometer drive and driven gears?
or
is the difference for the MPH is preset within the speedometer it's self? ?

Sorry if its kind of a noob question

 

i'm assuming you mean you currently have a t5 and your installing a 145mph speedo?

the transmission drive and driven gears are matched for the rear axle ratio gears to drive the speedo.

so yes, you can put in a 145mph speedometer without changing them

 

Yes that's exactly what I ment.

So just swap them out and I'm good

Drive n drive gears only change when tires/gears change correct?

 

Right: the speedo sill wants to see 1000 turns of the cable per mile. None of that changes.

 

Often the trip odometer is broken. If so, and it's important to you, the following link provides a fix:

https://www.thirdgen.org/forums/faq-...-fix-pics.html

JamesC

 

And post 56 even nicely addressed the primary question of this thread.