Shift Linkage on Three Wheel VW Trikes

[george4888]

I recently came across a homemake VW trike and the owner was complaining about it not going into third and fourth... Usually,,,this is the same problems that one has on the Bug,,,with a bad nylon bushing inside the tunnel or a bad coupler, but both of those had been replaced. I took the shift rod linkage off the transmission and went thru the gears and the transmission works good. But,,,finally I realized that whomever built this homemade frame placed the shift rod at about a 30 degree angle,,upward by the seat, and that caused the shift rod to work good for only first and second,,as the shift rod that sticks out of the transmission only has to move forward and backwards, to grab those gears..

Trying to turn the shift rod to "grab" third or fourth gear would not work due to the angle of the shift rod binding on the cross-threaded rod that goes thru the coupler. Since it would be very hard, without an addn. bearing support to run the shift rod thru with a universal joint added into the shift system,,,,I fixed the binding problem by simply taking off the VW factory shift rod and on the hole which the threaded rod goes thru , which connects the coupler with the shift rod,,,,used a 3/8 inch drill bit and enlongated that hole in the end of the shift rod,, only moving the drill back and forth to make the hole larger, following the line of the rod. In other words,,,place the shift rod in a vise, and looking at the hole where the coupler attaches,,,have the shift rod level, with the hole on the horizontal. So, when you put the drill bit into the hole,,,which basically already is 3/8 inch in diameter, move the drill bit along the line that follows the leveled center line of the shift rod.. Don't round out the hole,,,just make it larger following the shift rod from one end to the other. I think the correct word may be to wallow out that coupler attachment hole,,,but only following the line of the shift rod,,as you have it in the bench vise.

What that does,,,is allow the threaded rod which goes thru the shift rod to move slighly and not bind,,,and this is a problem only if your shift box is located in a postion other than the normal ( which I usually see) straight line box, lined up with the transmission shift rod. I you look at most sandrails with a rear mounted engine,, you will see that the shif box and shift rod is usually on the horizontal and as straight on level as possible.

My point is if your trike was built with the shift rod box mounted where the shift rod makes a downward angle to attach to the transmission,,you will most likely have this same problem. The wallowed out hole does not affect shifting from gear to gear,,,in other words....moving the rod on the transmission in and out to change gears. It only stops the binding, from the turning of the shift rod as you change from 1-2 position to 3-4 position. Also,,,don't forget to use the correct shift plate under your stock shifter or the correct plate that came with your custom shifter.

On the one I was working on,,,someone used the shift plate from the semi-auto bug,,,,which was so,so wrong.

After putting on a stronger shift box and the simply modification to the end of the shift rod hole,,,,now all the gears are found without any problem,,, no "fishing" for them. It shifts just like a stock Bug,,,with all the parts in the proper position... Just sharing this information.

If you are building your own trike,,,I really recommend you place the shift box even on the same line as that of a stock Bug and avoid the above problems. It is all in how you design the frame under the drivers seat. Have fun..... George4888
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