So one night I get out of work around 1:30 am and not quite ready to go home. My friend Mark wanted to go for a punch ride in the Grand Am to check out the new exhaust system. At that time the car had a 400, with turbo 400 and 3:73, 7.5 inch rear. We head down the main road, turn left, go a few blocks, and then on the return road I decide to wind out the engine and show him how quick the car is. The road is right behind a development with nice quiet homes. I wind out all three gears and right at about 6,000 rpm in 3rd gear there's literally an explosion, instantly the engine revs much higher, the car starts to skid and then jumps, then suddenly the car is rolling again (at about 115 mph).
At the same time as the explosion, both myself and Mark are getting sprayed in the face with pieces of metal and concrete that are coming through a new gaping hole in the floor- where my console apparantly just broke in half from the explosion. I hang on to the wheel and get the car pulled over and stopped, then start making sure I have all my toes etc.
I get out of the car, look underneath, and see a small fire from transmission fluid burning on whats left of my new exhaust pipes. Looking down the road I see steaming pieces of the transmission and driveshaft for about 1/8th of a mile. I put the fire out, pop the hood and look behind the engine, to see that the transmission is completely gone.
We decide to walk back to my job and get to a payphone (long before I had a cell phone). Dad comes to get us (now 2am) and we get to the car the same time as 2 fire trucks, ambulance, and 3 police cars. The people who witnessed the explosion said it woke them out of bed and to them it sounded like a train accident, they expected a tractor trailer to be flipped or something horrible.
We collected the pieces of the transmission, all we found were a few small pieces of bellhousing and the main rear section (turbo 400). The driveshaft was literally twisted to less than 1/2 the original length, looked like a twizzler. The starter was ripped off the engine, the flywheel and torque converter were bent so badly that they cracked the back of the engine block.
After studying everything I figured out what happened. At about 115 mph the small bolt broke that holds the pin in place, which holds the spider gears in the rear axle. That large steel pin instantly locked the rear axle while the engine was maxed at peak HP, at 6,000 rpm. At that point the driveshaft twisted, and the torque on the splines in the driveshaft yoke was strong enough to rip the transmission off the engine. At that point the transmission started spinning violently and destroyed the floor and console. For some reason the pin in the rear axle slid back enough to release the rear, and the rear wheels began rolling again. This all happened in about 1 second. - After that the transmission and driveshaft fell under the car which slightly catapulted the rear of the car enough to make the car jump. It also destroyed my exhaust system.
Overall I had to replace the transmission, driveshaft, spider gear shaft locking bolt, starter, engine, flywheel, torque converter, console, exhaust, and patch the floor- all because of a bolt that cost about $1.
At the same time as the explosion, both myself and Mark are getting sprayed in the face with pieces of metal and concrete that are coming through a new gaping hole in the floor- where my console apparantly just broke in half from the explosion. I hang on to the wheel and get the car pulled over and stopped, then start making sure I have all my toes etc.
I get out of the car, look underneath, and see a small fire from transmission fluid burning on whats left of my new exhaust pipes. Looking down the road I see steaming pieces of the transmission and driveshaft for about 1/8th of a mile. I put the fire out, pop the hood and look behind the engine, to see that the transmission is completely gone.
We decide to walk back to my job and get to a payphone (long before I had a cell phone). Dad comes to get us (now 2am) and we get to the car the same time as 2 fire trucks, ambulance, and 3 police cars. The people who witnessed the explosion said it woke them out of bed and to them it sounded like a train accident, they expected a tractor trailer to be flipped or something horrible.
We collected the pieces of the transmission, all we found were a few small pieces of bellhousing and the main rear section (turbo 400). The driveshaft was literally twisted to less than 1/2 the original length, looked like a twizzler. The starter was ripped off the engine, the flywheel and torque converter were bent so badly that they cracked the back of the engine block.
After studying everything I figured out what happened. At about 115 mph the small bolt broke that holds the pin in place, which holds the spider gears in the rear axle. That large steel pin instantly locked the rear axle while the engine was maxed at peak HP, at 6,000 rpm. At that point the driveshaft twisted, and the torque on the splines in the driveshaft yoke was strong enough to rip the transmission off the engine. At that point the transmission started spinning violently and destroyed the floor and console. For some reason the pin in the rear axle slid back enough to release the rear, and the rear wheels began rolling again. This all happened in about 1 second. - After that the transmission and driveshaft fell under the car which slightly catapulted the rear of the car enough to make the car jump. It also destroyed my exhaust system.
Overall I had to replace the transmission, driveshaft, spider gear shaft locking bolt, starter, engine, flywheel, torque converter, console, exhaust, and patch the floor- all because of a bolt that cost about $1.
Catastrophic rear end failure at 6000RPM....I laugh because its always funnier when someone else blows their drive line right out the back of their car. If that happened to me I probably wouldn't think it was so funny. at the time anyways.
