Well I've had this 1/2 ton for 3 weeks and got the brakes fixed, fortunately.
Anyway I put new 215-70-15R tires on it, all 4. Also I put on a Tach, set for 6 cyl. setting.
So I took it out on the Interstate and found the speedometer was a bit off. Like I have to indicate about 67-68mph to do a mile in 60 seconds, averaged over 10 miles, steady(as possible). Anyway at that speed it is Tach-ing about 3100 rpms. So I took it up to where I was doing miles in about 51 to 52 seconds, which would be around 70 mph. At that speed I was Tach-ing 3600 to 3700 rpms. The speedometer at that speed was showing 78-79 mph.
Anyway, At 70-ish mph it is really working hard or it sounds that way. Also, for a 153 mile trip, I got only about 11.5 mpg, having been very careful about filling tank both going and coming back. Also, the Odometer runs about 12.5% further than the actual distance I've gone.
No tag or markings on the differential I can find, cleaned and looked. Wondering if it is a 4.11 or 3.73?
Thank y'all for help.
