So I known for a while that my Viscous coupling was toast, so I sourced a used one from a board member, (thanks pal!) and decided to get to work today. My current tcase had no leaks, but the vc was toast.
To start off today, I did a jack test, massive fail.
So here we go.
Get your shit together.
I had a new gasket, molykote br2, and some Curil k2 ready to go thanks to Williamtii
Remove exhaust. This is great, cause I have one of those ebay IE clone exhausts ready to throw in. My car since I got it has had a rusty piece of crap glasspack on it that was loud as hell. Psyched to be rid of that.
Remove rear driveshaft cover and undo the rear driveshaft at the guibo behind the tcase. 3 bolts and you can slide the shaft back and down.
Throw a jack under the transmission and raise it up to hold the tranny and engine straight, remove the tcase mount bolt that goes through the cross member. Remove cross member. Lower jack until you can see all the bolts holding the tcase together.
Make sure you can get the fill plug out of the tcase. It is a huge hex key, can't remember what size. I had one laying around.
At this point I started prepping the half of the tcase with the VC sent to me by WilliamTii (sorry if I got your screen name wrong...)
He was nice enough to send me a small amount of Curil K2 for the rear driveshaft of the case, a seal for the rear, and a bit of Molykote br2.
First step was to use remove the nut holding the flange on, then use a 3 jaw puller to remove the flainge. A bit of tapping with a hammer, and the drive shaft, and VC dropped right out.
Don't lose the washer that goes on after the VC
Here is what the half of the tcase looks like with the shaft removed. Now is a good time to make sure the gasket surface is nice and clean, no scratches.
That first bearing that you see has a thin conical washer between it and the tcase housing.
Next you need to remove the old seal and install a new one. I used the same 30mm socket I used for the flange bold to hammer the seal back in.
New seal in place.
Now you can put the drive shaft, VC and washer back into the tcase housing
Here are the parts before putting them together. Make sure the output splines on the shaft are clean.
together ready to go in.
more pics
Next take your Curil K2 and coat the inside of the output flange before sliding it onto the output splines of the drive shaft.
With the flange spline nicely coated slide it as far onto the shaft as you can, being careful not to damage the new seal. Might be a good ideal to put a little oil on the seal to help it seat on the flange.
Getting the drive shaft and the VC all the way into the housing and the flange onto the drive shaft was a bit of a hassle, I ended up popping it a couple of times with a sledge (maybe not preferred technique) with the output shaft suspended using a vise with the flange set on top of the vise. A couple whacks (not too hard mind you) and everything was seated nicely, the nut threaded on all the way, and there was minimal play in the shaft and the housing. Everything spun freely.
Flange in place, note K2 sealant and nut threaded all the way down, with the locking spot hammered in.
The very small round gasket for the middle of the tcase is no longer availabel, I reused the old one, and used some gasket maker to keep it in proper place.
Now that your good VC and back half of the TC are good to go, time to get under the car and finish getting the bad VC out. Go around the TCase and remove all of the hex key bolts holding the two halves together. I had one cranky one that I had to cut off. After stripping that one, I made sure the hole for the hex key was clean, and gave each one a sharp rap with the hammer before attempting to pull them out. All the rest came out easily.
In this photo you can't see them all, but really all of them are pretty easy to get to with a couple extensions.
A bunch of whacking and pulling (those dowels are tight!) and the back half eventually came off.
Here is what you see. Note the small roller bearing at the end of the shaft.
Now there seems to be a lot of minconceptions out there about how the tcase works. Here is an EXCELLENT link on how it works.
http://www.garlington.biz/Ray/BMW/xfercase.htm
Basically, pretend there is no VC for a moment. The power comes in via input shaft and drives the planet gears. The rear drive shaft engages the planet gears on the outside. The Front drive gear is the sun gear.
So planet gears come in with force, and the front and rear spin at the same speed, BUT the rear is travelling a longer distance (outside of planet gears) so is therefore receiving more power. Power = Force x distance. So it is the planetary gear system that is determine the power split in the system. Now add in the VC. The inside of the VC is attached to the output shaft. The outside of the VC engages with the large bell looking thing attached to the front chain drive gear. This only comes into play when one axle F or R begins to slip, transferring power to the one that isn't slipping. Most of the time it isn't doing too much.
Where were we? Oh yeah, here is the half with the bad VC. Notice the black stuff from the toasted VC inside the gear. Also note how my gasket came out nice and clean, I was lucky, the mating surface on the half in the car was super clean.
Here is the clean ready to go one.
So now all you have to do is put the back half on, and that really wasn't too bad. Just be careful not to rip the gasket, and close everything up, add fluid to tcase, put exhaust on... and you are done.
I have the case closed up, but still have to put everything back together, and will do that tomorrow morning. Along with my new exhaust and a couple other goodies.
