RPM on the highway ?????

[waterdog]

recently i plugged a tachmeter in my 712, and was seeing 3000 RPM at only 40 MPH (5TH GEAR)...i was wondering.. are you guys hitting redline to keep up on the highway at 55MPH or what??

[Jimm391730]

Yup, in a stock 712, redline is right about 60mph with common tire sizes. I did this for probably around 20,000 miles before changing to the turbo diesel tranny (where 4th gear is the same as 5th in the stock tranny, 1:1 ratio, and 5th is overdrive). As long as you use good oil, keep it full, and I occasionally used lead substitute (may not be necessary) I found no significant wear or issue from rpms at the high end. I ran several multi-day cross country trips on the highway where I ran hour after hour in the upper 50mph range.

Full disclosure: my engine had bad oil consumption since I bought it, needing to add a quart of oil every 3-400 miles. After being properly rebuilt by Jim L. (with 2.7l conversion, his "torque" cam grind, and replacing carbs with EFI) I also swapped in the TD tranny. The overdrive is a bit steep (I would prefer if it was half to 2/3rds the ratio) but gives about 3k rpm at 60mph. After many tens of thousands of miles since, still runs as good and oil consumption is maybe a quart every 2,000 miles. Seems that as long as you don't break anything from overspeed or otherwise, these engines are TOUGH.

[waterdog]

interesting..... thank for your reply.... running 4,5 hours trips at high RPM was my concern

[Jimm391730]

Drive on up, I'd be glad to take a look at it...

[Haf-e]

You also can swap the 712 t-case for a 710 t-case (or perhaps just swap the internal gears) instead of going to the TD-Pinz tranny.

In my 710 with 33" tires (255/85-16) the redline is about 70 mph and so I sit at about 60 mph and 3800 RPM most of the time. Not that much different than some air cooled generator engine application which often run at 3600 RPMs all their life.

[waterdog]

Drive on up, I'd be glad to take a look at it...

it would be nice to do a long drive on this vehicles,,BUT with earmuffs,,,, , but on the other side im always alert for a problem,, you never know when something may go wrong with earmuff is like driving a CADDILLAC

[Twin Pinzies]

In my opinion, driving a Pinzgauer at highway speeds is FAR harder on the truck than actually four wheeling with it.

[waterdog]

imagine to drive several hours to go four Wheeling !!!!