full time to part time

Nothing wrong with it and if your circumstances suit then leave it....

If you wish to rid yourself of parasitic horsepower and save fuel and wear and tear on a front axle assembly then go for it.

It a personal thing..each to their own.

Matt Mu

What saving on fuel?

Thanks in advance.

EV700

EV700

The whole front axle????

Cheers!

Hi Matt,

I'd have to say I find the "parasitic horsepower/fuel savings" argument less than convincing. Perhaps in the days of the PT4WD days and "to free-wheel hub or not to FWH?" it had some significance.

In conventional PT system, the engine drive the vehicle via the rear axle, then the vehicle, via the front wheels 'drives' the front axles, diff and prop-shaft, to no good effect and using a small amount of power. Fitting FWH removes the front axles, diff and prop-shaft from the equation, potentially saving a small amount of fuel over a long period.

This is a bit different to a FT system where the engine drives both front and rear axles. And the front drive train is not being driven 'to no good effect' but is able to contribute to vehicle traction at any time, particularly on a wet or loose surface.

As for "less wear & tear", are the front drive components so weak and inferior that they can't be expected to last just as long as the rear ones? I don't see much point in retiring a generally worn-out vehicle with a relatively pristine front drive system... And this doesn't take into account the many PT front drive systems that have failed over the years because FW hubs had been disengaged for years. When finally required one day, the front drive failed because the unis had seized or the splines worn unevenly because of sitting in the one position for years on end.

Back to the Toyota FT system: is it a basic, driver-operated centre diff lock? Or some complex torque-biasing viscous coupling. Does it fail regularly? Matt, you said "if your circumstances suit then leave it" - when would it not suit to the extent of needing to spend $hundreds/thousands(?) to degrade it back to an old-fashioned PT system?

Bugga. Wish there was an "edit" function. second line shoudl read "PT4WD systems" Ian

OK Ian last response.....

First...dont think for a minute you are referring to the 80 series as a complex computer controlled, proportioning centre diff. This is a simple 'third' diff...where the path of least resistance (most likely wheel to spin) will spin.

If it was a WRX, CRV, etc AWD then the computer senses wheel spin (through ABS wheels speed sensors) that the front or rear wheels are losing traction and can send more torque to the wheels with grip. The eighty WONT the wheel that can spin will spin and all your drive will go out the front or rear axle, UNTILL you lock the centre difflock hence why you NEED to have that option! So no real advantage of this sytem with traction over a PT 4wd if there is perfect grip (dry bitumen) then yes you do share the load but we (as 4WDers) are concerned when there is less grip...so no advantage or little.

OK so with this rather crude AWD if you were taking off from the side of a road and give it a little too much then you could be spinning ONE wheel in the gravel. The will still move forward due to resistance of the gravel but the first wheel to hit the bitumen is the the drivers front wheel and the CV ( being the weakest link in the system). That is a HUGE shock load and one it doesnt need to be subjected to they cop enough abuse in 4WD without conventional driving wearing them out too. Look at any 4WD competition at what breaks first on a landcruiser. Most 80s had a read LSD so in 2wd the rear axle will be sharing the load beween L&R even if wheel sare spinning...the LSD will proportion the load and there isnt the shock when one wheel gets more traction than the other, the clutch packs absorb the traction gain.

So onto the next comment...is the front SOOOOOO weak that it shouldnt be used?? Well no it isnt sooo weak but it is the weakest...so why would you subject the weeakest diff(front) and the weakest axles (front and CVs) to more wear and tear than they need to be.

Lastly the fuel consumption.....if you dont have to turn the entire front diff assembly then you will use less fuel...same argument as the old FWH to no FWH..the part time kit for cruisers includes fitting FWH or you are not saving anything.

Now if you were in an alpine or heavy rain area and you need the extra traction on bitumen when you cant lock a centre difflock, then there is a great need for good AWD technology. But the cruiser isnt good AWD technology it was a little early for that. Now if the centre diff was an LSD or viscous or electro then the advantages would be huge...but then I would question the reliability in extream conditions which is what the cruiser was designed for...go hard or get and AWD!!!!

Ian I spent 15 years repairing LR 110s and have replaced more centre diffs, front CVs, front axles, front diffs, front diff pinions and tranfercase front output shafts than I can poke a stick at....can only count the rear axle repairs on one hand.

Matt.

ps for anyone who thinks this is a LC 80 series bash read carefully and then dont comment I think they are the best LC ever built. This reply was to Ians mislead comments about the AWD ststem. Cheers.

Im lost now! i was recommended by diesel and toyota experts to think about taking the constant 4wd system off to gain better fuel economy and reduce my overheating probs. Now can anyone tell me that has done this if it or was worth it??
Crawf
Cheers for all the replies though!!!

Ian, dont get too upset mate!

No-one is saying you have to do it, and no-one is saying you don't know what your talking about if you don't understand why someone else wants to do it to their vehicle!

Let him do what he wants with his money and his vehicle!

The main reason people with 80s and 100s cruisers want to do this is because these vehicles sometimes suffer from "driveline backlash" which is an annoying clunk clunk when changing gears.

An added benefit is better fuel economy. It also helps in the case of needing to use low range to back a heavy caravan up a steep driveway which can now be done whilst in 2WD.

Hi All,

I seem to have aroused a bit of emotion here. But I'm just trying to understand the reasoning behind these expensive PT conversions.

