Transmission revisited

Hmmm, I dunno but are you sure about them figures, you have the NO 435 as 2.00 - 1 in top ?

Dunno if thats right but thinking it maybe wrong

If you're looking to cruise at 100 kmh I would be thinking the the 4.8 diff and the NP 445 with the joey box in od

But I dunno


Paul

Mrs,
Yeah, misprint, should have read 1.00:1 as top gear, been corrected, thanks.

Swishy,
Have been stuck with two alternative main transmissions, as pointed out, without redesigning the whole wheel!
Both transmissions give rhe same 4th gear ( final drive) ratios.
Simply put, I'm in a position whilst I have the cabin off, the transmission is relatively easy to reef out.
Whatever ratio transmission I use, has to have the PTO fitted for the hydraulic hoist.
The only difference will be the spread of ratios available in the lower gears in the main box, both will have a ridiculously low ratio in Lo-lo in the auxilliary, probably never be used.
Which means that the auxilliary then has only 3 usually available ratios, u'd-direct-o'd ,
Becomes a matter of which main trans is best suited with what I have.
Currently has the 5. Whatever ratio diff, but do have the lower ratio 4.8 if I want to use it.
Remembering this thing is only a hobby horse anyway, what I am going on is that the original engine came out of a Range Rover with an 0,82:1 overdrive manual trans with 17" wheels, bopping along around 2300 RPM at 100kph.
OK,my final drive ratio is going to be slightly higher, but maybe that will be offset by overall tyre size and diff ratios.
I dont have any problem in bopping along in either direct or overdrive at road speed, the exercise is simply which transmission is better suited to the same final drive ratios
Thats about as good as I can explain it
Dave

Cogz
gudday m8
Have U dun the figures run n with out a Auxilary box
OR
Turn the Auxilary Arse backwards

Just a thort

n U kno what Thort thought

LOL
cya

Correct me if I'm wrong, but the Kogsbilt is not going to be heavily loaded, most of the time, thus you will only need the main box until you get on the highway. It is my opinion (for what that's worth) that the 445 is going to be a lot more user friendly as a main box with its closer (yet still respectably wide) gear ratios, then pop into over when winding up on highway.
a 435 (and T98) require a lot of revs before changing up, I would think the 445 will be a lot nicer to use. It also has a helical, synchro first, yes? 435's have to be floated out of first unless you're crawling.
Unless I have misunderstood the whole thing...

Jarrod.

Re:- Reversing the aux??
Whole design and rebuild of the transmission was based on cost, mounting, best spread of ratios that I could achieve with what gearsets I had. Remote mounting cannot be reversed on top of gearbox, ratios would be PITA, even locking out Lo-Lo, which would be insanely overdriven!
Nah, stuck with it as is.
Had always intended running both a Main and an Auxulliary, whole idea of spending a Kings Ransom on it with all machining etc.

Both main trans can handle any amount of HP that I would ever want to chuck at it, the 445 came from behind a 440 cu in Mopar camper van, the 435 have seen and read galahs putting totally insane amounts of torque into them before they blew!
As stated earlier, both boxes take up exactly the same space, no shortening of jack shafts or main drive shafts, same bell housing etc, directly interchangeable, just a matter of deciding which main trans best suits the aux/diff ratio/ wheel size. Both boxes in Lo-Lo are really deep. would never use them.
445 in U/D yields around 6.5:1, 435 in U/D gives around 9.5:1 and as only going to be using U/D--Dir--O?D, whatever box I use, matter of which gives best spread of ratios. Given that BOTH boxes in 4th Direct, give 0.71:1 as final driven gear when aux in O/D, 100:1 in Dir-direct.
Its only 1st-2nd and 3rd in the main box that is an issue
Dave_64

Way way waaaaay back in the dim dark ages dinosaurs roamed the earth and trucks didn't have 600 hp gearing was pretty darn important

I reckon that there was a sweet spot were the lines for hp and torque crossed on the graph

So I reckon the ideal crusing speed was desired and they worked backwards to get diff ratios etc

I'm if you had those figures , hp and torque and your ideal cruising speed you can start to find a answer to your questions

You know the wheel size, the diff ratios available
The gear steps and the revs each gear change and so on,

I reckon with this information you could narrow it down pretty quick and see exactly which one is ideally suited


Paul

Agree with Mrsmackpaul and Jarrod.
445 more user friendly, all synchro and more evenly spaced ratios. Can split 2, 3 & 4 between direct and overdrive giving 7 useful forward gears, including 1 st.
If you haven’t already done so, have a look at You Tube on the Everlasting Towing Loadstar.
Expert operator with V6-53 & 5 x 3 trans.
Most interesting topic Dave. Good luck.

Sorry, Everlast Towing, Canberra.

Mrs,
It's obvious where I'm going wrong!
Had a cupla ex-wives who always reckoned that I was a dinosaur,
That and walked around with me head wedged somewhere unmentionable.
You try and work like that!
Dave

Dave, I stumbled across this Pic & thought of You for some reason....LOL