Hi everyone. I have a question about my '92 F350 crewcab. It's a SRW, 5.8L, with the 5-speed manual transmission and 4.10 gears. The truck is the base Custom model, so it does not have a tachometer. I've had it long enough now that I am starting to learn its various quirks and whatnot. I don't normally drive it in 4th gear all the time, but I took it on a mini-test run pulling our camper the other day, and I noticed that it really doesn't like pulling it in 5th gear. No problem, right? I simply dropped it down into 4th gear. Fifth gear is supposed to be an overdrive gear that's not really designed for use while towing anything, right? BTW, the camper only weighs about 3600 lbs. The only thing I noticed is that it seemed like the truck was winding out kinda high if I tried going any faster than 55 while in 4th gear. I had plenty of pedal left, so it's not like I was close to flooring it or anything like that, but it did seem like the RPMs were higher than I thought they should be. How can I, without a tachometer, figure out what the RPMs are at any given speed in any given gear?


BTW, I think this truck really sucks in terms of maneuverability when towing a small trailer like mine. Trying to back the thing into my driveway gave me a fit, so the camper is now in my back yard. I had the whole bleepin street blocked at one point while trying to back the camper in. It's a totally different experience from what I am used to with a standard cab truck. You wouldn't think that those extra couple of feet in truck length would make that big a difference, but they do when it comes to backing a trailer.

On a more positive note, I love the way this truck rides going down the road. It doesn't feel like a truck. It feels more like riding in a smooth riding comfy van. Everyone in the family likes going for a ride in the new t-ruck!

 

Here you go.

Speed versus RPM calculator

-Rod

 

Sorry it took me so long to get back to this thread. I needed to find out what the radius of the back tire is and I kept forgetting about it. Anyway, according to the calculator, my 5.8L engine is turning 2100 RPMs in 5th gear @ 60.4 MPH. That more than explains the 14mph I am getting and eases my mind about the engine winding out too much. Thanks.

 

Your getting 14mpg with a 1 ton crew cab 351 truck??????



And i'm getting 14.1mpg with my 89 F150 2wd Reg. cab 300 Straight 6!

 

I don't drive it hard, John. I am sure that explains the MPGs. I can't wait to see how much it drops when I tow the camper.

 

My 14.1mpg is driving like a grandma! Taking off from a stop real slow, and not over 55mph on the highway.

I just calculated that last week, was about 95% highway driving.

 

I don't know. That kinda surprises me. Every 300/6 I've had that had a manual tranny behind it got no less than 18 avg. Is your truck full time 4WD?

 

It's a 2wd, C6 with 3.55 gears. lol