Rednecktastic

The truck is a 1998 12V 5 speed. I'm wondering if I should equate 20% more miles into the odo reading. I guess my question is does it pick up the speed reading in front of the gear reducer or off it?

Mileage is a little on the high side of what I am looking for but everything else is literally right on spec even color.




Thanks for the help, my mind is set on buying a clean 12V for my work truck but I need it to last me which is why I'm buying a Cummins . I hope to be visiting this forum more with questions.

infidel

'98 12 valves are are whole different animal from the way earlier 12 valve electronic systems are set up.
They're more like a 24 valve.
email US Gear and ask info@usgear.com

Rednecktastic

No, it's a 98 quad cab 12V just like I want.


Thanks, I'll shoot them an email.

BigErksG2

The odometer should be accurate as the speed sensor is at the axle not on the transmission, so the speed of the driveshaft going into the rear does not change because the gear splitter is before it.

Rednecktastic

oh wow that's awesome thanks man!

infidel

I wouldn't be too sure about that.
I'm almost certain on a '98 the tranny sensor feeds the odo and the rear axle sensor is only for the ABS.

Rednecktastic

oh ok, so the 98 12V and 97 12V would pick up the speed at a different place possibly?

iker42

our 98.5's speed sensor is on the axle, im assuming its the same for the 98
Yes

Rednecktastic

Ok, so all 98 trucks pick up speed from the rear axle even if they are a 12V.

infidel

Ok, here's what I know about '98 12 and 24 valves.
They both have a sensor on the tranny (t-case on a 4wd) and the differential.
The tranny sensor feeds the the speedo and odo and the differential sensor feeds the ABS.
But if the differential sensor isn't working correctly speedo doesn't work under 30 mph.

All rear wheel ABS equipped trucks have a speed sensor on the tranny and another on the differential. ABS records the difference between the two readings and knows when to activate the ABS.

Rednecktastic

Ok, thanks man. I think i'm going to pass on this truck I'm looking at because if I add 20% to the miles it's way over what I want.

mprmnc

Where's the truck, I'd be interested considering my 98 12 valve doesn't even have a place to put a speed sensor on the transfer case. The hole where the speed sensor goes wasn't machined. The speedo IS run by the ring gear on the 98's.

sjester

If you own, or can borrow, a GPS you could check the speedo/odo for accuracy on a test drive, although a 20% difference is huge and you'd most likely be able to tell by how long it took to get up to an observed 60 MPH I would guess

12valvedave

ihave a us gear splitter on my 97' 12 valve and it does not affect the speedo. because the sensor is on the output shaft of the transfer case, and thus is sensing output shaft revolutions. these remain constant because the us gear is between the trans and transfer case. hope this helps. p.s. the us gear is a great unit i have 3.54's and cruise at 75mph at 1700 rpm.