Does anybody here have an educated guess as to what my fuel mileage should be with the 84 dually I just picked up?

4.10 rear, 3 spd auto trans. 6.9L w/ Banks Sidewinder



Also, since I'm learning...what additives should I consider for the oil, coolant, tranny...etc.?

And the previous owner said I should get some anti-bacterial treatment for the fuel in the rear tank since it's been sitting so long... HUH? What? Where? I have some antibacterial hand soap. LOL

Like I said, I'm a noob. But I want to learn!

 

Moved to diesel engine forum.

 

Ummm...just out of curiousity, exactly where IS the "diesel engine forum"?
The 1984 truck he's talking about is a "pre-power stroke"...so where else should it go?

Lobstah

 

The popular choice seems to be Stanadyne for fuel additives, followed closely by Walmart's brand, which I think is Power Source or something. I haven't found any Stanadyne here in my area, so use the Walmart stuff. The anti-bacterial stuff is basically for when diesel sits for extended periods of time. Was this due to a problem he already experienced with your truck, or was he just being cautious? I used to run a fungicide in the fuel tanks on my boat, but that was because I had 400gals in tanks, and would only burn about 200gals in a season, so the fuel was pretty stagnant. Unless there's no problem now, the chances are pretty slim of you getting bacteria growning in your fuel tanks. If it was specific to the rear tank, and you can't find any at your local NAPA or CAP, go to a marine supply store like West, they'll have what you need.

I don't run ANY additives in my oil, and don't think most other people do either. I DO run a good quality oil, and would be pretty religous about changes. Rotella is a popular brand...I run Delvac 1300 in mine.

If you're towing a heavy trailer, most recommend running a synthetic gear lubricant in your rear end, as they're less prone to heat breakdown.

As for mileage, other posts from guys with 6.9s and turbos, I'd be looking for somewhere in the 17-19mpg range...but ONLY if you can learn to keep your foot out of it. Me...I pretty much love the sound of that motor, and could care less if the mileage varies a bit one way or the other. I've spent a LOT more money on things that were a LOT less entertaining, and yes, that would include my first wife

Enjoy the truck, and welcome to the forum.

Lobstah

p.s. You don't REALLY need that Banks, so I'd be happy to take it off your hands for you It's really just something else that will break...eventually...

really.

 

Hey Eric...
Just figured out what you meant...DOH!
Thought it was being moved somewhere ELSE, not FROM somewhere else...lol

Keep up the good work.

Lobstah

 

REALLY? Even with the 4.10's and a 3-spd? Man, that would kick ***.

I'm considering changing the gear ratio, as my camper only weighs 6300 lbs fully laden. I gotta think that the 4.10's will be more of a drain on the mpg than the weight of the camper. I'm thinking maybe a 3.55 or 3.80something would be a better ratio to have. I also want to install a tach, since this truck does not have one. 4.10's just seems like it would scream at 70mph.

The fuel in the rear tank has been in there for almost a year. The truck was sitting cuz it needed king pins, and they guy couldn't get the old ones out. ( I have no idea what his problem was...I just did the king pins last night and it was a piece of cake.) So he said I may want to add something to that tank.

Also, the tank switchover isn't working. Regardless of where the switch is, it only pumps from the front tank. So I guess I hafta clean or replace the solenoid.

 

yeah...sounds like either the solenoid or the valve could be stuck. Forgot about the 410's, you're right, that may be a little steep. Just have to run it and see.

Lobstah

 

Hey Lobstah, I see we basically have the same truck!

What gear ratio do you have in yours? I'll trade ya the Banks Sidewinder for your gears!

LOL

 

Now that's a DEAL...lol

I could use steeper gears then whatever is in there now...

Hills pull me down to about 30mph when I'm towing the 5er.

Lobstah

 

30 mph...ouch. Maybe I'll keep the 4.10's and see how bad it is. The rear is brand-new...so it would be a shame to gut it.

Do you have a tach on your truck? I need to find out how to install a tach... What do you mean there's no distributor? LOL

 

BTW...was thinking about your fuel tank/fungicide deal yesterday. If there's already bateria growing in it, could be too late. If it's NOT growing, probably don't need the fungicide, if that makes any sense?
If it DOES have algea in it, I'd imagine it'll clog up the fuel filter pretty fast, and by that time, I think you'd have to drain/clean the tank. At least that's what had to be done on boats.

Lobstah

 

HrlyDr,
I had the same problem with the fuel tank switch. In my case, there were 2 problems:
1) The electrical connector on the actual electric valve had deteriorated from guess what; diesel fuel.
2) There was a blown fuse, which may have resulted from the repair effort regarding #1.

Good luck,
Al

 

The best, I repeat ... the best advice I can give u for mileage improvement is to put a Gear Vendors Overdrive on your rig.
My older rig 1985 F250 Super Cab 6.9 Gale Banks sidewinder
Big exhaust, C6 with GV overdrive, now the load, 45 gallon rear tank, stock front, 2 15 gallon saddles, 8' camper, 23' fiberglass cuddy cabin w/ 105 gallons of gas plus 4 - 18 gallon drums on the deck, 3 men and lots of boat electronics and fishing gear. Can drive from San Diego to Cabo San Lucas w/o refuling. Keep the exhaust temp resonable and the rpms right and it will pull it all.
BTW 196,000 miles on the rig and would not hesitate to do the trip again. Overall average mpg is 12 with the above load.

 

I'm not sure what tranny I have...but it's only a 3 spd. It's new, the last owner just had it put in...I think he got it at Advacne Auto. Orginally I thought it was a Jasper, but it's not.

Anyhoo... GV overdrive? And I've seen in the other thread where you mentioned a gear splitter...I've seen those on some other trucks, where do you get one? I'm assuming it's not a factory option.

EDIT

Ok, as best I can tell, I have a C-6 trans.

And I just realized that Gear Vendors is the company name. I might be able to justify the cost, if my trans wasn't new, and if it didn't cost almost as much as the truck did.

I'm hesitant to start spending money on an unproven vehicle. I'd like to have some serious seat time in this rig before I start spending $. I have no reason to believe it won't be a reliable truck, but proof is in the pudding. Maybe I'm overly cautious.

My plan is to work out all the minor bugs in this truck, then do the minor bodywork (surface rust in a few spots) & paint that it needs to make it all pretty lookin. More than likely, I'll be looking seriously at a newer truck in the next year or two, but if this truck serves me well, I'll keep it. After all, it's paid for, and it was a helluvalotta truck for the money IMO.