Tall final drive on 79' 300SD

[cambyses]

I just bought a 79' 300SD and I am fairly sure it has a shortish diff ratio.The tachometer showing around three thousand rpm@ one hundred klicks.I had heard that there was a taller final drive available and would consider having it installed if I could find the taller ring and pinion.Can anyone help me on this?Thank you all!

[t walgamuth]

it does sound like you have a short gear in there.

the normal ratio for a turbodiesel is 307. later ones were 288. some folks really interested in maximum fuel economy have put in the 247 from the big gasser cars.

the internals were interchangable for many many years, but the external mounting changed in the mid eitghties or so so you need to find which years will bolt in precisely. brian carlton and others will know the years.

when you change it you will also need to change the speedometer to get corrected readings.

if you get the correct parts it is not too hard a job, i understand.

good luck.

tom w