Alec

This is in response to Thrashingcow's question regarding a quip I made in a hijack of another thread. I started to respond there, but it just seemed too much a breach of etiquette.

These are suggestions for transmissions other than the G56:

How about an Eaton FSO 8406A?

F series Synchronized Overdrive 860 lb/ft input rating 6 speed.
R: 6.75 1st:7.05 2nd:4.13 3rd: 2.52 4th: 1.59 5th:1 6th:.78
359 lbs dry weight, 25.6" overall length.

The FSO 5206, rated for 640 lb/ft is only 254 lbs dry, 20.5" overall length. Probably better if you aren't going to truly abuse things. I don't have the GCVWR for the FSO's right in front of me, but I am pretty sure our trucks are light enough that you would burn up all four tires before breaking the transmission.

For 4x4's there is a guy who is making up adapters for the FS transmissions to mate to married transfer cases, he has a couple working prototypes.

If you aren't scared of no synchros, then you can get into the baby RTO 6610 in the 350 lb weight range . . . Twin countershaft close-ratio (30% progressive gears) ten speed. At least one swap w/ one of these in a 1st gen, and another quite clean swap into a 2nd gen, both 4x4.

There are also the RT 6609 & RT 8609, but neither of these came stock with OD. Low 1st, then skip first after the range shift, 33% progressive gears.

But, it is probably easier just to slap in a G56.

BearKiller

There is a very lengthy thread on another Dodge/Cummins forum discussing how several members have installed Eaton/Fuller 6-speed OD units.

The 6-speeds came either 6th=direct or 6th=OD; that thread lists which Eaton #s are OD.

Some of those guys first tried the NV5600 and experienced transmission failures, thus pointing them in the direction of the Eaton/Fullers which, according to them, are bullet-proof.

Certain medium-duty Fords came with 6BT and Eaton 6-speed, both direct and OD, so this swap can be entirely done with over-the-counter parts, or by simply buying a complete donor truck that should have all one needs.


Myself, I have always wanted a 9-speed OD; nothing shifts better than an Eaton/Fuller 9-speed non-syncro.

rrgrassi

What are the advantages of non syncro vs syncro? Do non synchro's tend to grind more if you do not hit it just right? I have never drivien a non synchro, that I know of, except my old tractor.

I did drive a '77 Datsun F10 coupe, but I do not know if it was a non synchro or not.

Angry Johnny

Oh you would know if it was a non synchro transmission.

I have a class a cdl although I don't use it anymore and driving those big tractors without synchros is an art. The hardest part for me was remembering what gear I was in at times. That can get you in trouble real fast.

patdaly

Just a thread from the past...... also good info.

https://www.dieseltruckresource.com/...y+transmission

mknittle

that is the problem every time I ever tried to keep track of what gear I was in I couldn't shift for beans. When I didn't think about it I was a super smooth shifter( lots ov hours perfecting that). My favorite transmission was the fuller roadranger single overdrive 18 speed. I loved that transmission.

BearKiller

A few weeks ago, I made quite a lengthy journey in a 379 "flat top" Peterbilt with some kind of a BIG Caterpillar and 18-speed; in my many years of driving, this was my first time for an 18-speed. (Someone said it was a 2000 year-model; I have no idea)

It took me 300 miles to get it figured out; but, once I learned when which button did what, I could see why everyone loves an 18.

I am a Cummins man, but whatever it was, weighing a bit over 80,000, that big Caterpillar would easily run up behind anything else on a hill, suck it through the breather, and spit it out the exhaust, and I never really called on it at all.

I wish the headlights had of been half as good; it had four sealed-beams and they pointed in four different directions and were so dim I had to strike a match to see if they were lit. Don't get me wrong --- I very much prefer sealed-beams, but these were in dire need of some maintenance.

