My Saab's a real whiner!
My 1983 Saab 900 has developed a peculiar noise after 118,000 miles. At speeds above 35 mph there is a whine that sounds just like tires on an old steel grate. As the speed of the car increases, the pitch, but not the volume of the whine increases. The noise only occurs when the car is under load, not when I'm coasting or braking, and it remains constant regardless of what gear I'm in. My friend says it's the "final drive." What is that, and is he right?
TOM: This Saab may very well be on it's final drive, Bill. Actually, the final drive is what used to be known as the differential. More colloquially, it was called the "rear end," but on front wheel drive cars, it's now in the front end. They can't call it the "front end," because that's what they call the steering components, so they call it the "final drive."
RAY: Ah, the good old days, when a rear end was in the rear. In any case, Bill, front drive cars have what's called a "transaxle." The transaxle houses the transmission and the final drive. The final drive delivers power from the transmission to the axles. It also allows for the different speeds of the wheels when you're going around turns.
TOM: Your transaxle probably developed an oil leak somewhere along the line. All the gearbox oil leaked out, and the gears in the final drive are now whining for want of lubrication. Depending on how long you've been out of oil, the damage to the transaxle may be partial or complete.
RAY: You have two choices. You can try putting three or four quarts of oil in the gearbox and keep driving. It will probably make the noise go away, and as long as you keep an eye on the oil level, you're not going to do any further damage. It will, of course, grind to a halt some hot afternoon when you're trying to pass a BMW.
RAY: If you really love this car, and want to keep it for another 118,000 miles, you should just go ahead and have the transaxle rebuilt. But be warned, if you thought the whine of the final drive was loud, wait till you hear yourself whine after you get that bill!