More pics to come tomorrow.....
To start off today, I did a jack test, massive fail.
So here we go.
Get your shit together.
I had a new gasket, molykote br2, and some Curil k2 ready to go thanks to Williamtii
Remove exhaust. This is great, cause I have one of those ebay IE clone exhausts ready to throw in. My car since I got it has had a rusty piece of crap glasspack on it that was loud as hell. Psyched to be rid of that.
Remove rear driveshaft cover and undo the rear driveshaft at the guibo behind the tcase. 3 bolts and you can slide the shaft back and down.
Throw a jack under the transmission and raise it up to hold the tranny and engine straight, remove the tcase mount bolt that goes through the cross member. Remove cross member. Lower jack until you can see all the bolts holding the tcase together.
Make sure you can get the fill plug out of the tcase. It is a huge hex key, can't remember what size. I had one laying around.
At this point I started prepping the half of the tcase with the VC sent to me by WilliamTii (sorry if I got your screen name wrong...)
He was nice enough to send me a small amount of Curil K2 for the rear driveshaft of the case, a seal for the rear, and a bit of Molykote br2.
First step was to use remove the nut holding the flange on, then use a 3 jaw puller to remove the flainge. A bit of tapping with a hammer, and the drive shaft, and VC dropped right out.
Don't lose the washer that goes on after the VC
Here is what the half of the tcase looks like with the shaft removed. Now is a good time to make sure the gasket surface is nice and clean, no scratches.
That first bearing that you see has a thin conical washer between it and the tcase housing.
Next you need to remove the old seal and install a new one. I used the same 30mm socket I used for the flange bold to hammer the seal back in.
New seal in place.
Now you can put the drive shaft, VC and washer back into the tcase housing
Here are the parts before putting them together. Make sure the output splines on the shaft are clean.
together ready to go in.
more pics
Next take your Curil K2 and coat the inside of the output flange before sliding it onto the output splines of the drive shaft.
With the flange spline nicely coated slide it as far onto the shaft as you can, being careful not to damage the new seal. Might be a good ideal to put a little oil on the seal to help it seat on the flange.
Getting the drive shaft and the VC all the way into the housing and the flange onto the drive shaft was a bit of a hassle, I ended up popping it a couple of times with a sledge (maybe not preferred technique) with the output shaft suspended using a vise with the flange set on top of the vise. A couple whacks (not too hard mind you) and everything was seated nicely, the nut threaded on all the way, and there was minimal play in the shaft and the housing. Everything spun freely.
Flange in place, note K2 sealant and nut threaded all the way down, with the locking spot hammered in.
The very small round gasket for the middle of the tcase is no longer availabel, I reused the old one, and used some gasket maker to keep it in proper place.
Now that your good VC and back half of the TC are good to go, time to get under the car and finish getting the bad VC out. Go around the TCase and remove all of the hex key bolts holding the two halves together. I had one cranky one that I had to cut off. After stripping that one, I made sure the hole for the hex key was clean, and gave each one a sharp rap with the hammer before attempting to pull them out. All the rest came out easily.
In this photo you can't see them all, but really all of them are pretty easy to get to with a couple extensions.
A bunch of whacking and pulling (those dowels are tight!) and the back half eventually came off.
Here is what you see. Note the small roller bearing at the end of the shaft.
Now there seems to be a lot of minconceptions out there about how the tcase works. Here is an EXCELLENT link on how it works.
http://www.garlington.biz/Ray/BMW/xfercase.htm
Basically, pretend there is no VC for a moment. The power comes in via input shaft and drives the planet gears. The rear drive shaft engages the planet gears on the outside. The Front drive gear is the sun gear.
So planet gears come in with force, and the front and rear spin at the same speed, BUT the rear is travelling a longer distance (outside of planet gears) so is therefore receiving more power. Power = Force x distance. So it is the planetary gear system that is determine the power split in the system. Now add in the VC. The inside of the VC is attached to the output shaft. The outside of the VC engages with the large bell looking thing attached to the front chain drive gear. This only comes into play when one axle F or R begins to slip, transferring power to the one that isn't slipping. Most of the time it isn't doing too much.
Where were we? Oh yeah, here is the half with the bad VC. Notice the black stuff from the toasted VC inside the gear. Also note how my gasket came out nice and clean, I was lucky, the mating surface on the half in the car was super clean.
Here is the clean ready to go one.
So now all you have to do is put the back half on, and that really wasn't too bad. Just be careful not to rip the gasket, and close everything up, add fluid to tcase, put exhaust on... and you are done.
I have the case closed up, but still have to put everything back together, and will do that tomorrow morning. Along with my new exhaust and a couple other goodies.
More pics to come tomorrow.....
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