Darryl&Rita

Not a truck driver, barely even pretended as a kid. I'm wondering if anyone has opinions on the order, from best to worst, of manual transmissions in big trucks. I see lots of 18 speed around local, but see 13, 10, and 9 speeds on e-bay, racing-junk, etc. I don't know much about any, synchro vs. not and much more. Please enlighten me

wannadiesel

None of those transmissions are synchronized. If you have a feel for machinery you will not have much trouble learning to operate any of them.

They are all basically huge 5 speed transmissions with an auxiliary gearbox or gearboxes. You run through the normal 5 speed shift pattern, flip a switch on the shifter, then run through the pattern (or part of it) again. Some are shifted differently but you get the idea.

The more "speeds" the less RPM change per shift. 18 speeds are usually found in highway tractors. 9 and 10 speeds are found in lighter local use tractors and in dump trucks, 13's are kind of the all-purpose tractor trans.

"Best" depends on what you are using it for, each one is the best choice for a particular application.

Darryl&Rita

Good point. I'm looking into upgrading from a SRW 3500 megacab to a heavy truck. It will be used to possibly carry a Jeep LJ (think long wheelbase TJ), and pull a 5th wheel grossing around 12-15000 lb. Unless pricing comes down, it would seem unlikely that an auto-shift is in my future. I have ran a non-synchro trans in an old ******, and an older Ford, so that part doesn't scare me to much. I'm just looking for input on "friendliness" of the different boxes, as this is supposed to be a fun truck.

Russ Roth

Well, this is just my opinion so take it for what its worth. The 18 speed will give you the greatest gear coverage so that's a plus. My brother used to drive one and I filled in a couple times for him. It was pretty nice. It eliminated the drop between low/high range on a 13 speed. Nine speed also since it is a 13 without the splitter. I didn't like the 9 speeds. I'm currently driving a 10 speed which works pretty well. The newer ones (since I don't know when, maybe '95) are pretty good. They have a low enough low gear and reverse which the older ones did not. Some guys like 13 speeds real well but I like the 10 speed better since it doesn't have an air shift splitter and the longer drop between ranges. My personal favorite, which I haven't seen for awhile, is a 15 speed. It's a 10 speed with a couple lower gears. Since I work for someone else, I drive what they give me.

wannadiesel

Well, if you define "friendly" as being effortless to drive in heavy traffic, none of them are friendly. You will soon understand why professional truck drivers drive the way that they do. Once you learn to drive them, they are easy to drive (no clutching needed once you get moving). It's actually a lot of fun once you get the hang of it, but you learn to hate traffic lights and stop signs because then you have to start again at the bottom. Which you will want to do since it's YOUR clutch.

The biggest thing to remember when driving any of these transmissions is that you can't hurry them. Don't be in a rush, take your time and be smooth.

It sounds to me like a 9 or 10 speed would suit you fine. You are running so light that you would always want to be skipping gears on an 18 speed anyway. Skipping gears is a more difficult skill than running through the gears in order.

1-5-3-6-2-4

yes none of them are "friendly" in traffic. but though not hard to drive like was said once you get the hang of it. wannadiesel said don't rush shifts, I suggest its impossible to rush a shift. because the tranny will not shift until the shafts match speeds. we all know the sound.

I'd suggest a 13 as well for you. if you're looking at a class 7/8 truck. if you look into a class 5/6 I like the 10s


these are what make the noise............no syncronizers on any gears.

Darryl&Rita

So Luke, are all those gear teeth for torque capacity, or is that one of those 100 speed RoadRanger? I figured an 18 would probably mean more shifting(never even thought about skip-shifting), and that it was probably WAY overkill for the weight I'm looking at. I made that guesstimate based on the torque curve for these big diesels being like a two-stroke dirt bike, just at a lot lower RPM.

1-5-3-6-2-4

that is a pic of a regular 18 eaton. the twin countershafts are for torque capacity yes. the mack triple shaft box is a Beast among monsters. but thats not what you need. They're all just a regular 5 speed forward box. using different range and splitter combinations in the housing piggybacked on the back of the main case you make the gear combinations. 13 15 18. the red splitter switch is a 13 speed. a blue splitter is a 15. grey switch is an 18.

13 would be a good choice but a 10 would do you good too. with no range box on the back of the main case on a 10, it makes the tranny considerably lighter. which you want to keep in mind "light weight" for better fuel economy too.

when I bobtail a tractor to roadtest it. depending on the horsepower rating. I usually make top gear (regardless if its a 13 or 18) in 4 shifts and 1 split on top gear. if its lower HP or an old bird, maybe 5 shifts and 1 split. then they usually runs 1400rpm-ish at 110km/h of course depending on rear ratios and tire height. but generally close to 1400-1500 at highway speed.

rich

super 10 sucks all the others are pretty easy. 18 is more pullin heavy weight

wannadiesel

Oh yes, we know it all too well!

Perhaps it's better to say - Don't hurry because the transmission will only frustrate you further.

What was it that guy from Car & Driver said about road testing the Harley Lonestar? Something like "the transmission hates you and wants you to fail?" It's funny because it's true.

1-5-3-6-2-4

Thats pure GOLD right there.

Darryl&Rita

Good info here guys. I'm guessing these are not lightweight trannys, so if a 10 speed is lots lighter, I may not exclude it as fast . I thought it was a flat ground, low torque, low HP special. I don't think that I need to go as far as 18 though, although that much Jake would be sweeeet.

RollOver Pete

A set of sticks is what I broke in on.
Spicer 6 X 4 is my combo of choice.

Hvytrkmech

Left arm through the steering wheel while shifting the primary.

Russ Roth

I drove for several years before I drove a single stick myself. An outfit I worked part time for used to put a new hire with me once in a while. First thing I would ask them if they ever drove two sticks. Without fail not a clue. At the company picnic a few years ago the old man had a new tractor and the old LT Mack he had brought over. It had a tri-plex and I ask my brother how many guys besides us do you think could drive this rig? We figured about 4 out of maybe 50-60.