trying to figure out rpms at 80mph?
 

Got a 91 2wd pickup and no tach obviously so i really would like to know what kind of rpm's the motor is throwing out at 70, 80 mph etc.. I don't see any id tags to figure out what rear gear ratio i have. Any clues? thanks..

Did you check the driver door post for axle and trnasmission codes?

yeah there are none...

Get a digital tach, hook it up, drive 80? If it's stock, I think youre pulling somewhere near 3000-3100. Least that's what mine is.

Then check this place out and fill in the known info.
http://www.4x4cyberstore.com/website/rpmchart.html


My guess is you have 4.10 gears, though 2wd, I dont know if they came with a lower gear.

3K for me is just below 70.

Well according to that calculator my 4Runner has 4.88 gears, I have 31x10.50s on it and at 70mph my tach is reading about 3000RPM. I was thinking I had 4.56s but when I punch in 4.56 gears the RPM it tells me is lower then what I'm actually doing, when I punch up 4.88 its right on the money.

Hmm guess I'll have to jack it up and count. I know its open diff thats for sure. I have a 90' 3.0 Runner with 5speed tranny, and 31" factory option. I was assuming 4.56.

Most likely 4:10s