Isuzu NPR, NQR, NRR, GM, Mitsubishi FUSO, UD: Prevent Transmission Failure & Overheating Problems
There are three types of automatic transmissions in the Japanese imported midrange trucks. This includes Isuzu’s NPR, NQR, NRR, FRR, and FTR as well as GM’s W3500, W4500, W5500 and W6500 models, Chevrolet’s W3, W4 and W5 trucks, Mitsubishi FUSO’s FE, FG, FH, FK, and FM trucks, and UD’s 1200, 1300, 1400, 1800, 2000, 2300, 2600 and 3300 trucks.
- Jatco (primarily found in ’98 and older smaller trucks)
- Aisian-Seiki (primarily found in ’99 and newer smaller trucks)
- Allison (Allison transmissions are found in the bigger imported trucks)
The most common problem we are seeing at Seattle Transmission repair is related to overheating that leads to transmission failure in imported trucks. One cause is related to sludge build-up in the cooling system of the transmission. It can be eliminated by flushing the cooling system with a good grade of transmission cooling system flush that can be purchased at your local auto parts store. This is done by disconnecting the cooler lines of the transmission and flushing the lines and the cooler itself with a good grade of transmission flush.
Flushing the system, along with changing the fluids can extend the life of your transmission and should be done regularly. It is important to change the fluid every 35,000 -40,000 miles even if you’re not experiencing problems. Some people don’t ever change it, some people just change the oil and that results in transmission failure.
The other problem that causes transmission failure from overheating is a malfunctioning electric fan or thermostat that controls the fan. Some models are equipped with an electric fan on the transmission cooler. It is very important to make sure this fan is working properly. There is an easy way to check this: when the engine is hot, visually see if this fan is running by simply looking at it. Or you can short the thermostat wires that control this fan and make sure it is coming on properly. You should check this immediately after pulling a heavy load to make sure the fan is coming on properly to avoid transmission failure. Of course, the best way is to have it checked by a certified and fully trained professional. It is easier and cheaper to replace a faulty fan and/or thermostat than to replace a transmission.
In the last two decades, the diesel power plants offered in diesel pickups have come with ever-increasing horsepower and torque numbers. But, in order for manufacturers to meet durability standards, stronger power train components were needed. As the parent company of Allison (from 1928 to 2007), General Motors engineers knew which automatic transmission would be capable of handling its Duramax engine’s 300 hp and 520 lb-ft at the turn of the century.
Beginning with the ’01 Chevy and GMC 2500 HD and 3500 trucks, customers purchasing a Duramax-powered Silverado or Sierra had the option of backing it up with the legendary Allison transmission. No doubt, the Duramax and Allison combination provided one of the most bulletproof packages on the market, and many people bought GM trucks based on Allison’s reputation.
Breaking Into The Light-Truck Market
According to the Society of Automotive Engineers (SAE), Allison conducted extensive studies of the North American light-truck market before the Allison 1000 was on the drawing board. Noticing a torque growth in diesel engines torque rating of approximately 15 lb-ft per year (from 1990 to 1994), Allison’s engineers believed diesels would be making 470 to 510 lb-ft by 2000. And with the Duramax’s debut torque rating coming in at 520 lb-ft, we’d say they were spot-on in their power prediction.
Allison LCT 1000
Spawning from the success Allison had with its AT542 automatic transmissions in the medium-duty segment, the Allison LCT 1000 was a much-improved version to say the least. The Allison 1000 came with some key features that the AT542 lacked, such as a parking pawl, Overdrive gear, and a torque converter clutch. Production of the Allison LCT 1000 began in 1999.
Adaptive Learning and the Aftermarket
One of the most advanced features found in the Allison 1000 is its use of adaptive learning technology. The adaptive learning process refers to the transmission’s constant comparison of key shift parameters to pre-programmed (ideal) shift conditions. The electronic transmission controls then make hydraulic adjustments to assure the key shift parameters match the torque to create the ideal shift strategy for the next shift. This is done to keep the driving experience comfortable and avoids any rough shifting instances. This adaptive shifting process continues for the life of the vehicle to provide consistent, optimized shifts.
What are the most common rear differential problems and how can they be dealt with? Read to find out all about it.
One of the most important car parts, yet very less known, is the rear differential. It plays a big role in the functioning of the automobile. In this article, my aim is to specify the function of a rear differential and identify the major rear differential problems that a car owner may have to deal with.
Understanding any car problem requires you to know is a differential work and know about its basic mechanism. Before I delve into rear differential problems, let me briefly describe the role played by a rear differential. One of the most fundamental things that you need to grasp is generation and distribution of torque. Let us see the role played by a rear differential in the overall automobile mechanism.
Function of a Rear Differential
What drives a car is the torque generated in the car’s engine. This is common knowledge but very few people can explain how that torque is transmitted into the rotational movement of wheels. Let me provide a brief overview, which will also explain rear differential function.
