Hey guys am I missing something? (3.54 rear end gear ratio) With the auto I could top out around 90 with more room to spare. Now with the getrag the truck is screaming around 45 in 4th and 65 in 5 so I pretty much always have to use 5th which I was hoping wouldn't be the occasion. I told the trans shop(trans gear performance) my gear ratio. Although it's a bit tough to hear the engine because I haven't closed the floor yet still waiting for my shifter boot to arrive.

 

Keep in mind this is according to google maps because my speedo says im going 90 while google maps says im going 60.

 

Use Google maps speed and the radar cop will let you know if it's right.

 

Probably a different speedo output on the trans. The getrag usually has a right-angle gear reducer before it goes into the speedo widget.

Edit: did your auto have OD? If so, its OD ratio is taller than the 5spd.

 

Thanks man this really clears things up yea my a518 had o/d. The overdrive failed which is why I did the swap do you know where I can find the correct gear reducer?

 

The factory ones are on parts trucks.

You can google for generic ones, like here:
https://transmissioncenter.net/shop/...-888-201-2066/

But you need to know how far apart your actual speed and speedometer are to choose the right ratio.

 

Alright so if my speedo says I'm going 92 while google maps says I'm going 62 which one would I need?

 

Best way to figure out exact speed is to have someone pace you in their vehicle with a known good speedo. You do 50 mph and they match your speed and then let you know what speed they were doing, then it's some simple math after that to figure out if your need an increase or reduction ratio adapter.

 

Speedo says I'm doing 98 while I'm actually doing 63.

 

divide one number into the other.

1: 0.674
(Input: output)

 

I contacted patc they got it straightened out just waiting for the adapter to arrive.