Crusing RPM's

[Elwood P Dowd]

I've got a 2000 F350 with the 7.3 and a automatic, at 70mph I'm running just below 2400rpm is that about right? It sounds a little high while I'm in the truck but it could be that I'm just not used to driving diesels. Just wondering what everyone else was running.

[burrfree]

You must have 4:10's. That would be about right.

[Elwood P Dowd]

Originally Posted by burrfree

You must have 4:10's. That would be about right.

i dont suppose that Ford would have been kind enough to put a tag on the rearend that tells you what ratio it is would they? Guess I'll go out and take a look

[chrispaine]

my truck runs right about 2000 @70mph I want a gear vendor, maybe I could get it to around 1600rpm..

[Fred Swanson]

Yes there should be a tag on the rear end passenger side of the differential, this will state the original gear ratio, the tag on the drivers side says synthetic lube....Fred

[Cutty72]

I ran about 2400 the other day pushing 78-80.

[GIMAMMOTH]

Gear Calculator USE THIS TO HELP YOU OUT

[GIMAMMOTH]

4R100

Gear 1 2 3 4 R
Ratio 2.71:1 1.54:1 1:1 0.71:1 2.88:1

5R110

Gear 1 2 3 4 5 R
Ratio 3.11:1 2.22:1 1.55 1:1 0.71:1 2.88:1

5 Speed Manual

Gear 1 2 3 4 5 R
Ratio 5.72:1 2.94:1 1.61 1:1 0.76:1 5.24:1

ZF S6-650 transmission

Gear L 1 2 3 4 5 R
Ratio 5.79:1 3.30:1 2.10 1.30 1:1 0.72:1 5.24:1

HERE ARE YOUR TRANNY SPECS

[Jarrod B]

My 99 with 3.73 auto runs at 2k @ 70 mph
My 97 with 4.10 auto ran at 2200-2300 @ 70mph

Our 88 with 3.55 manual runs at 2200-2300ish @ 70mph

[scraph]

Just a reminder ... tire diameter comes into the equation ... as well as whether or not the speedometer has been recalibrated for a non-stock tire size.