Making your Q45 VLSD into a welded diff

[SATAN]

I know you are asking yourself "Why the hell would you want to do that?" Well, simply because the VLSD sucks.

 

My initial thought was to take the Viscous coupling and just drill some holes in it and plug weld them where the spine section meets the rest of the assembly. Not a good idea in my opinion. To weak. Then I though about it. You have to keep both sides of the viscous coupling spinning at the same time to make it solid. SO.... you take the washer that is in the middle of the viscous coupling and drill/punch it out. Now you can take the longer input shaft and plug it into the opposite side it would normally go in. This way one shaft slides all the way through both sides of the coupling making it a solid piece. Once this is done, you essentially have an open differential now. This is were you weld your gears. The advantage here is that you have 4 of them to weld instead of the 2 that are normally in the open diffs. This will obviously be stronger.

 

The only problem I see with this idea, is that now you are torquing on the input shafts in the opposite direction from which they are used to being torqued. That could lead to premature failure. But those are easy to replace.

 

What do you guys think? Of course this would not be the best idea for street use but....

[SATAN]

Ok, Went ahead and punched out the center washer in the viscous coupling. This was supposed to allow me to be able to slide the longer input shaft all the way through the viscous coupling, eliminating it from spinning all together. Well things didn't work out like I was hoping and here is why.

 

In this first pic you can see the area in which I am measuring. Take note of how big that area is on the longer shaft in the second pic.

 

Here you can see that part is longer. About 7mm longer. That ledge there hits the bearing and will not allow it to slid in all the way. If I wanted to slide it in all the way, I would have to have that part milled back about 7mm. But even then, there is a chance that the shafts splines would bottom out on the splines in the viscous coupling. I would have to go and extend those as well. Way to much work involved.

 

 

 

So, I decided to stick with my first idea of drilling the splined section of the viscous coupling where it meets the race for the pinion gears. The two sections will share a hole. The hole will then have a drill bit, or some other hardened steel shaft slid into it, and tack welded into place to keep it from coming out. I dont want to fully weld the piece in there because that will change the heat strength of the bit that I slide in.

 

I originally did not want to do this because I thought it would be to weak. I have since thought about it further and decided that it only has to hold the wheels together, it doesn't have to hold massive amounts of torque. The input shafts hold the torque. So I figure 3 or 4 pins should be PLENTY to keep the viscous coupling from even thinking about moving.

 

Even though nobody really seems to be interested, I will still post up more pics as I get further along here in the next few days. Maybe someone will come along one day and need to know this information.

[SATAN]

Ok, figured out how to make the viscous coupling from the Q45 solid. I had to buy special tungsten carbide drill bits. Cost about $30 for 5 of them. Not TO bad. But I drilled out half of the splined section and half of the spider gear section with a 3/16" diameter hole 9/16" deep. Then I slid a hardened steel pin in the hole and tack welded it in place. This makes it solid. If you install it like this, you will have an open diff. Now is where you need to weld the spider gears in order to have the solid diff. I'll post a picture shortly. Also, the links to my other pics are dead because I shuffled my photo bucket account around so...

 

To drill one hole takes about 7 to 10 minutes. You have to go very slow at a low RPM due to the fact that tungsten carbide is very brittle. Very hard, but very brittle.

 

Here are the pics. They look like they are welded a lot, but keep in mind, it is only a 3/16" pin, and it is only welded on the surface. I didn't weld a lot because I didn't want to mess up the heat treatment in the hardened steel. The tack weld is just to hold the pin in place. One of the holes I drilled slightly to far, and viscous fluid started leaking out. Not like it matters, I dont need it anyways. You can also see the failed attempt on the right, when I tried to use a regular drill bit. Yeah that was dumb.

 

Now all that is left is to weld the spider gears, and install it into the diff.

 

 

here are some other pics that dont show up anymore up top.