Engines for 18 Speed Eaton

If the price is right and you feel up to the challenge go for it, but like said in prior replies....it won't be "plug and play" the last 18spd I had was in a 97 pete 379 with a 550 cat, the bottom gears where just xtras that never got used.

Jim

 

Adding the clutch pedal and shift mechanism will have him scratching his head more than the rest of it.

18 speeds are typically rated for higher torque than what a C10 or a C12 puts out. I'd make sure you can correctly mate the input shaft of the tranny to a clutch that will go with the flywheel size.

 

You should check out a Eaton ratio chart because they aren't the same transmission. The 18 has a much lower gear ratio in low and reverse than the 13.

 

If that 18 don't work out for you let me know the serial number on it and I'll pick it up from you. If it doesn't work for you but dont butcher it.

 

I like the 18, but tied to a 2.79, or even a 2.65, rear end for general freight highway work. I use it in 16th (direct drive) most of the time for maximum efficiency. If I feel the need to step up the pace a little, then go to 17th. Most would think this is wasteful of an 18. But just like we all don't go thru each and every gear with a lower rear end and overdrive, there is no need to use the top holes all the time, and it can work quite well with taller rears. As was stated by OLDSKOOLERnWV, most 18 hardly ever get all the lower gears used. But that is with the typical 3.55 or such rear end. I do the reverse. I run taller rears and never use the top hole, and barely ever use 17th. 1400 RPM in 16th and 2.79 rears with low pro rubber is 58 mph. 1600 RPM is 67 mph. Great range / speed combo for what I normally do and where i run. If I am on the flat ground, light load, and no high winds, then 1400 in 17th sets me on 68 mph, with 1500 at 73 mph. I can step up the pace if I feel the need and still keep RPM's in a good range for my engine. Meanwhile, for most of the rolling hill, heavy load stuff I do, the 16th (direct) gives me the maximum power to the rears for that application within the speed limits of those areas. It is just as important to tie the 18 (or any other tranny) to the right rear end ratio for the application.

The 18 is very versatile for a broad range of applications. More so than the 13, which I also like. It isn't just for the macho or heavy haul crowd. Set up with the right engine and rear end ratios, it can be a great performer and very fuel efficient combo. Of course, it also means the driver must be more than a steering wheel holder.

 

A 13 speed normally has 500 RPM between shifts an 18 has 300 RPM. An 18 behind a C10 is a lot of overkill.
You do not want an auto shift transmission with a Cat they are away to slow to shift.

 

Sorry John but this statement is SO WRONG!. While the 18 may be more than necessary strength wise for a little motor, having 18 speeds is EXACTLY what one would need if they are a bit short on power. It's the very reason that 18's are used in heavy haul...power to weight ratio. If you lower the power to weight ratio either by increasing the weight or reducing the power, you need more gears geared closer together. Conversely, if you have 800HP and are running bobtail, you can get by with just hitting maybe 4 or 5 gears from stop to highway speed because you have a very high power to weight ratio.

 

Agree..... there is no such thing as an 18 being overkill. Even with a 10 speed and light load, one can skip gears. Sure you would skip more of them with an 18, but the versatility of an 18 is so much more. Is it needed in every application? Of course not. But it also is applicable to every application there is, unlike a 9, 10, or 13. If one is light, then just shift it like a 9. Got a little more weight? then shift it like a 13 (only on the top side where it is needed). Got a really nasty load? Then use more of the splits on the bottom if you need to. I am sure that there is someone that has had an 18 and didn't like the versatility of it, but those people are few and far between.

 

If your talking a Mack transmission then your right they are the same trans with a different shift knob. Their is a lock out that only lets the splitter be used in the high range position. With the Eaton fuller roadranger they are definitely NOT the same trans. The gear ratios on the low side of an 18 speed is much lower. 12.31:1 Low in a 13. 14.40 Low in an 18. Thats a lot lower.

 

No your WRONG. The splits are exactly the same.