2nd Gen Non-Engine/Transmission rear gear change

[982500]

hello everyone, this website is awesome,i just bought a 98. 5 24 valve 2wd quad with 88k miles love the truck so far it had 4. 10's when i bought it but i'm towing about 6k lbs of race car and trailer most of the time so i swapped them out for 3. 55"s what do i now have to do to get the speedometer to read right? using mile markers i get about 58 mph when i read 60 and according to the odometer my milage went from 17 to 15. 5 so thats not right either what do i h

ave to do? anyone need a set of 4. 10"s thanks mike

 

[jmeehan]

Welcome aboard. To fix your speedometer/odometer Rickson Truck Accesories sells an electronic box that'll plug into your harness and correct the readings. I think they're at rickson.com, or you can find them in the links section under wheels and tires.

 

[Turbo Tim 1]

If you've retained the stock size tires you can go to a dealer and have them reprogram the PCM for that gearing.

 

[jmeehan]

Originally posted by turbo tim1

If you've retained the stock size tires you can go to a dealer and have them reprogram the PCM for that gearing.

DOH! Sorry, I forgot about that simple fix... I just finished looking at the Rickson site and it stuck in my head.

 

[Big White Beast]

I know on mine.........

A 2001 the speedo is run from the carrier in the rear end. After the swap the speedo ran true without any adjustments. Not sure on your year.



If your only off by 2 MPH I wouldn't even worry about it. New tires compared to worn tires could make that much difference.



Garrett

 

[982500]

thanks for all the replies everyone, BIG WHITE the speedo does read from the rear carrier but also from the trans, so the reading from the ring gear doesnt change but the driveshaft is now spinning slower so i wonder if the pcm needs to be reprogramed? thanks mike

 

[RobertYoung]

It's time for a rear gear change, I now have 410's , can I go higher? I pull a 14,000 lb 5th wheel. Would 373's work?

Plumb Bob