Matt, sorry if I gave you the wrong impression - I never suggested the 80 series had a "complex computer controlled, proportioning centre diff". I asked whether it had a "complex torque-biasing viscous coupling". That is, I was thinking a mechanical system similar to the late '80s Range Rover Borg-Warner transfer case. I didn't know what the Toyota system was, that's why I asked. So, it seems they have a simple centre differential. Thank you.

Also, by all means quote my words and refute them with facts but please don't attribute words to me that I haven't used. I did not say "is the front SOOOOOO weak that it shouldnt be used??", I asked "are the front drive components so weak and inferior that they can't be expected to last just as long as the rear ones?". Quite a different question and emphasis.

I can't dispute your account of your 15 years experience with LR 110 front drive components. I'm not a mechanic or vehicle repairer, so I have no first-hand experience. But I have been a regular on a number of Land Rover web forums since 2000 and front drive component failures is definitely NOT a common topic on them.

Thanks also for your analysis of different 4WD and AWD systems but I'm afraid none of that answers my original question: why change the original 80 series FT system to PT. Any fuel saving would be very small and would probably never repay the cost of the conversion for most users (please feel free to refute this with factual evidence if you can). So, presumably there is some other significant advantage to be gained. Please, tell me what it is?

Lastly Matt, you accuse me of misleading people ("This reply was to Ians mislead comments about the AWD ststem.") I'd appreciate a retraction of this. I have no intention to mislead anyone and, if you read my messages, you will find they consist largely of questions - reasonable questions in my opinion.

Muzzgit, I'm not the one getting upset about this. And, for sure, people can spend their money however they wish. I'm simply try to find out what the problem is and how a PT conversion solves it. Do people doing this actual gain anything for the money they spend? Your answer of excessive "driveline backlash" is the only one so far that makes sense to me. But surely a backlash problem could be repaired/rectified with going to the extent of a PT conversion?

I'm obviously not the only one confused by this issue. Fishaholic's message is very relevant. "experts" are telling him a PT conversion will "gain better fuel economy and reduce my overheating probs.." Fair go! As said, I'm not convinced that any fuel saving would ever pay for the costs. And as for "reduce my overheating probs" - must be one hell of a power-hungry front diff! I think he needs to consult some better "experts" about any overheating problem.

Just like Matt, I'm not out to "bash" the LC80. I also happen to regard them as the best LC wagon of the lot. I'm just questioning the worth of an expensive modification, the justification for which seems to be largely based on urban myth.

Fascinating discussion. Lets keep the FACTS coming.

Ian glad I could assist, but it sounds like I wasted all my time explaining the error of your original post relating to the benefits of the AWD system....

From the following post it seems you have wasted the last half an hour of your time trying to promote your intelligence rather than accept your comments on this subject were misleading or misguided...take your pick. The poster wanted information on the PT system not superfluous information that would just confuse him.

Im sorry I replied to your original response...I see it for the Troll that it was.

All the best.

Matt.

Oh and by the way...I dont feel the need to cut and paste others quotes into threads....I feel I am quite capable of paraphrasing a response.

"I dont feel the need to cut and paste others quotes into threads....I feel I am quite capable of paraphrasing a response." Yes, much easier that way to alter the meaning of someone else's words to suit your argument. But we'll let the readers judge this one.

"accept your comments on this subject were misleading or misguided" - please provide a direct quote (not a paraphrasing, please) on any statement I've made on this thread that is factually incorrect and I will immediately apologise.

Any new facts? So far it seems that: The Toyota 80 series FT 4WD system should be changed to PT because it MIGHT break if you take-off from gravel onto bitumen in a ham-fisted manner. Is that the full extent of the argument?

Troll? No, genuine question. I admit this PT conversion business has always had the sniff of 'snake oil' to me. And the level of emotive response and lack of solid, measurable and worthwhile benefits does little to alter this opinion.

"The poster wanted information on the PT system not superfluous information that would just confuse him." I think you underestimate the ability of Fishoholic to follow reasoned argument. So having the hide to ask, "what does it actually achieve" is superfluous information, is it?

Why does it appear to be such a crime to question the worth of this modification? Perhaps the Emperor is getting around in his jocks?

A quick one to Muzzgit,

You say, "It also helps in the case of needing to use low range to back a heavy caravan up a steep driveway which can now be done whilst in 2WD." Can't you engage low range without also engaging the centre diff lock in the Toyota FT system? If so, that would be a nuisance.

Ian,

No, the centre diff lock engages automatically on selecting low range. There is a work around posted on the LCOOL site though if needed.

Matt.

Yep, you are right. The cost of conversion would never be realised in fuel savings, but a lot of 80 owners (myself included) have it done as part of other repairs that needed doing. It does save fuel, but as you point out it would be difficult to quantify. I have found that the steering is lighter since I have had it done but the main advantage is in eliminating any backlash from the front drive train for day to day use. A good solution to get rid of an annoying problem in an otherwise serviceable drive train.

You point out that there is not much real data on this thread but then discuss the difference in fuel consumption between your two vehicles. Are we supposed to believe that the difference in fuel consumption between two different vehicles with different engines is because one is full time 4WD and one part time? Seems like very rubbery data.

Cheers,

Matt.

I wasn't trying to claim that my 110 uses less fuel because of constant 4x4 - just that pushing 2tonnes of 4x4 around takes about the same amount of energy(fuel), no matter how many axles you are turning.

I find it strange that people are willing to give up ABS to have this mod. Which makes the mod illegal AFAIK??? I think most states (or even the ADRs) have a rule about not making any modifications which have an adverse effect on safety...