Failing gearboxes and the heavy matter of warped Hilux brakes

Baraza,

I own a 2006 2.5cc diesel Toyota Hilux double cabin pickup which has served me well for more than five years. However, of late I have noticed the following problems:

  1. If the car is parked in an uphill position, it takes time to move in the morning and I have to wait for it to warm up or accelerate slowly. This also happens during the day if the car is parked in an uphill position and stays for more than four or five hours without the engine being switched on. What could be the problem? What is the best transmission oil to use on the car, which I service on time always.
  2. I recently found out that my brake discs were bumpy and my mechanic advised me to skim them instead of buying new ones. However, after installing the skimmed discs and new brake pads, the braking feels bumpy. Is it advisable to skim the discs? Should I buy new discs before the new pads are spoilt?
  3. I would like to upgrade to a 2010 3.0 diesel Hilux Vigo. Will the consumption be significantly different since am going for a bigger engine now? 

Regards,

Fred Kariuki

 

Fred, you did not specify what transmission your Hilux has, but for the sake of argument, let’s go with the surmise that it is an automatic.

  1. This sounds like a low ATF (automatic transmission fluid) situation. When parked for a while, the ATF cools down, and from physics we know about the effect of heat on the volumes of substances — warming a substance causes it to expand. This explains why it takes some time before the vehicle reacts: the ATF is still warming up (and expanding) to the point where it reaches an acceptable level.

Parking the vehicle on a slope exacerbates the problem because the ATF tends to pool in one corner of the transmission sump, out of reach of the gear pump that sends transmission fluid between the torque converter and the gear set. It may therefore take some minutes before the pump builds up enough hydraulic pressure in the fluid to activate the clutches and bands that control the gears within the transmission.

This therefore means there are two or three things to check on: the fluid levels in the transmission, the integrity of the pump and if there is a blockage in the fluid channels.

The best transmission fluid to use is Toyota’s own. Toyota is one of the few manufacturers who actually have their own bespoke fluid — which may be similar to generic brands, but who knows? — and they will always insist on the users not going “rogue” on brands.

  1. Those discs are warped. Warped or cracked discs need replacement, because not many people have the equipment or know-how of re-machining the discs. Skimming the discs only sorts one type of problem — if the disc surfaces are scoured — but when it’s bent out of shape (what you call “bumpy”), skimming doesn’t help anything. It is like trying to clean or polish a dent after an accident. That doesn’t get rid of the dent, does it?

You are not the first to complain about the brake discs of a Hilux double cab. I have a friend who suffered a similar fate, though he blames his driver for overloading, reckless driving and riding the wheel brakes instead of using engine braking while going down the escarpment with that considerable load. The not-insubstantial heat generated from that must have warped the discs.

  1. There will be a difference in consumption, but not as much as you’d imagine. For starters (if you fix your transmission), the 3.0 will not take as much effort as the 2.5 to attain highway speeds, so there will be less revving. You might even get better economy figures as a result. I have driven both the 2.5 and the 3.0, and the 2.5 is the weak link in Toyota’s chain. That engine is woeful, to say the least; easily outgunned by rivals such as the Navara and Ford Ranger LT; both of which also have 2.5 liter turbodiesel mills.

 

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JM (Jose Mourinho?),

Kazi poa with your Wednesday pieces. I’ve noticed that you’ve touched on literally every part of the (normal) car — engine, transmission, tires — but shied away from the exterior. The paint job. And as you’ll agree, every vehicle owner (especially the new owners) love to clean their cars, and I’m wondering if one of these days you could do a piece on exterior care — paint jobs, buffing, waxing, polishing, washing — y’know, the pitfalls, advantages and so on. I know there’s not much to go on here, but you’re not one to run away from a challenge, you say. A few months ago I did full paintwork on my car and the technician said the new paint should serve me for the better part of three years. So far, so good, and I hope for both our sakes he’s right.

Dexter.

 

Dexter, no worries sir, I can touch on the exterior right here, right now. Keep your car clean, for starters. If you can afford it, have it waxed or polished at least once a month. When washing, avoid powerful detergents such as dishwashing fluids or laundry soap. These can easily bleach your paint and leave streaks, especially if the car is washed in strong sunlight (light rays from the sun, not the brand of soap). Also, avoid rough or coarse washcloths and instead go for sponges or cotton rags which are softer.

After a paint job, ask them if they have lacquer; and if they know how to apply it. If they don’t then they best leave it alone: a bad lacquer looks worse than no lacquer at all. Lacquer is like a vitamin: the right amount works wonders but too much of it becomes counterproductive.

The lacquer is what makes the car gleam, especially after buffing, and it acts as a trap for dust and small particles which might otherwise scour the paint. If your car is lacquered, again try not to park in direct sunlight if you can: the sun softens the lacquer and these dust particles can get embedded in it.