Engine torque drives the crankshaft, which is conveyed to the drive shaft, via transmission and it ultimately reaches the wheels through the rear differential. The rear differential is made of gears and it works to control the speed of wheel rotation. When turning, wheel speeds need to differ and this is made possible by the rear differential mechanism. Whenever you make a smooth turn, your rear differential comes into play.
Modern cars come with many types of built in rear differential mechanisms. The most common ones are limited slip differentials or a locking differential which allows for a rear differential to lock. You must have noticed a pumpkin-shaped mechanism between the rear car wheels. That is where the differential is located.
Common Rear Differential Problems
After that brief overview of rear differential function let me discuss some of the most common rear differential problems that may crop up.
Rear Differential Noise
One of the most common differential problems is noise, resulting from friction between internal gears of the rear differential mechanism. This noise is more of a growling kind and becomes louder when you bank into a turn. The reason for noise may be a drop in the differential’s lubricant levels. If left unchecked, this problem can grow, ultimately resulting in a complete breakdown and major car repair. So at the slightest inkling of rear differential noise, it is best to get the mechanism checked out from a mechanic like Kings Transmission Repair. The inner mechanism of a rear differential is just too complex for most people to handle on their own. That’s why, it is best to leave rear differential problems for professionals to solve.
Rear Differential Leak
Another common rear differential problem, which often goes un-noticed is leaking of lubricant. As discussed in the previous point, if lubricant levels drop down, then friction between gears increase. Over a period of time, this may lead to major wear and tear in the gears. That’s why you need to keep an eye on rear differential leak if it ever occurs. If the lubricant level has dropped down substantially, noise may occur. You must immediately correct the leak and replenish the oil level to normal, to prevent any further wear and tear.
Hope this brief guide on rear differential problems was a helpful read. If you include rear differential maintenance into your monthly car maintenance schedule, then problems will rarely arise. At the slightest doubt of problems with the rear differential, it is best to get your car to a service center for checkup. Ignoring the signs of a bad rear differential may ultimately cost you a lot in car repairs.
Clutch diagnosis may be necessary when problems with noise or slipping have been detected. The diagnosis of clutch problems will vary depending on the type of system that is deployed on the vehicle.
Most modern vehicles have a hydraulic clutch assembly. But it is still possible to find vehicles that have a manual clutch cable operated system. Repair and diagnosis is handled very differently between the two.
Before continuing with your clutch diagnosis it is important to identify which type of system is on your vehicle. Below these two common types of systems are explained in more detail.
The important part about knowing what type you have is that a manual cable can be adjusted both for free play on the pedal as well as engagement of the clutch disc itself. The most common hydraulic systems have no such adjustments as they are built into the system.
Hydraulic clutches that are not operating properly may need components such as slave cylinders and master cylinders diagnosed or replaced. Internal seal leaks on these components can occur that will bypass hydraulic fluid without any signs of external leakage. At Kings Transmission Seattle we will diagnosis your vehicle for free.
Manual cable clutch diagnosis
A manual clutch cable looks very similar to an emergency brake cable as it is made of braided wire and covered in a plastic or vinyl sheath. One end of the cable is connected to the top of the clutch pedal.
The other side of the clutch cable is attached to the clutch fork that operates the release bearing or throw out bearing. The casing of a clutch cable is usually fastened to the firewall to provide support and proper operation.
When the clutch pedal is pushed this will disengage the clutch by moving the fork that holds the release bearing. When the pedal is released the pressure plate will clamp the clutch against the flywheel and spin the input shaft on the transmission.
Some manual cable clutch systems have an automatic self adjusting mechanism. Often this is a ratchet that is located at the top of the clutch pedal.
This ratchet is designed similar to a star wheel adjuster that has a tooth ring and a tab to hold its position. Manual clutch cable adjustments may be needed when the clutch cable develops slack due to stretching.
In the automatic adjusting systems mentioned above this should happen on its own when the clutch pedal is released. If adjustments are necessary it is recommended to follow procedures outlined in your manual for your specific vehicle as specifications and procedures will vary.
Hydraulic clutch diagnosis
In many modern cars the operation of the clutch release bearing is controlled by a hydraulic system. This provides easy operation and reduces fatigue on the driver’s clutch leg and foot without sacrificing clamping power to the flywheel.
In hydraulic clutch operation the same tasks are performed as with a manual cable system. The release bearing is operated by a slave cylinder that is controlled by hydraulic pressure and a return spring.
The two main components of these hydraulic systems would be a clutch master cylinder and the slave cylinder. The clutch master cylinder operates similar to a brake master cylinder as it has a reservoir although it is much smaller. The hydraulic system converts pedal pressure into movement.
