c-6 or e4od for durability/fuel economy

[89Laredo]

Was that a diesel t19, or did you buy bellhousing and trans separate? Cause there was never a NP435 behind a Ford IDI from the factory, but I made mine like that, everything was a bolt-on affair. If you can tell me your road speed at say 2000 engine RPMs in 1st gear I can tell you your transmission gear ratios. Will need to know brand and size of your rear tires also, and axle ratio. Would be interesting to find out, as I had a diesel-specific t19 and first gear was quite usable when empty (and fairly useless when loaded down heavy), what you're describing sure sounds like a creeper 1st to me as that's how my NP435 behaves. Btw if you swap in a newer Sterling you can have both rear discs and a limited slip. Tho there is only so much a factory LSD can do, I've had mine stuck several times pulling a trailer thru mud/clay where one side is spinning and the other just sits there looking all pretty like

Don't have a tach. Guess I could hold it to the floor and tell you indicated speed at the governor.
The truck is a factory 4 speed but not sure it's the original trans. I'm assuming it is though.
I shouldn't say "useless" but it's definitely a pretty low gear.
Seems to have a big gap between third and fourth too.
Keep in mind this is the first manual trans I've owned/driven.

I was going to swap the 10.25 out of my 85 into this truck. I did a disk swap on it a couple months ago. This truck currently has a 3.55 LS D70U.
The 10.25 is open, but I was considering a lunchbox.

 

[Clb]

Doubled cases with 4:7's in back! That a final drive ratio! The bellhousing to output is round 4' long

 

[Clb]

Omg! This thing is awesome the ats and zf' whoohoo
Pics later just rolled in from la!
Miller time!
Thanx guys!

 

[The Warden]

I shouldn't say "useless" but it's definitely a pretty low gear.
Seems to have a big gap between third and fourth too.

That sounds like my old T-19...in 3rd, I'd be getting close to the governor at 35 mph, but would lug the engine if I upshifted to 4th at 35 mph. Made climbing a hill with a load a less than fun task. I wouldn't say that 1st was a granny gear, but it was really only usable for getting started, and I could have started in 2nd if I wanted to. That's with an '84 (August '83 build) truck and the factory transmission. I was never happy with the gear spacing on this transmission; ended up swapping a ZF5 in and have been much happier.

I drove an '86 with a T-19 once (AFAIK factory, but wasn't my truck), and the gear ratios were definitely different...the gap between 3rd and 4th was significantly less, and the gear ratios in general felt much better-suited to the 6.9l's power band. It was almost as good as the ratios on the ZF I have in my truck now

There are differing schools of thought, but after my experience with what probably wasn't a true wide-ratio T-19, I would not want a wide-ratio transmission without a gear splitter.

JMHO...

 

[89Laredo]

That sounds like my old T-19...in 3rd, I'd be getting close to the governor at 35 mph, but would lug the engine if I upshifted to 4th at 35 mph.

yes.
I shift to 4th at ~40 and it still lugs a little.

 

[The Warden]

yes.
I shift to 4th at ~40 and it still lugs a little.

Yeah...no fun at all. By contrast, with the ZF, I can get to 50+ mph in 3rd gear if I need to...makes holding speed on a grade considerably easier

 

[Clb]

the 173:1 is at the wheels.... 5 gear 228:1 doubler(stock yota) 4.7 lows in t case

 

[Clb]

Yeah...no fun at all. By contrast, with the ZF, I can get to 50+ mph in 3rd gear if I need to...makes holding speed on a grade considerably easier

do ya tow much? if so how heavy and what mileage do ya get?
yer at my elevation.

 

[The Warden]

do ya tow much? if so how heavy and what mileage do ya get?
yer at my elevation.

Probably 50% of of time I'm driving my truck, there's a trailer strapped to it...my truck's not my daily driver. Seems like most of the trailers I've been towing have been in the 6K to 8K range (I volunteer with a youth group, so I don't own these trailers myself). Here's an example of a boat I tow on a fairly regular basis; this weighs just shy of 8K.