Speaking of scouring: there is the bane of every motorist who lives in a middle-class high-rise flat — children. Their parents will tell you children are blessings, but children are the agents of Beelzebub as far as paint jobs go. I’ve had children gnaw on my bumpers (those teeth marks were definitely human), conduct spelling bees on the doors using rusty nails and small rocks, and use the rear windscreen as a fingerprint analysis kit.

I’ve also had children break off my side mirrors and dislodge my door handles. One sunny afternoon in the presence of two or more bored children is enough for your car to be transformed from your pride and joy into a piece of abstract art. You might think you are the most patient man in the world until the time you walk up to your car to see stick figures of unknown four-legged animals stenciled neatly on your fenders. Then your screams of rage will be heard all the way in the next county.

Just like medication, paint jobs come with the warning “keep out of the reach of children”.

 

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Baraza,

When I hear of you, I already know my car is fixed. I own a Toyota Wish with an automatic gearbox. The reverse gear has failed, but all the forward gears are okay. Please give me a vaccine for the gearbox.

Thank you, Jesse Luvari

 

Jesse, this sounds like a solenoid assembly or intermediate clutch problem within the automatic transmission. Other less likely diagnoses would be problems with the torque converter (which has a one-way clutch/stator) that allows components to spin in one direction. If it fails, the car will have problems with reverse or the low gears. There is a possibility of a stripped gear set too. Check carefully under the bonnet: signs of metal filings or shavings mean the reverse gear set is stripped and might call for a transmission rebuild or replacement. Whichever one of these issues is the cause, you may have to disassemble your gearbox. It will not be cheap

 

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Baraza,

I wish to thank you for your professional advice to the motoring fraternity. The precision with which you answer questions is really enviable. Now, I have been very interested in buying either a Yoyota Noah or Voxy MPV, but the discouragement that I get from jua kali mechanics and even some of my friends makes me feel uneasy about the undertaking. One, they say the engine is not easy to service; and, two, the vehicle ground clearance is too low. Bearing in mind that this will be my first ca,r what is your advice on buying either of the two models. Should I ignore the mechanics and go ahead?

Mwenda

 

Mwenda, it is unlikely that a manufacturer will build a vehicle that is deliberately difficult to service, unless of course that manufacturer is Ferrari. We aren’t discussing Ferraris, are we? Mass-produced vehicles sold in their hundreds of thousands have to be relatively easy to work on because think of the backlog when servicing time comes: one will find a queue the front of which will be populated by people who showed up three days earlier for their service and are still waiting. What is servicing if not the replacement of fluids and some ancillaries which, by their own functions, have to be placed on the peripheries of the engine and are therefore easy to access?

On the ground clearance, only you know how extreme the conditions are in the rural areas you visit. Non-tarmacked roads will vary in quality from barely discernible goat tracks in a rollicking rock farm that demand the use of hardcore 4WDs to smoothly graded surfaces such as the ones inside Tsavo West National Park — roads so good you could drive a Ferrari on them, and the only worry you would have is if an elephant sat on your difficult-to-service sports car.

The Voxy is a Noah with Aromat. They are essentially the same car, but the Voxy has some neo-socialite cosmetic enhancement done on it, making it just a little bit fancier… and it rides lower.

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Baraza,

I drive a 1998 Toyota 110 with an automatic gearbox. I have had this car for the past two years during which it has served me well, with no breakdowns whatsoever and returning great fuel efficiency.

Lately, however, the engine has started to vibrate a lot when hot and in gear. The vibration disappears when the engine is accelerated or when the gear lever is at P or N.

I have talked to one mechanic who told me it was because the ATF was low since the engine mountings were okay, according to him. We topped up the ATF, but there was no discernible change. This vibration is irritating, given the time spent in traffic jams. What could be the problem?

Sam

 

There are two possibilities to this, Sir. First up, the transmission mounts could be in need of replacement. The disclaimer here is that more likely than not the vehicle would still vibrate while in motion if the mounts were shot, so we look at the second possibility: the transmission itself.

Automatic transmissions are very complex pieces of kit. It could be that the clutches and bands for the planetary gears (see the Hilux matter above) are not engaging/disengaging as they should, which means it could be any number of actuators and or the gear pump. It could be one of the solenoid valves malfunctioning. It could be the TCM (transmission control module). It could be an issue with the stator assembly inside the torque converter.

Such problems usually have a two-step process of solving: plug in the ECU (engine control unit) to a diagnostic machine (if the ECU and TCM are one and the same, or else just plug in the TCM) and look for an error code. And/or: open up the transmission to see if the components are working properly. This second part calls for a mechanic who knows what he is doing.

Note: take care not to overfill the transmission fluid.

After a paint job, ask them if they have lacquer; and if they know how to apply it. If they don’t then they best leave it alone: a bad lacquer looks worse than no lacquer at all. Lacquer is like a vitamin: the right amount works wonders but too much of it becomes counterproductive. The lacquer is what makes the car gleam, especially after buffing, and it acts as a trap for dust and small particles which might otherwise scour the paint

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