S-Chassis.com - Removal/Welding/Installing Differential

Disclaimer: Don't weld your diff if you plan on just going from home to school etc. All of the steps I performed are my way of doing it, feel free to alter any steps if it's easier for you. this is a one man job but a friend could help at various points. I did this write-up for those who chose to do so. if you are against it keep your comments to yourself please
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This is my second welded diff. the first one broke loose because i had an poor low voltage flux welder. Here it is.

Tools & Material

*to remove diff*
http://img125.imageshack.us/img125/2...5270358ll1.jpg

17mm socket/wrench
14mm wrench
12mm wrench
pry bar
hammer
1/2 breaker bar
floor jack
jack stands
wheel chock
drill/wire wheel(optional)
goggles(optional)
Impact gun(optional)

*to weld diff*
http://img106.imageshack.us/img106/2...5270359rg5.jpg
Mig welder ( at least 110 Volts)
safety equipment
chisel( thin flathead)
magnet
2 bottles of gear oil
2 cans of brake cleaner
RVT red,copper or black
Drain pan
simple green(to clean all that damn gunk/grease on bottom of car)
Propane Torch ( optional)
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Removal

1. insert wheel chocks under front wheels and place Jack under diff toward the center to raise the car
http://img64.imageshack.us/img64/4424/kp5270351dq0.jpg
2. place jack stands
http://img250.imageshack.us/img250/8...5270354mm9.jpg
3. if you feel a need to you can remove rear exhaust hangers to free up space
http://img125.imageshack.us/img125/4...5270360bz6.jpg
4. remove sway bar mounts only ( will give you needed room to clear pinion input)
http://img529.imageshack.us/img529/5...5270379kx1.jpg
5. drain fluid now or just allow it to gush out when you remove the rear cover, use 1/2 breaker bar
http://img240.imageshack.us/img240/4...5270372km5.jpg
6. with the e-brake up, proceed to remove the 6 12mm bolts from the half-shafts, you will have to let the e-brake down in order to rotate the half shaft and get the others.
http://img159.imageshack.us/img159/8...5270367vk4.jpg
7. once you have removed the bolts, you will need the pry bar to remove right half shaft (only) due to notch
http://img131.imageshack.us/img131/2...5270369fe2.jpg
8. Remove 4 bolts from drive shaft, you will need a buddy to pull and release e-break or use thin rod or long 3/8 extension.
http://img184.imageshack.us/img184/4...5270378oa3.jpg
9a. before removing the 4 nuts that bolts the diff to the rear sub frame,you may have to blast rust off so that you will not strip the nuts like so.
http://img443.imageshack.us/img443/32/kp5270376xd4.jpg
9b. after you do that proceed to remove them using the following methods.
http://img255.imageshack.us/img255/2...5270373aw8.jpg
you will need shallow socket to get upper bolts with breaker bar due to gas tank
http://img65.imageshack.us/img65/1662/kkp5270374yg1.jpg
10a. Place jack toward back of diff like so, and lightly jack the diff against the tunel
http://img184.imageshack.us/img184/884/kp5270390pl6.jpg
10b. remove two 17mm bolts holding diff to sub frame
http://img163.imageshack.us/img163/6...5270365nn9.jpg
10b. place hand in this position, with your elbow bent at 90deg angle and slowly lower diff
http://img114.imageshack.us/img114/6...5270396yo8.jpg

