I was wondering if anyone could explain to me how a rearend and all the gears work. Maybe someone could point to the right direction as far as some info. goes anything would be helpful. Also what is a posi rearend. New to the world of really fixing and restoring cars, I know the basics but still need alot more education. thanks Jerome
http://home.cmaaccess.com/~scodon/may2005.htm Check out my website, and scroll down a bit. There is a picture of my rear-end disassembled so you can see the insides (posted below). The big piece on the right fits into the other piece so that the gears mesh. The bearings on the right piece fit in the grooves on the rear piece and caps go over them to hold it all together. Inside the cone piece are 4 "spider gears" that allow only one shaft or the other to get the majority of the power. This is the hardes part to visualize without actually seeing it and moving it by hand. The two axles come into the cone piece, and can move independently of each other, but when they do, the spiders rotate around them both. That is called an "open" or non-posi rear. This is why when you get stuck in the mud or sand, one wheel spins like crazy, always the one in the deepest hole, while the one on the solid ground is spinning freely and not moving the car...the spiders are letting only the freed axle spin and not letting any power go to the wheel that has the traction. I took the spiders out, and put in a solid joint that had splines so that each axle would slide into it and they would join together and not be able to turn separately. This joint was called a "spool" and creates true POSI. There are other ways to put things in the cone that will let each axle spin different amounts before they stop slipping and then lock up to become a "limited slip posi". The gearing is determined by the number of teeth on the small gear in the back piece divided into the number of teeth in the larger gear on the cone. This is a 2.79 gear combo, I swapped for a 3.80 gear combo. The new one had 38 teeth on the big gear and only 10 teeth on the smaller "pinion" gear. The pinion gear is attached to the drive shaft, and when it turnes, it slips along the curved teeth on the other gear causing a 90 degree transfer of power, again, easier to see it in person than visualize with words. Hope that helps, and doesn't just confuse you more. Really, it helps most to take one apart and mess with it so you can see how they work.
Here are the spider gears. They would be inside the cone part with a drive axle in each of the two larger gears with the splines... If you think about it, you might be able to visualize how putting pressure against one gear by spinning it clockwise would just cause the other to spin the opposite direction, which is why if you jack up the rear of the car and rotate one tire, the opposite tire spins the opposite way. IF you leave one wheel on the ground, then you wont be able to spin the raised tire (if it is in gear, if in neutral, it will force the drive shaft to spin). Hope that helps
http://auto.howstuffworks.com/differential.htm You could also try this link. Around pages 5+ there are actual animations that show you how it works. http://auto.howstuffworks.com/differential.htm
I gave this some serious discussion, simply because I have always been confused about exactly how the differential worked as well. Even after working on two now, it is still a little difficult to "conceptualize" it in my head. I know where this guy is coming from. By the way, I can only juggle three items at a time, so that fourth spider would end up on a toe or through a windshield
Really helpful Thanks for the help and the in depth discussion. It wasn't neccessary to trouble yourself on my accord, but it really helped me get a better understanding. I am going to buy a rearend this weekend and tear it apart. Once again thanks for the help, MUCH APPRECIATED. thanks Jerome
Tear it apart one piece at a time, then mess with the rotation and see what makes what move. That is the best way to get an idea how the things work. they seem like a simple concept, but really, differentials are kinda complicated. Try to rebuild one sometime...the tolerances are VERY close and specific. Makes a fun (but scary) weekend project!