When the clutch pedal is pushed the slave cylinder piston moves the clutch fork which disengages the clutch via the release bearing.
When the clutch pedal is released an external springs moves the slave cylinder pushrod back and allows the pressure plate to clamp the clutch disc directly to the flywheel.
My experience with hydraulic clutch diagnosis often leads me to problems in the master or slave cylinders themselves. Internal seals can fail in these components and bypass hydraulic pressure or even develop external leaks.
The small amounts of fluid contained in these systems make them difficult to bleed. Some mechanics believe that the master and slave cylinders should be replaced in pairs.
I happen to believe this as well. Often seal problems can be traced back to contaminated fluid. If this is the case then both hydraulic clutch parts should be replaced.
It never fails that when the first snow hits the Seattle area those of us with 4×4 vehicles hit the button or shift our vehicles into four wheel drive only to find out that nothing changes. Not thinking to check the 4×4 option in good weather is just human nature. Don’t feel bad your not alone. And so you know most transfer case problems are not a major repair. With the advent of computer controls we at Seattle Transmission Repair fix many of the problems with a bad fuse or controller. A Lot of the early units used vacuum lines that go bad over time. Some of the Chevy trucks and Suburbans have a control switch that goes bad and is a simple fix of just replacing the broken- worn out controller. So if you find yourself in this situation give us a call and we will get you right back on the road.
How Can I Avoid Scams and Ripoffs when Purchasing Transmission Repair?
Automatic transmission repairs are expensive; some can easily cost $2000 or more. So it’s more important than ever to find a shop that will provide quality repairs at a fair price. Here are a few ways you can avoid getting cheated when searching for a transmission repair shop:
1. Get Recommendations — Ask friends and family to recommend a shop where they were treated well and were happy with their work.
2. Look for a Professional Appearance — A clean, organized shop indicates a professional attitude. And that usually carries over into all phases of the business… including their repairs and job pricing.
3. Avoid Phone Estimates — Today it’s virtually impossible to give an accurate estimate over the phone. Any shop that will give you a price before they see the car is probably low-balling you. Expect the price to go up considerably before the job is finished.
4. Ask for a Detailed, Written Estimate — After checking your car thoroughly, the repair center should have a fairly good idea of what’s wrong with your car. They should be able to provide a written estimate that specifies what’s wrong, and what it’ll cost to repair it.
5. Look for Membership in Consumer Organizations — Most reputable shops are members of an organization or association that provides consumer arbitration in the event of a dispute, such as the AAA. ATRA or ATSG provides this service to its members.
6. Check reviews on line. Google, Dex Knows and Yelp are a few that can help in finding the right shop for you.
But reviews can be a bit deceiving. It has been our experence that most customers that are happy with Kings Transmission repair don’t leave reviews. But those that been less then happy go out of their way to leave negative reviews. You can’t make everyone happy all you can do is try.
As consumers face rising prices at the gas pumps, more and more people are looking into buying a car equipped with a manual transmission instead of an automatic. But that change may not provide the desired effect for most drivers.
That’s because today’s automatics are lighter and more efficient than those of just a few years ago. So much so that only a highly motivated driver will have any hope of wringing substantially higher gas mileage out of a manual transmission.
What’s more, the back-end costs of a manual will quickly eat away at any savings you might receive at the pump. Most drivers can expect to have the clutch replaced as often as every 30,000 miles or so. And when it comes time to sell or trade the car, they can expect a dramatic drop in value with a manual transmission.
For most people, an automatic transmission is a far better choice when buying a new car. They’re more efficient, easier to drive, and last longer than those of just a few years ago.
What ever path you pick Seattle Transmission Rebuild stands ready to repair or rebuild standard or automatic transmissions.
The CVT (Continuously Variable Transmission) in becoming increasingly popular with both Domestic and Import cars. Historically, these transmissions were limited due to their lower torque capacity; only being used in sub-compact cars with small-displacement engines. Better designs make these transmissions an option for wide range of car models with more substantial engines. The advantages of the CVT is they are compact, have fewer moving parts and have an infinite range of ratios; resulting in better fuel economy. Be careful though when it comes time to service your CVT. Using the wrong ATF (Automatic Transmission Fluid) can cost you dearly.
CVTs use two steel pulleys and a steel belt made of multiple segments. The pulleys move in a fashion that causes the belt to ride on different locations of the pulleys, resulting in a ratio change. This metal-to-metal contact between the pulleys and belt require a specially-formulated fluid to reduce wear. Using an ATF not designed for use in a CVT will result in premature wear and drivability problems. Although the CVT is simple in design they are very expensive to repair; commonly in the $3,000 range or higher.
If you service your CVT transmission make you use fluid that states “CVT” on the container. Or you can bring it to Seattle Transmission repair and we will service your transmission.