Welding

1. Remove bolts from diff
http://img174.imageshack.us/img174/9...5270398mt2.jpg
2. use pry bar with hammer to remove cover ( be careful)
http://img443.imageshack.us/img443/2...5270400ty4.jpg
3. Clean up rear cover and apply liquid gasket. do this now and it will be very firm during re-installation
http://img131.imageshack.us/img131/5...5270403by3.jpg
4a. As you can see the gears are coated with oil ( a good thing lol) but you must dry them using brake cleaner before you can weld. spray the spider gears only, don't directly spray the Ring and Pinion gears
http://img116.imageshack.us/img116/6...5270405vw6.jpg
4b. After about 2 min, the gears will be dry and look like this. pour the brake cleaner out or else you will get an fireball.( optional but recommended)Take and wet towel cut into strips and insert inside of bolt holes and around bearing like so to protect against sag. also the pieces on the bearing will have to be soaked at least 2-3 times because the heats will dry them up and catch fire.
http://img113.imageshack.us/img113/7...5270409tk6.jpg
5. With-in the enlarged portion of the picture, you want to fill the section with the orange line in first with a nice strong continuous bead. the area with in the red circle must be filled/joined in order to increase strength. depending on your spool size, you may need a second. i used one spool per side. you will repeat this action 3 more times on this side and you must rotate the diff and complete the other side. IF you have a Propane torch pre heat the gears before welding
http://img112.imageshack.us/img112/7...5270407qt4.jpg
6. once you have welded the corner of all the gear, for extra strength you want to run about two to three layers of continuous bead all the way around, start low and build your way up. i didn't get a picture of the underside of the Ring Gear but it is welded the red line is imaginary, every once in a while use your flathead chisel to knock loose sag away,
http://img124.imageshack.us/img124/5...5270419yv7.jpg
7. once you are done welding, pour a bit of gear oil on the gears becuase now you may have to un-seize them.. don't get scared.. the gears are stiff because there was no fluid present when you are welding and the heat gets pretty high. All you have to do is place a 17mm wrench on the bolts of the Ring gear and give it a few manly taps and it will free up again an began to spin freely

8. now take your second can or brake cleaner and blast all of the debris out very good. you don't want sag getting into your bearings. If you have the magnet it will be awesome for getting all of the metal shavings and sag out of the differential carrier. now empty the mixture of gear oil and brake cleaner from the diff housing

10. after you think you got enough of it out, pour one bottle and an half of fluid inside the diff while the cover is off, this will make life a little easier lol

9. Clean the matting surface on the differential housing using a little brake cleaner and a scraper if need be and place rear cover on and follow color/number pattern
http://img443.imageshack.us/img443/3...5270420cw8.jpg

Installation

1. Position diff under car, rest the pinion input on the sway bar like so ( if you don't have a buddy to pick it up for you while you jack it up)
http://img19.imageshack.us/img19/9650/kp5270423my7.jpg
2. Now you must lift the back of the diff up and place jack under diff. it will help if you have the jack already preset to a pretty decent hieght. the diff is really easy to handle with the front end of it resting on the sway bar.
http://img79.imageshack.us/img79/5800/kp5270424yg4.jpg
http://img69.imageshack.us/img69/5327/kp5270429lj0.jpg
3. once you have the 4 bolts through, lightly jack the diff against the body of the car. and insert the two 17mm bolts at the front of the diff. but don't tighten them all the way becuase you have to fully tighten the diff cover bolts first. the reason being is, you want the cover as flush as possible against the sub frame. follow the color pattern, you can start on any nut that you wish.
http://img251.imageshack.us/img251/3...5270366gh8.jpg
(trick: you can double a wrench up to increase the amount of TQ you can apply)
http://img238.imageshack.us/img238/6...5270433rw5.jpg
4. now completely tighten your 17mm bolts at the front of the diff

5. now move your half shafts back into place. in order to line the bolt holes up you will have to release your e brake and rotate your wheels becuase the diff will be hard to turn now. remember our notch on the right side?? you will need to place the notch above the half shaft like so and use your pry bar to pop it back in.
http://img105.imageshack.us/img105/7...5270435oo5.jpg
6. now you will insert all of the bolts back into the half shafts on both side ( 12 in total)
http://img69.imageshack.us/img69/3324/kp5270436dd8.jpg
7. Next you will you will re-attach the drive shaft like so. you can have buddy release/pull the e-brake so that you can rotate the wheel and rotate the bolt holes on the pinion input for easy access/tightening
http://img411.imageshack.us/img411/498/kp5270440km5.jpg

8. last step will be to reinstall sway bar bushings using 14mm wrench and if you have as much gunk and grease like i did you are going to soak the car with simple green and blast it all off with pressure washer.

Thank You for Viewing and go get sideways
http://img.photobucket.com/albums/v2...s/HPIM0645.jpg

http://img211.imageshack.us/img211/7771/coolaidaq5.png