You must be registered for see images attach

As for fuel mileage...I average 14 to 15 loaded and 17 to 18 empty with my truck in its current configuration (ZF5, stock tires, ATS 088 non-gated turbo, lumber rack removed). That's mostly in the Bay Area or up the Delta. I'll say this...going up the Altamont Pass with that boat strapped to me got me down to 40 mph or so in 3rd and killed quite a few mosquitoes

 

[Clb]

Nice , is that an old navy boat?
Gotta do some work on mine , towing 5k it goes from 14 to 8???! (Read mad)
Thanx cb

 

[The Warden]

Nice , is that an old navy boat?
Gotta do some work on mine , towing 5k it goes from 14 to 8???! (Read mad)
Thanx cb

That's with the ZF?!? YIKES!!! My first instinct is that the fuel system probably needs to be gone through...injectors, pump, get the timing set. Second...what size tires are you running? If they're wider than stock, that'll sap your fuel mileage. Beyond that...synthetic in the transmission, transfer case, and rear axle will help...and, of course, there's driving style.

Granted, I've been accused of driving like an old granny but I've actually broken the 20 mpg barrier on a highway run down the I-5 to L.A. That may be an outlier, but with a ZF, even with 4.10's, you should be capable of high teens empty. I used to get 14 mpg on a regular basis when I still had the T-19 in my truck

 

[Clb]

Yep
The truck in the one in my new sig line, its got 38k factory(sat alot tow rig only) left la up 5 cc set at 75 got at 14-14.5 over the grapevine! The c-6 4:10 early banks 1988 with new delphi's and moose jr. Towing to/from the house to the coast got a best of 9. Up from7.5 before the pump/inj.. This is 093 stock ip/ inj. Timing unknown as the new bb's and junior are ready to install' so I have waited to bug my bud to use his meter!
Same trip, same driver, same load!
I am begining to miss the old 12 v

 

[The Warden]

Nice , is that an old navy boat?

Oops, just realized I didn't answer this question earlier...yeah, it's an old Navy motor whaleboat. Has a small 4-banger Perkins diesel powering it. It's a nice little crew boat...and, here's our primary training vessel:

You must be registered for see images attach

95" Cape-class retired USCGC cutter

Yep
The truck in the one in my new sig line, its got 38k factory(sat alot tow rig only) left la up 5 cc set at 75 got at 14-14.5 over the grapevine! The c-6 4:10 early banks 1988 with new delphi's and moose jr. Towing to/from the house to the coast got a best of 9. Up from7.5 before the pump/inj.. This is 093 stock ip/ inj. Timing unknown as the new bb's and junior are ready to install' so I have waited to bug my bud to use his meter!
Same trip, same driver, same load!
I am begining to miss the old 12 v

Those 12 valves are definitely nice...I will find a way to own one someday

Let me make sure I have this correct...you're saying that you got 7.5 to 9 mpg with the C6/4.10 truck? That actually doesn't surprise me, especially towing...the C6 is pretty bulletproof, but with no lockup converter or overdrive gear, it's NOT the most efficient transmission. Honestly...I plan to run a ZF until my left leg falls off, but if I'm ever forced kicking and screaming into a slushbox, I'd shell out the money to overbuild an E4DOA (it IS possible to make then reliable, if you spend enough $$ ) before running a C6, even with an aux overdrive. THe torque converter lockup is worth it IMHO.

For what it's worth, I used to own an '84 E-350 van that had a 6.9l, C6, and 3.54 gears, and even with that setup, I averaged 13 mpg. I don't remember what size tires the van had, but they were wider than stock...I never experimented with changing rims and tires, but I remember the previous owner saying that he got 17 mpg before switching to the wider tires.

With that said, 14 to 14.5 mpg going over the Grapevine at 75 mph doesn't sound too bad, all things considering. I usually sit between 65 and 70, leaning more towards 65...between the mountains and how much sail area these trucks have, I could imagine that much of a dip in fuel economy. It's really amazing how much right-pedal handling affects fuel mileage in any vehicle, but especially in one of these trucks! And, I'll bet that renewing the fuel system will help...even with only 38K miles on the odometer, the truck's been sitting long enough that things could certainly have degraded with time...

