on the way over tuesday night I got stuck in the shell truck stop parking lot in West Burlington. took me 3hrs but I managed to get myself out of there. During the height of that storm I took an hour to drive 6 miles staring out the drivers side window ot see the side of the roadway. had 3 cars behind me using me as a guide until i finally got to the exit where I could safely get off the road.

 

Man you guys are killing me. I have got to get a four wheel drive!

 

four wheel drive?

try semi tractor trailer.

 

But Rob, how many of the drives can you lock together on yours?

 

I know it's crappy cell phone pic but here is the truck that got stuck and caused the whole thing yesterday. You can at least get the idea of how much snow.

 

Just 2 (open diffs but I can lock the diffs together)

oh and I have "super singles"

Not my truck but these are the tires I am running

 

O that sucks, too bad you dont have the axle lock too, makes a huge difference sometimes...

 

OTR trucks rarely have the axle locks. Way to dang expensive on that type of axle and companies are always trying to get the trucks cheap as possible.

 

Hey Rob! My dad is a trucker! I have a lot of respect for truckers. I know the kind of junk they have to put up with and the skill they have.

Can you please explain to me how exactly the differentials work in a semi? I know you can lock yours up, but you said you have open diffs?

Does this mean you can make both axles transmit power to the tire? Or does this mean you can lock up both tires on both axles?

PLEASE explain!

And how does the gear ratios work in a semi? The numbers are the same right?

 

yeah, that pic looks about right. my back is sore as hell today from all the shoveling, but you gotta do what you gotta do. it was drifted half up my garage door and a solid 4 foot high across the whole front of the house. i'm sure it would have been more, but it stopped snowing after a while and the wind drifted some elsewhere away from the house.

p.s. it's nice to be able to use my front door again, the garage almost didn't want to open either. lucky for us we have a glass slider for the back patio, but even that side of the house had 2 foot drifted all across my patio

 

the lock he's reffering to is not a differential lock like you are thinking bill. they do have that kind though, robs truck just doesn't have any in the drive axles. he'll give a better explanation but the lock he talked about is for making the tandem axles get equal drive power from the tranny iirc.

 

Simple question first. yes gear ratios are the same numbers. Like my truck has 3.31:1 gear ratio. with the talll tires and the over drive trans it is why I can run 70mph at 1450rpm.

As to the diffs. each axle is just like a car differential without any type of locker or posi unit I.E. an open diff. but there is a power divider inside of one of the diffs that puts power THRU the front differential into a jackshaft to drive the rear diff. What it means when I lock it, there is the equivalent to an air locker in there that locks that power divider solid kind of like a t-case I guess is the best description. In open mode it works like an all wheel drive tcase, which puts power to which ever set has the least traction. Lock it and it's solid both diffs will get the same power. So when your unlocked you can spin 1 out of 4 tires, when locked you WILL spin atleast 2... one from each differential "usually opposite sides but not necessarily)

Eaton does make an air locker for these axles but they are VERY expensive (last I heard around $2500-3000 each JUST for the locker) usually only SA trucks and things like oil field trucks are the only ones that get those.

 

I'd say half the owner operators I know have diff locks, the other half not.. In fact my Dads pete doesnt have diff locks, I've had to use my wheeler to drag his tractor up a slight icy incline because of how ****ty they do without a load..

 

If they spec their own trucks and run up north then yes. I haven't owned my own truck in 12yrs tho and when I did I bought used as I couldn't afford the hit for a new truck. Last one I bought was a 95 T600 KW with a at the time 430 series 60 which I turned to a 470hp. It was an ex JTI company truck with a 10sp OD.

 

Yep, thats how it is too, the guys that bought new, and ordered them how they wanted, so they got the locks.. Dads rig was used when he got it, so it didnt have any locks....

and the way things are going now, keeping what he has is what he is going to do untell the gobernment tells him he needs a DPF on it to run in cali, than he said he might just not go out there anymore...