New Truck, 8LL Trans

In my minimal experience, the manual is correct...

 

No low gear low split in an 18 speed is not lower than Lo Lo in a 8LL. The 18 speed has a 14.40 to 1 low gear and the 8LL has a 14.56 to 1 low hole. From the drivers seat you cant feel the differance. Thats less then 1 % but the 18 speed is actually slightly higher.
As far as a need for the 8LL its more "dummy proof" than an 18. Through a rookie in with an 18 and they will tear it up. An 8LL shifts like a 9 speed so its less likely to get a driver that cant handle it. A lot of companies dont have time to train a driver to use an 18. As far as going 75 the rears determin how fast the truck will go. High gear in a 8LL is the same as an 18 speed. An 8LL would be like driving an 18 without a splitter. The 8LL is a great trans for a dump truck. I had one in a tractor with a 500 Detroit grossing 107,000 every load and it worked fine. Do I like my 18 speed I have now better? Yes, But an 8LL will do the job just fine. Off road they work just as good as an 18 getting a load rolling and they are better than a 9, 10 or 13 as far as low gear goes.
As far as the blue button goes think of it like 4 LOW in a 4x4. Most of the time you dont need it but if your real heavy on a steep grade, or on real soft ground it will get you rolling with out abuseing the truck. Its also good for slow going in tight spaces.

 

i normally put mine in lowlow and shift until i get to the last hole on the low side, then i put it in nuetral, flip the side splitter, then put it back in the big hole on the low side, and then resume shifting normal.( i hope i explained this clearly)


btw, i have an 8LL in a dump truck and i can do 87 mph grossing 70,000 if i really feel the need.

we also have 1 that will do triple digits with an 8LL

 

if i remember right my 8ll had a lot taller high gear than my 13 did. my ole w9 would easily run triple digits. really more of a matter of the rear ratio.loved the low reverse, no clutching when backing up. you could walk faster than it would back up and the same for low 1 going forward.

 

James pretty much nailed how most people drive their 8LL's. You could preselect and shift it like an 13 if you were careful but it was safer to pull it into neutral and back into the same gear. I found that mine shifted faster than my 18 spd. Meaning on steep hills or soft ground ther was less chance of coming to a stop with 130,000 lbs. Mine was a reverse pattern OD and it had big rpm drops (500 rpm) It would work that motor (425 CAT)over in the top two gears. But it was a fast OD. With 4.11 gears and small rubber it would cruise 70 mph # 1750 rpm. Never had to downshift for small rolling hills LOL. BTW a 15 spd is a close cousin of the 8LL so all the same rules apply.

 

i forgot about the 15 but you are rite, basically just one extra hole.

 

I drove a CL713 mack triaxle dump for a couple years till I got this W9. The Mack had an 8LL If you know how to drive you will never tear up this tranny. It's about the only thing I liked about that Mack. I'm not sure what a manuel would say. But I used the deep reduction all the time in all the gears on the lower side of the tranny. I don't think it hurts it but someone could probally tell you better then I can. This just worked for me.

 

we have 8LL in our dumptrucks and they work nice when off road because you get that deep reduction and they do just fine on the highway

 

16908LL
GEAR RATIO % STEP RATIO % STEP​

8th 1.00 .74
7th 1.34 1.00
6th 1.83 1.36
5th 2.46 1.83
Range Shift
4th 3.40 2.53
3rd 4.58 3.40
2nd 6.23 4.63
1st 8.39 6.24
Low 12.67 9.42
Lo-Lo 19.58 14.56
Hi Reverse 3.89 2.89
Low Reverse 13.24 9.95
Lo-Lo Reverse 20.47 15.22
Overall 19.58 19.58​

Ratios and Steps:


A 13 ir 18 speed has a top gear ratio of .73, the 8 speed is .74 so not much difference. ​

 

Thanks for all your comments
Seems like everyone drive it their way, but when I think about it, is it really useful to shift other gears (than LL) when you are in deep reduction as you may loose some speed while moving the shift lever.
Whereas when you stay in the LOW gear position you only have to "button shift"
??