 

[Clb]

On the boat' I thought so!
Just flat out old world craftsmanship .
We have the chaser up here in the napa river looks about the same as your cutter.
The 88 was an animal it did everything I wanted cept' get mpg' now the downgrade performance with an open converter
The 93 was bone stock, has an 093 (non ford) on it 3" dp into stock after pipe.
It looks like the install was done by the book' as it was gated at 5 psi!
I put in gauges first, saw it go flat half way into a grade the 88 would eat alive' 5 psi maybe 8-900*...then went after the gate, the pump must be set at an optimal setting cuz mow it will spin up to 12# at 1050-1100* on the same route.
Brandy new highway tread( sized off the vin tag) aired up right, flat top 5er ( low sail factor) I keep the turbo spooled and pull at around 3200 on grade .
I would be a happy guy if the timing and new fuel setup adds 5 mpg on the towing #'s but seriousley dought it
This rig pulls just fine looks great, rides good but 8 pulling I dunno!
I agree about the left leg thing, a full tilt electric slushbox would cost more than my 88 cost me but it would work!

 

[The Warden]

On the boat' I thought so!
Just flat out old world craftsmanship .
We have the chaser up here in the napa river looks about the same as your cutter.

Yep!! I know the Chaser well and have spent some quality time at their base in Napa (they host a mini-competition every fall)...I've always had a great deal of respect for Skipper Shellhorn. Their boat's a 90 footer, and I think she used to belong to the Department of Fish and Game, although I could be remembering wrong. She originally had two Waukesha main engines, but parts were so hard to come by that they repowered her with Caterpillars a couple of years ago after cracking a liner.

I'm with a different unit in the same program...Sea Scout Ship Challenger #145, based out of Redwood City. I joined at age 12 and still volunteer with them when I can (difficult since my current job has me working weekends), but I take a great deal of pride in the program. For that matter, we've had the 95" since 2005...the first boat my unit ran (1994 to '98) was named Warden Johnston, which is where my handle comes from

Actually, I could be wrong, but I think the Chaser might have one of these whaleboats too...there are three of them floating around. A unit in Stockton had them, but they were forced to give up their base and had nowhere to store the boats, so they gave them away to three other units. We got one, and I think one of the others went to the Chaser, and I'm not sure where the third one is.

The 88 was an animal it did everything I wanted cept' get mpg' now the downgrade performance with an open converter
The 93 was bone stock, has an 093 (non ford) on it 3" dp into stock after pipe.
It looks like the install was done by the book' as it was gated at 5 psi!
I put in gauges first, saw it go flat half way into a grade the 88 would eat alive' 5 psi maybe 8-900*...then went after the gate, the pump must be set at an optimal setting cuz mow it will spin up to 12# at 1050-1100* on the same route.
Brandy new highway tread( sized off the vin tag) aired up right, flat top 5er ( low sail factor) I keep the turbo spooled and pull at around 3200 on grade .
I would be a happy guy if the timing and new fuel setup adds 5 mpg on the towing #'s but seriousley dought it
This rig pulls just fine looks great, rides good but 8 pulling I dunno!
I agree about the left leg thing, a full tilt electric slushbox would cost more than my 88 cost me but it would work!

If the fuel system's in bad enough shape and especially if the timing's a mile off, I could see you gaining a fair amount...5 mpg gain may be optimistic, but with "only" 5K behind you and not having a ridiculous amount of sail area, 8 mpg is absymal. Dumb question, but how full do you fill the fuel tanks? I'm pretty ****...I top both tanks off to the point where I have fuel right at the top of the fillneck. Given how inconsistent diesel pumps tend to be with clicking off, IMHO that's the only way to get a truly accurate fuel economy calculation. Might not be a bad idea to do this for a few tanks to get a good baseline for how you're doing.

With fuel mileage that low...you might want to make 100% sure you don't have any brakes dragging on the truck or trailer, and make sure the wheel bearings are happy especially on the trailer (a commonly ignored maintenance item). I still suspect that the fuel system could stand to be refreshed, and again, doing synthetic in all of the gearboxes and axles will benefit as well, but the more I think about it, the more I think there may be an additional issue...that boat's about 8K with the trailer and tows heavy even compared to other trailers that weigh about the same, and I STILL get 13 to 14 mpg with it...