18 speed

I have a 92 T800 that I pull a belly dump gravel trailer. It has 60 series, 18 spd, 4.33 rear ends. There is one gravel pit that when you pull on to the highway you have a quartermile steep pull up the hill. That is the only time I split the bottom so far. Pull on to the road in 2nd/over, shift to 3rd over, then split to 4th/direct, then 4th over, then finally go 5th direct. With the gearing it's moving so slow that timing is very critical to split the bottom on a hard pull with out tearing something up. 99% of the time I leave it in overdrive and drive like a 9spd.

 

not quite true 9LL has a 28:1 low hole 18spd is a good on road trans. but to do serious off road heavy hauling its going to need 2 spd rears or auxillary trans to get enough reduction

Mack 13 and 18spd have a 16:1 low hole and .71 od

 

pretty darn heavy.. all the log trucks around here are 18 speeds(usually 4.10 or 4.30 gears as well), and fully loaded(normally 180-200K), you still would only need to split 7th and 8th. However, for in the woods, or especially on big hills, where the every half gear counts, when your down in 2nd or 3rd gear..

 

Last I checked you could only get a mack tranny with a mack so for everything else the 18 spd roadranger has the lowest gearing for a high torque tranny. That 9LL is a 16909ALL LL= 26.08 L=16.30 with an 18 spd you can get a 22918 I don't think 98% of the trucks on the road would ever need anything lower than what you get with an 18 spd, I've had 110k sunk to my fuel tanks in soft dirt and pulled out of it and in 220k miles have never needed to adjust the clutch

 

18 all the way

 

I've had 110k sunk to my fuel tanks in soft dirt and pulled out of it and in 220k miles have never needed to adjust the clutch

Sounds like you got lucky, I've grossed around 130k off road and if your truck and trailer falls in 8" or so grabing lo lo and hitting the locks does not get you through its hard to push a front end thats fell to the axle and pull a load like that through mud

if you have enough reduction you should not be riding the clutch to get started so yeah clutch will hold drive shafts and axles are a diffrent story

 

Ummm, 19 axle, 6% grade starting out after a "well intentioned" cop had stopped you in the steepest part of the grade???? Allison 4560, 2.00 converter, AAT1202 in low, & 3.90, w/ 24.5 lopro's, still more than I liked to apply

 

so very true... I still have one of the shafts from my buddies old log truck on my porch, Sunk in about 8" in a soft hole in the road with about 27 cord of pulp on it. Power divider locked, diff locks in, all lift axles up for better traction(it puts about 75K on the drives when you do this for in the woods) Low gear in the 18 speed, let the clutch out at idle and it went "Bang" This was with 46K rears as well, 2 1/4" axle shafts, last I heard that truck was up 6 broken axles so far, although it wasn't exactly a stock 550 cat in it either... which didn't help
This is exactly why some of the trucks around here are going to tri-drives.

 

18 speed RTO trannies are nice.....

But you ain't a trucker until you driven a "twin-stick"....


http://www.youtube.com/watch?v=w-ffkS37miQ

 

Oh man!!!! Forget a double stick for me !!!! Much credit to those that have driven them. I think my mental capacity is lacking too much to remember what gear I'd be in!!! LOL