747mopar
Well-Known Member
Since I like doing things myself I thought I'd start a thread showing how to put an 8 3/4 pig together in hopes that others will see that it doesn't take a rocket scientist to do it. One big problem........... I don't know how to do it haha, for that reason I'm calling on the help of the more experienced guys to police this thread and correct and add to it so please by all means jump in.
First off some background, I recently installed a Viper T56 (6 speed standard) in my 69 Charger that has a 2.66 1st and .5 6th so I've put a couple hundred miles on it this Spring getting an idea of what gearing will do the trick. I've calculated my 2,000 rpm cruising, 6,000 rpm shift points and the top speed in 4th for a 12 second pass (my goal) and 4:30's are the best match. I've got 3:55's in a 742 case in it now but have been holding onto this 489 for this occasion so let's begin.
First off while waiting on parts I tore down the clutch unit itself for inspection and cleaning, it's best to mark all of the parts so that everything goes back together exactly as it was. Also pay attention to the plate arrangement (some are flat and some cupped and need to be put back together as they were. Mine ended up looking really good inside so it's just getting a cleaning.
Next was getting the carrier bearings off....... What a PITA! The leave virtually no room for a bearing splitter so I carefully ground the bearing down to paper thin on one side making sure not to get into the carrier (you'll see it turning purple once your close). Of coarse you want to do this before you clean it. Once cleaned I pressed the new bearings on.
Probably one of the biggest things to make sure you do is have a coupe spare axles on hand to keep the splines lined up while bolting it back together (not doing this would mean you'd never get your axles in).
On to getting the pinion setup, the rear originally had the shim behind the larger pinion bearing outer race but the kit has shims that go behind the actual bearing itself (same difference). I measured the original and put the same amount of shim behind the bearing for a starting point (will most likely take a few stabs at it to get it right). Here's the problem with not having the factory tools, once you put the large bearing on the pinion it's a real pain to get off so I chose to take Cranky's advice and buy and extra bearing (both Timkens) and hone one just for doing gear setups so it's easily removable for getting the pinion depth set right.
Now for setting the pinion bearing preload, I bought a crush sleeve eliminator kit that came with 2 sleeves (one longer than the other). I measured the original sleeve and found one sleeve was really close and the other quite a bit shorter so I added the appropriate amount of shims to match the original for a starting point. First try was sloppy so I used a dial indicator to give me an idea of how much needed to come out and tried again. It took a few tries but I ended up with one .014 shim to achieve the 20-30 inch pound turning torque stated in the manual.
Before installing the ring gear I took a honing stone to it and know why they suggest doing this (a few minor dings). A few minor dings will hold the ring gear out because of the raised metal, once hammered flat from abuse you have a loose fit.
- - - Updated - - -
Hoping to finish it Friday.
First off some background, I recently installed a Viper T56 (6 speed standard) in my 69 Charger that has a 2.66 1st and .5 6th so I've put a couple hundred miles on it this Spring getting an idea of what gearing will do the trick. I've calculated my 2,000 rpm cruising, 6,000 rpm shift points and the top speed in 4th for a 12 second pass (my goal) and 4:30's are the best match. I've got 3:55's in a 742 case in it now but have been holding onto this 489 for this occasion so let's begin.
First off while waiting on parts I tore down the clutch unit itself for inspection and cleaning, it's best to mark all of the parts so that everything goes back together exactly as it was. Also pay attention to the plate arrangement (some are flat and some cupped and need to be put back together as they were. Mine ended up looking really good inside so it's just getting a cleaning.
Next was getting the carrier bearings off....... What a PITA! The leave virtually no room for a bearing splitter so I carefully ground the bearing down to paper thin on one side making sure not to get into the carrier (you'll see it turning purple once your close). Of coarse you want to do this before you clean it. Once cleaned I pressed the new bearings on.
Probably one of the biggest things to make sure you do is have a coupe spare axles on hand to keep the splines lined up while bolting it back together (not doing this would mean you'd never get your axles in).
On to getting the pinion setup, the rear originally had the shim behind the larger pinion bearing outer race but the kit has shims that go behind the actual bearing itself (same difference). I measured the original and put the same amount of shim behind the bearing for a starting point (will most likely take a few stabs at it to get it right). Here's the problem with not having the factory tools, once you put the large bearing on the pinion it's a real pain to get off so I chose to take Cranky's advice and buy and extra bearing (both Timkens) and hone one just for doing gear setups so it's easily removable for getting the pinion depth set right.
Now for setting the pinion bearing preload, I bought a crush sleeve eliminator kit that came with 2 sleeves (one longer than the other). I measured the original sleeve and found one sleeve was really close and the other quite a bit shorter so I added the appropriate amount of shims to match the original for a starting point. First try was sloppy so I used a dial indicator to give me an idea of how much needed to come out and tried again. It took a few tries but I ended up with one .014 shim to achieve the 20-30 inch pound turning torque stated in the manual.
Before installing the ring gear I took a honing stone to it and know why they suggest doing this (a few minor dings). A few minor dings will hold the ring gear out because of the raised metal, once hammered flat from abuse you have a loose fit.
- - - Updated - - -
Hoping to finish it Friday.
Btw, you might find it's easier to paint the pinion with the checking grease and then rotate it though the ring gear......
