Backlash in the Transaxle?

[DoctorDex]

Looks like this guy here probably has a fix:

http://www.3si.org/forum/showthread....96#post4648096

[3Sfever]

My car does not have the clunk you describe, but for some reason this thread caught my attention while researching the drivetrain.

I have no actual experience with the parts you are referring to, but thought of an idea looking at the pictures in this thread. The idea is similar to making flanged pins, but instead of making new pins, how about making the "flanges" as separate parts?

Seems like it would be possible to find some tubing of the correct I.D. and O.D. that it could be pressed onto the pins. (effectively increasing the O.D. of the pins.) To increase the surface area of contact between the pins and the VCU, select tubing with O.D. larger than the width of the slots, then grind flats on the sides to match the shape of the oblong holes.

If tubing is not available in the right size, might be easy to make on a lathe.

Just a thought.

.

[keithmac]

That`s not a bad idea!.

[DoctorDex]

Am about to attempt to fix this problem once and for all.

I'm planning on pulling the tranny case off (with the tranny still in the car) and I'll pull the OS-VCU-Planetary and I'll weld any parts together that have any play. Can anybody see any reason why this won't work?

[keithmac]

I was told to do it properly and get the OS back in again you had to strip the gearbox removed from the car?. If you have a go can you post some pics up as mines bad as well, need to have a look into it but I haven`t got time to pull the trans out.

I think if you weld it propely to give no slack the OS can`t be separated from the VCU?.

[DoctorDex]

Originally Posted by keithmac

I was told to do it properly and get the OS back in again you had to strip the gearbox removed from the car?.

I remember something about this as well. However, you'd think that if you can replace the OS/VCU/planetary with the tranny still in the car, then you should be able to replace the three as a unit.

If this isn't possible, I'm planning on just welding the planetary dowel pins into the VCU. That way I should be able to just tap the planetary assembly onto the vcu-dowel pins.

Originally Posted by keithmac

I think if you weld it propely to give no slack the OS can`t be separated from the VCU?.

I'm only going to do this if there is slack between my OS and VCU.

[DoctorDex]

Just got off the phone with one of the guys at Mark Williams and they told me that if I try and weld anything to the 300m shaft, when the shaft heats up, stress cracks will form and the shaft will snap. So there goes that idea....

With regards to my original idea of welding the dowel pins into the viscous coupler; I'm worried that by welding around the hardened areas of the dowel pin holes it is going to make the hardened steel holes into mild steel holes. With time the holes will eventually pound themselves out again because the metal around the dowel pin holes will be much softer.

The only idea left is just to weld the planetary to the viscous coupler, similar to what phatlard did, by cutting a V groove between the two parts and then welding them together. I am going to look at doing this, probably tomorrow afternoon.

Edit: Revisiting an old idea, I found a company that will custom machine dowel pins that fit into the oblong holes and they would be press fit. The material would be 4340 and it would have a Rockwell hardness of between 35 - 40. Would this be hard enough to prevent wearing away of the dowel pins/outer pinion shaft? For just the basic pins, they gave me a ball park figure of ~ $100.00 CDN (cost would be cheaper if anybody else wants some). If I wanted them to have additional hardening it would obviously cost extra. Can anybody tell me if these will work or not? I don't know enough about the engineering/physics/alchemy of metals...

[maddog]

Originally Posted by DoctorDex

Just got off the phone with one of the guys at Mark Williams and they told me that if I try and weld anything to the 300m shaft, when the shaft heats up, stress cracks will form and the shaft will snap. So there goes that idea....

is there really that much slop between the os and the planetary set? i dont recall ever seeing any. i know my slop is from the dowel pins into the vcu

[DoctorDex]

Originally Posted by maddog

is there really that much slop between the os and the planetary set? i dont recall ever seeing any. i know my slop is from the dowel pins into the vcu

I don't think there is either, unless it gets really worn, but mine is relatively new.

Will keep you guys posted if I can get those dowel pins machined. Anybody interested?

[KORMEX]

Here's a tip for what you're trying to solve :

Remove the the long dowel pins from the planetary by punching them out , install them upside down in the inner satelite gears .

Think about it next time you have it dis-assembled .

Make a write-up about this