The bosses usual response regarding such annoyances, inconveniences, and downright dangerous situations: "We ain't got time to worry about that right now; go ahead and get out there and we will worry about that when you get back."
And, always before leaving on a run "Don't you worry about a thing; we will have it all checked out and ready to go; all you got to do is hop in and drive."
At first, I took him at his word on that statement about having everything "checked out"; but, after a few occasions of finding numerous tires almost or completely flat, lights busted or hanging out by the wires, half as many straps as I knew were in the there the last time I drove it, hubs nearly dry, dipsticks barely touching oil, etc. etc. I could go on and on, I decided that operation was every man for himself.

jimlj

Years ago I drove a crew bus to and from work with 40 of my closest friends sitting behind me. Every day you had about a 50% chance of getting the same bus. The only thing they had in common was the speedometer and tachometer rarely worked and they all had non synchro transmissions. It only took a few days to learn to hit the gears or your 40 buddys would give you chit. I learned to shift by the oil pressure gauge and rarely missed a gear.

NE frmhnd

That's as sad as the cab-over my cousin took out to get an empty trailer one day while his was in the shop. Key wouldn't turn in the ignition, and there was a screwdriver on the dash. He pulled the key and started it with the screwdriver.
That was a Schneider truck.
Never drove an 18, but rode with a guy who did. Hit every gear on the way up and down. Bobtailed. Talk about motion sickness. Probably would have got better fuel mileage skipping gears and leaving the splitter alone til he got to the top end, simply for not respooling the turbo 17 times.

I wouldn't mind a 13 speed. But no 15's. Drove that thing for a month before I started tog et the hang of the 300 RPM drop.

mknittle

That is crazy all 18 I hate the 15's and 13's aren't bad.

NE frmhnd

A 13 can make a little engine run like a big one, but other than doing a lot of work at low speed, I don't see the benefit of an 18. The 15 was a deep reduction, and even in the lowest gear, was about like taking off in 3rd with a 10 speed. With an 18, at least you can run it like a 13.

mknittle

We are loggers in the Sierra Nevada mountains. that could explain a lot. Lots of steep windy roads.

1972RedNeck

I do like the 13 speed for hauling hay/grain over the road. When we have the semis loaded up in the hay field/grain field though, the 8LL really shines. The 18 speed is the best of both worlds.

My favorite truck is our '95 International grain truck with a 3406E tuned with a heavy haul flash (550 HP & governs at 2300 RPM) backed by a 10 speed. It only holds 750 bushel so it never weighs over 75,000 lbs. Since I always drive it during harvest when everyone is in a hurry, I get to run it ***** to the walls all the time. After I made a boost fooler and fuel temp resistor wire, it's even more scary fast.

The 13 speed is by far the fastest shifting tranny we have. If you run it up to governor, once in high range you can shift gears without having the boost drop below 10 lbs.

For some unexplainable reason, all of our big Kitty Cats drink fuel like crazy whenever I am behind the wheel.

BearKiller

My neighbor that I occasionally drive for has two tri-axles with 8LLs; one is a standard pattern, the other is the "horseshoe" pattern.

The horseshoe 8LL is in the far better truck, but the standard 8LL in the other truck shifts a lot better.

I never could understand the reasoning behind the horseshoe pattern; the gears seem to be the same, just in different places; it makes for an interesting day when I have to constantly be in and out of both trucks.

The 8LL is an extreme-duty transmission that is --- from what I have seen anyway --- bulletproof, like the old 5-speed Maxidyne Macks.

Although named an 8-speed, they actually have 15 usable forward gears and three reverses.

With an 8LL, if you ever get lost in your shifting and the teeth start grinding, it is nigh impossible to find a gear without almost completely stopping; I attribute this to the spread of ratios being so close.

I do love the 8LL in deep-reduction; they give true meaning to the terms "Bulldog" and "Granny Gear"


At the end of a long day, when I get in my F350 to head home, I nearly push the clutch-pedal plumb through the floor-boards and can't find reverse until I realize I'm not in a big truck anymore; and, as tall as my F350 is, it feels like I am sitting in the road.

mknittle

Up until I tore my Dodge down I still reached for the nonexistent stick to shift up a gear and the Jake Brake switch