You’re driving alone on a dark road, when all of a sudden the Check Engine light on the dash comes on. Oh, no! What do you do now?
In most cases, relax. The Check Engine light is rarely an emergency. It indicates that the computer recognized a problem in one of its systems. Very often that problem is emissions related. But it probably isn’t something that’ll cause any real damage to your car or a safety issue for you. And your car won’t stop running all of a sudden.
After you get home, you’ll want to call your local repair shop and make an appointment to have the system checked. If the light goes out, it probably means the problem is gone for now, but the computer still may have stored a diagnostic trouble code that your technician can retrieve and diagnose.
Your local ATRA Member shop can check your car’s computer system for codes, and diagnose any computer system problems you may experience.
To find the ATRA Member near you, click the Shopfinder link.
If you find yourself with a trouble light call us at Kings Transmission 206-624-1859 and we will scan your car for free.
CVT Transmissions, what they are and how they work.
A continuously variable transmission, or CVT, is a type of automatic transmission that provides more useable power, better fuel economy and a smoother driving experience than a traditional automatic.
Driving a car with a CVT
The controls for a CVT are the same as an automatic: Two pedals (no clutch) and a P-R-N-D-L-style shift pattern. But while an automatic transmission has a set number of gear ratios (a.k.a. speeds), usually 4, 5 or 6, the CVT can constantly change the relationship of engine speed to car speed. When driving a car with a CVT, you never hear or feel the transmission shift — it simply raises and lowers the engine speed as needed, calling up higher engine speeds (or RPMs) for better acceleration and lower RPMs for better fuel economy while cruising.
Many people find the CVT disconcerting at first because of the way cars with CVTs sound. When you step on the accelerator, the engine races as it would with a slipping clutch or a failing automatic transmission. This is normal — the CVT is adjusting the engine speed to provide optimal power for acceleration.
How the CVT works
Traditional transmissions use a gear set that provides a given number of ratios (or speeds). The transmission (or the driver) shifts gears to provide the most appropriate ratio for a given situation: Lowest gears for starting out, middle gears for acceleration and passing, and higher gears for fuel-efficient cruising.
Though there are several types of CVT’s, most cars use a pair of variable-diameter pulleys, each shaped like a pair of opposing cones, with a metal belt or chain running between them. One pulley is connected to the engine (input shaft), the other to the drive wheels (output shaft). The halves of each pulley are moveable; as the pulley halves come closer together the belt is forced to ride higher on the pulley, effectively making the pulley’s diameter larger. Changing the diameter of the pulleys varies the transmission’s ratio (the number of times the output shaft revolves for each revolution of the engine), in the same way that a 10-speed bike routes the chain over larger or smaller gears to change the ratio. Making the input pulley smaller and the output pulley larger gives a low ratio (a large number of engine revolutions producing a small number of output revolutions) for better low-speed acceleration. As the car accelerates, the pulleys vary their diameter to lower the engine speed as car speed rises. This is the same thing a conventional automatic or manual transmission does, but while a conventional transmission changes the ratio in stages by shifting gears, the CVT continuously varies the ratio — hence its name.
Advantages of the CVT
Engines do not develop constant power at all speeds; they have specific speeds where torque (pulling power), horsepower (speed power) or fuel efficiency at their highest levels. Because there are no gears to tie a given road speed directly to a given engine speed, the CVT can vary the engine speed as needed to access maximum power as well as maximum fuel efficiency. This allows the CVT to provide quicker acceleration than a conventional automatic or manual transmission while delivering superior fuel economy.
Disadvantages of the CVT
The CVT’s biggest problem has been user acceptance. Because the CVT allows the engine to rev at any speed, the noises coming from under the hood sound odd to ears accustomed to conventional manual and automatic transmissions. The gradual changes in engine note sound like a sliding transmission or a slipping clutch — signs of trouble with a conventional transmission, but perfectly normal for a CVT. Flooring an automatic car brings a lurch and a sudden burst of power, whereas CVTs provide a smooth, rapid increase to maximum power. To some drivers this makes the car feel slower, when in fact a CVT will generally out-accelerate an automatic.
Automakers have gone to great lengths to make the CVT feel more like a conventional transmission. Most CVTs are set up to creep forward when the driver takes his or her foot off the brake. This provides a similar feel to a conventional automatic, and serves as an indicator that the car is in gear. Other CVTs offer a “manual” mode that simulates manual gear changes.
Because early automotive CVTs were limited as to how much horsepower they could handle, there has been some concern about the long-term reliability of the CVT. Advanced technology has made the CVT much more robust. Nissan has more than a million CVTs in service around the world and uses them in powerful cars such as the 290 horsepower Maxima, and says their long-term reliability is comparable to conventional transmissions.
Seattle Transmission Repair now offers repair and rebuilds on all makes of CVT transmissions.