Advantages & disadvantages of Auto off road

[Paul Woodward]

Previously I would have never wanted an Auto road car, now days I can't see the point of not having one.

Me too. I've been told it's because I'm getting old!

I got stuck once on a wet grassy bank that you could barely stand up on. A guy in a auto Range Rover reversed down, hooked on his rope and pulled me up. It was easy, so controlled with no wheel spin. We were on the same make and size of tyre too. I think I'd go for a viscous transfer box as well if you could get them in the 1.4 ratio.

[heath robinson]

I have read that on road in a TDI Auto is not a joy to behold, considering I use my 90 for tasks other than pure off road ventures, I would have to consider this

Having had mine for a few years, I have to agree. I used the selector (You can't really class it as a proper gearstick, can you) as much as possible, but it's not half as much fun as the manual in the CSW. However, towing heavy vans out of muddy fields, and carting heavy stuff about over marshy bits, it's invaluable. As paul said, makes things like that easy. I just wish that there was a similar device to what Will mentioned, that let me dictate it's actions.

[ashtrans]

I'm not sure you can get if for a ZF4 autobox - they are the stuff of racers/drag cars normally. You could try Ashcrofts as your first port of call. The thing is I'm not exactly using a gearbox from a Land Rover and it isn't terribly standard - it is rated to 900 bhp.....

if you put the compushift on a ZF you have the best of both worlds :

normal auto,

Tiptronic auto, with either paddle shifters or a spring loaded 'sequential' lever,

full manual control,

Dave

[heath robinson]

But you need a 'leccy autobox in the first place, don't you? One day, when I'm rich and famous...

The effect that I'd like to achieve is as if there were no kickdown, so the box changes up at the earliest opportunity, unless held down with the selector. However, without the kickdown, the thing would lock the converter in top asap, irrespective of throttle, which would be a bit pants. Effectively, i'd like the choice of 1, 2, 3, 4, and Lock. I know that compushift solves this, and a whole lot more besides, I just wish that there was a bodge until I've sold enough of my soul to afford it

[will_warne]

... But how many lb/ft? The shaft in a turbocharger is delivering c.80 horsepower and they're quite spindly...

A pleasingly symetrical 900 lb/ft

Heath Robinson, the gearbox I've got is no cheap option - compushift and a rebuilt electronic 'box would cost considerably less...

[plasticbadger]

Manual valve bodies for the more common Yank boxes are pretty cheap ranging from simple manual/automatic valve bodies for the TH350 at about $150 upto offroad specific full manual valve bodies for the 700R4 for $400.

For those new to these things, older non-electronic autos can have the valve body modified or replaced to do anything from holding a gear to higher revs, lock up earlier, or only change manually. Most manufacturers offer Auto/Manual kits where you can manually select and hold any gear, plus have the original fully automatic function, then a full manual kit where you can only manually change gear, and then various reverse shift pattern or increased engine braking options (for 4x4s).

Ok, so it's not standard Landrover stuff, but you can get kits to mount a Rover V8 onto a TH400 and kits to mount an LT230 to TH400, so you could just swap the box out....

Just one thought, what's the early RRC 3 speed box, a Torqueflite? You can get a full manual valve body for the Torqueflite 727

[heath robinson]

To be honest, I can see how the effect could be achieved if you could get the torque converter to lock by choice.

I think, from what I've read, that this is quite a tricky proposition. The actual workings of the valve pack without the kickdown cable, or the converter locking up at 54 in top are pretty much as I'd want them. Before I'd bodged crafted the kickdown adapter for my carb-fed engine, I drove for a month or two. Up to the point that it locked up, if you used the selector it was fine. It was only when you hit 54 that there was a problem. If I've got this right, it is the flow of fluid from the governor that dictates this bit. Not a lot to be done about it really, except look into the TH350/400.

Probably a cheaper pipe-dream than the Compushift, but still out of reach for the moment. Hey ho. There's a small chance that I might get my mitts on a ZF box with knackered splines, which I might give to my friendly local genius mechanic and tinkerer. If he can make a tiny jet engine out of an old turbo in a few hours, maybe he can wrestle the 'box into shape.

Much food for though for my tiny mind to contemplate, while my hands get my truck working again.

[Lara]

I have a little button on the dash that locks the TC in an instant!!

Has a pre-set minimum speed threshold to unlock before engine stall, which is about 1kmh in low range and 10 in high! works great although the need is minimal as it locks itself as soon as you lift completely from the throttle anyway!

Lara.

I like the reliability of a good Auto!

And if you are not scared of it, you "Could" field repair one in emergency to get you halfway round the world! "if you needed to"

[M005]

After a jaunt across the Plain on Friday (it was the most direct route home from picking up the new LR - honest ) I can confirm that I found the auto great offroad.

Although I did feel that it added an additional element to the armchair offroading that the Disco gives, no leather though so still not the dizzy heights of BishBosh & Bishtail

[heath robinson]

Lara, from whence came yer little button? I now seem to be the mildly baffled owner of a 24e.

[lrfarmer]

have thought about putting the series diffs back in to the rangerover axles i put on which would lower my gearing and give me the control back. but with the series gearbox i dont have much options for ratio changes so then end up with poor cruising gearing again.

a well set up manual and decent strength drivetrain is good (and the boxes are so simple that they cant really go wrong unless they're not strong enough) combined with a decent driver, but without using clutch you're never going to be able to get the slow crawl that you can get with an auto which i can see being a big bonus to me doing rtv trials.

i think the decision comes down to what sort of offroading you're doing

from my experance autos are good off road but for doing the RTV's i like my manual gear box.

[kourgath]

Hiya (sorry for bringing an older thread back),

I converted my 90 from manual to auto about 10 years ago. I RTV and had got to 3rd overall in the club at them in my manual 88 coiler special. Last year I made 7th and 3 class wins in the larger (in every direction) auto 90. I teach 4x4 driving and have plenty of experience driving both manual and auto. [Just setting out my experience]

I love the auto, I feel more in control of forward speed than in a manual - OK so it's got a lightly tuned 4.6 in front of it and this possibly makes a difference

I can left-foot brake giving me power-braking on steep slopes if I want, I can tickle it gently when close to an tree and I only broke one when following advice to "rock between D and R" to get out of a hole - OK with the BW 65 or 727 boxes - don't do this on a ZF - overdrive cluster gets smashed - reconditioning required.

I put in a BW viscous transfer box which had slightly high gearing and had to put in 4.1 diffs to bring it back to sensible (it would do over 60mph in 2nd). Let's be honest a good 2/300 TDi Disco on normal sized tyres has awesome engine braking, in a direct comparison it is way slower than my 90 (and a TD5 90). However, a std TD5 90 and mine are not so different with the TD5 being a little slower. I have not tried a new TD4 but apparently LR remapped it in low 1st to 3.4mph min so as not to destroy the new 6spd manual... now 3.4mph is a fast walking pace... so not so different.

My auto 90 is about the same speed down steep (35deg) hills as most other non LR 4x4s (having tried lots of them on the same hill at our site). It does pick up a bit of speed on very long descents but nothing too fast. Unlike a F*rd Ranger we had in with 24k on the clock - now that was scary - almost no engine braking at all

Some of our clients love the auto some don't. Personal preference - you have to _drive_ the auto off-road whereas the tdi/td5/td4 push along without your input at slow revs.

Have fun whatever you use!

Cheers

kourgath

[GARY ANDREWS]

to make an auto complete put a underdrive on it, you crawl down hill and have your wheels turn at winch speed