My 1997 Toyota Prado (TZ) is a Japanese import. It has a 1-kz engine and automatic transmission. It is currently in full time 4WD with no button or way of making it 2WD. I would like to know how I can modify it so that I can change in and out of 4WD when needed as at present I do a lot of driving around on sealed roads and being 4WD it is no so good on fuel economy and tyres. I note a lot of the Toyota Surfs (around 1996 and 1997) have 4WD selection buttons on the transfer lever, whereas my Prado does not. Can you please outline how I can modify my vehicle so that I can change between 4WD and 2WD. I think the 1997 Surfs and Prado vehicles have the same engine and transmission so in theory it should not be to hard to make similar??? I think I will also need to change the front hubs to a manual locking system as at present they are locked full time.Any help will be much appreciated. Cheers
Country: New ZealandMake: ToyotaModel: Prado TZYear: 1997Engine: 1 KZ
Thank you for choosing Just Answers. My Name is Mark.
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There should be a stubby lever on the left side of your transmission tunnel that engages and locks the Center Diff. If this is in normal 4WD HI, then the transmission Diff ( Center Diff) will be unlocked and you will be in 2wd so to speak. Yes drive can be transmitted to both front and rear, but if the center diff is not locked then there will be no axle wind up on sealed roads. The center diff will work the same as any normal diff in that the drive will be directed to the wheels with the least amount of traction. To test this you can jack up one wheel just off the ground and your car will not drive forward unless the lever is in the locked position. if you put manually locking hubs in your car and unlock them then you will not be able to drive without being in the 4wd locked position. This is just the way these cars are designed. Having said that, if you fit the manual hubs and drive the car in the 4wd locked position then you will not be turning ( driving) the front wheels. This will allow you to select 4wd and 2 wd, but only if you engage the hubs. The lever must always be in the locked 4wd position. I know this is not what you wanted to hear, but if you need clarification on anything I have said above, then please get back to me. I will be only too happy to help or clear up any doubtful points. Cheers Mark
Thanks MarkIdeally I would like to have a system that would enable me to have only 2WD rather than full time AWD. I have been reading a few 4WD forums and some people advise against using the High Lock if the font hubs are disengaged. I'm not sure why. I guess the drive shaft and diff will be spinning with no power reaching the front wheels.I have heard that I will need to find a late model surf transfer case, as they are the same dimensions but with a solinoid or vacume system that will disengage drive to the font diff. How diffucuilt is it to remove the Transfer Case and replace it with a Surf Case? Also is it relatviely easy to change the hubs over from the current ones to a a set of manual hubs? Is is a matter of just removing the current set and bolting on the Manual hubs or are modifications required?CheersMarcus
Marcus, should be able to buy off the shelf items for the manual hubs, but I still cant understand why you would want to do this. It will mean that you will have to get out of your car to engage them instead of engaging your center diff on the fly. If your concern is the amount of fuel that you are using, then the cost of a new T-case and an adapter set to fit it up, plus the switching set up ( Electrically operated on the one you suggest) would cost a small fortune.. more than what you could expect to save on fuel and tyres. If your tyres are wearing badly then have your alignment checked both front and rear. I have found that this is the major cause of tyre wear as most people dont want to spent the few extra dollars for a front and rear alignment. If however, your tyres are chirping as you go around corners then your center diff is locking up for some reason when its should be unlocked. This would have to be investigated as you would be experiencing very severe axle wind up. To check this drive around the block on one direction only then park the car and jack up one wheel. If the wheel starts to spin ( a fair bit) as soon as it leaves the ground then you have axle wind up.
What your reading in the Forums about driving with the front hubs unlocked and the T-case locked being bad is definitely not true. It is better for the front propshaft to spin otherwise it just sits in one spot and bounces up and down causing premature wear in the shaft spline. Same goes for the crownwheel and pinion. This is one of the reasons that most 4wds are constant 4wd these days, as its much kinder on the drive line. What you want to do is certainly possible, but at what cost. I would expect that even if you could get an adapter kit to bolt up a different T-case you would be up for a couple of thousand $$, plus the cost of the freewheeling manual hubs and the electrical switching system to engage and disengage the T-case. Thats a lot of fuel.... especially when your only talking about the difference of a few cents per KM. not to mention that there is no guarantee that you will save any money at all.
Sorry mate, I know this is not what you wanted to hear, but I think I should be frank about it. Unless you have a specific reason to change over ( eg competition use) then I would strongly recommend that you dont. At least on a cost basis. IF however you still want to go ahead with it, then try speaking to a company called Marks Adapters and see what they think. They are the best in the business, and have done some awesome and wild conversions. Good luck, and keep the shinny side up.Cheers Mark
26 Years as a Vehicle Mechanic in Australian Military