1124.5 342You need to reset the "dip switches" in the top of the cluster head of the General Instrument speedo cluster.
Make sure you turn the ignition OFF and watch out for static electricity jolts, too!!
tire rev's/mile = A
axle ratio = B
A x B = revs/mile of the prop shaft.
My truck: revs/mile 12/22.5= 485 rev/mile
Axle ratio = 5.38
485 x 5.38= 2609
2609 dipswitches set to 0011101010
If you have the linesetting ticket, IH puts them on there, too!
Just give me your tire size & rear ratio & I'll do it for you.