What make\model trucks have single 40k rear end?

23,000 is about as high as you'll get on a single screw axle rating. Most tandem drive setups are rated for 40,000.

 

I think the Meritor RS-160 is about the beefiest axle out there.
only rated at 25000 pounds

 

You would probably get a 2-axle sleeper to scale legally with a 34,000 lb trailer. That trailer you're pulling probably has fixed tandems I'm guessing so that could be an issue but I'm guessing that trailer was probably designed to be pulled by a single screw tractor and will just barely scale correctly. I figured a 2 axle sleeper pulling a dry van could probably scale up to 30,000 lbs load if it was loaded right and the axles were slid all the way forward, and then of course the trailer itself weighs ~15,000 lbs so you're nowhere near that.

 

Axle ratings (like 38k, 40k, 44k, 46k, 69k etc) are the ratings for the entire axle group, not the individual axles themselves.

 

Exacly.
So a tandem configuration rated at 40,000 lb is two 20,000 axles.
46,0000 is two 23,000 axles
69,000 is three 23,000 axles

Get the idea.

There is no such thing as a 40,000 single axle hwy tractor.

23,000 is about as big as they get in a on hwy app

 

I got curious and looked at Meritor's catalog...they do make single drive axles in 25,000, 26,000 and 30,000 lb ratings as well but IDK what the practical application would be, at least in the US where you're limited to 20,000 anyway. Maybe in Canada they can get away with such shenanigans.

https://www.meritor.com/productsandservices/truckproducts/pdfs/MeritorAxles_HeavyDutyVocational.pdf

 

So let me get this straight, your trailer is 34k gvwr and it is never going to change?

So you are going to put that entire trailer onto the back of the truck so you need to have over 40k axle on the truck to take all the weight, right?

I think some missed the point that the weight of the trailer should be balanced and with a single axle or double axle, the weight on the truck shouldn't approach the weight limit of the truck axle but it won't be anything near 34k because the trailer has two axles already ... right?

or did I miss something?

 

Except that you're not.