Rotational clunk noise with swing arm and superdiff

[nlorntson]

Hi All.

I inherited a project from a friend who stalled out getting the car back together and running.

10ish years ago he completely disassembled a complete, running 1968 stock beetle, sent the body off to be painted and he upgraded the chassis to add front disc brakes, he bought a swing arm transmission with what appears to be a super diff (maybe from Rancho? He can't remember), and he added a dual webber 2110 engine.

I received the project with the body still off and the front end and pan completed The transmission was not installed and had not yet had the axle shafts installed.

I installed the stock axles with new fulcrum plates on each side, and for the super diff, it also got the two snap rings to eliminate the in and out play. The side covers were installed with the proper number of paper shims to gain appropriate up and down motion of the axles and tubes. I've reassembled several stock transmissions but never have ventured into the modified stuff.

At this point I have installed the transmission and engine onto the chassis. Here's where I'm questioning if something was missed.

If I jack up the whole rear end so the wheels turn freely and put the transmission in neutral, I can rotate the wheels forward or backwards and it is smooth with little effort as expected. Quickly rocking/rotating the wheel back and forth I hear a clunk.

If I move the shift lever to any gear and rotate/rock the wheels I get a distinct clunk before the differential engages enough to make the opposite wheel turn in the opposite direction. I took this video to demonstrate.

I'm not familiar with anything other than a stock transmission so I don't know if this is normal behavior or something is missing or what might be wrong. Since this was a complete replacement transmission from a builder (Rancho likely?) and all that was needed was to add the axles, fulcrums, side plates and tubes, I don't believe there is likely anything wrong with the bulk of the transmission.

Any idea what if anything could be going on here?

https://youtube.com/shorts/TI9FfLgsAsI?f

[nlorntson]

Any ideas here?

[mcmscott]

Fulcrum plate has dropped
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68 Ghia
67 T-1
65 Notch
02 Mexican beetle
74 Thing
15 Long travel rail
07 Nomad
05 f-250

[RCP Phx]

Fulcrum plate can't drop as it has no where to go, sounds more like the pinion/ring gear isn't set up properly!

[toxicavenger70]

[richierich]

[nlorntson]

Are the fulcrum plates for a stock axle and a superdif just the normal fulcrum plates or are they somehow specific to the superdif application?

[RCP Phx]

[57BLITZ]

[modok]

If you want us to go out and clunk our tires it's going to be very subjective. Would recommend instead measure the amount of backlash at a distance.

[mcmscott]

[nlorntson]

OK. I'm back to working on this transaxle.

Pulled the engine and transmission out of the car, and disassembled the left side of the transmission and removed the axle tube.

The fulcrum plates are there and perfectly in place.

The link is a short vid that shows the plates in the sidegear, the in and out movement of the axle spade in the sidegear, and the rotational free-play that is the clunk I was questioning.

My understanding is that the builder Rancho (?) shipped this transmission ready to install the stock sidegear, fulcrum plates, spacer, snap rings, etc. so I'm not confident that something deeper inside is amiss.

Yes, I did have to install the extra snap ring on the left side

I'm mostly wondering if the amount of rotational free play is expected. I know the in-and out free play of the shaft is expected.


Link

[niels_kristiansen]

Hi did you find the answer?