UN1 shifting problems

[Mike]

I am using a UN1-13 in a project which we just got on road. Using a Toyota cable shifter, we are having a terrible time with the shifting gates getting out of alignment and the shifting locking up. I've had the rear case off three times now.
Any suggestions on how to improve on this? I don't have reverse locked out yet but will do that today.
Mike

 

[Keith Stafford]

Hi Mike

Sorry I can be of no help, I am finishing off a '40 with a UN1013 box, I would be interested to see some pix of your cable set-up as I am considering a cable system.


Keith

 

[Ian Anderson]

I had a problem a long time back where, even though the arm that took the motion from my rod shift was toght as hell on the pinch bolt, it was actually managing to move on the shaft coming out of the UN1.

At one stage I ended up with reverse. Second and forth and another first, third and fifth. Then sometimes no fifth or reverse.

I took the arm off the shaft and ground a flat onto it for the locking bolt to hold on and it made a huge difference.

Perhaps you are likewise getting "slippage"

Ian

 

[Mike]

Keith,
Here are some pics of the cable fittings I fabbed.

Ian,
Good suggestion. Thanks.
Today I fabbed a reverse lockout which seemed to help on this afternoons drive but will implement your suggestion if the problem persists.

Mike

 

[Randy V]

Mike,

You should have someone watch the cable housings themselves while you are running the shifter through its ranges.. If there is any movement of the cable housings between the shifter quadrant and the transmission, that will be a loss of movement at the cable ends. IE, the cable housings themselves need to be restrained from all movement no matter how slight.

 

[Keith Stafford]

My car is not presently running and I am doubtful if all the gears are being selected correctly. SO,.....I'm setting up a steady tripod above the gearbox, marking the linkages and joints with a few white crosses and lines, then taking a photo of the links and joints in each gear position, as well as the various 'left-right' positions of the gear lever (the crossbar of the H if you like) prior to pushing the gear lever fwd or back to select the individual gears.

There seems to be a lot of slop in the system, so I think presently I can very easily mis-select.

K

 

[Bill Musarra]

Mike and Keith,
Rather than set up a still camera, I would suggest a video of the shifter in action. The final resting place of the mechanism may be in the right place but how it got there may not.
Mike, the only thing that I can suggest is the way the cables and hardware are mounted. You have a large torque force on the bolt that is mounted to the side of the hardware. This can lead to a loose or broken(worn at worst) bolt. This will put slop iinto the mechanism, and is what I found in my setup on the 930. Bolts were comming loose or couldn't be tightened enough. It forces a wear in the bolt hole. If you set it up like a yoke, you move the force to a direct push pull arrangement with the force on the bolt in the middle. This allows you to use nylocks without having to over tighten, just snug up. It just has to hold it in place. I modified the rod ends on mine to get that arrangement. It can work either way, griping the rod end or the hardware.

Bill

 

[Stephane Goria]

Mike,

Few things :

1st : Where did you get your gearbox. Your rear cover is the one used in the very first versions of the UN1 gearboxes and no versions of the UN1-13 went with this rear cover. There is no oiling of the 5th gear assembly, so for sure you will break. I strongly recommend you to replace your rear cover to the standard one.

2nd : Your setting, with the UN1, will inevitably drive to bad shifting. Unfortunately, there is some OEM clearances between the finger and the arm helping the finger to move laterally, so because you act on 2 different parts wich have some clearances, it is a very bad seeting. The only way to restore something acceptable is to have actions only on the main arm, the one which hold the finger. You can have a look at a lotus setting and replicate it....even if it is still not perfect but far better than this 2 ways.
If you want to keep your existing setting, I would recommend to shorten the arms, with this length + OEM clearances, you are making exponential mistaken dispalcements....

3rd : Check the tips of your links (inside the gearbox, just removing the rear cover, most of the time, they are worn. The standard (OEM) is to have them perfectly squared, no V shapes

Best

Stephane

 

[Mike]

Stephane,
I bought my UN1 from a German TA rebuilder. He didn't know much about it and only
had it because it was included in a bunch of Por, Audi and VW cores that he had purchased.
Where could I get the proper back cover? I bought a Quafe LSD for Kevin at GTO so maybe he has one.
Thanks for everyones input.
Mike

 

[Stephane Goria]

Hi Mike,

If Kevin doesn't, I have almost 15 un1 dismantled in my warehouse, so no probs to sort one out.

Best

 

[Keith Stafford]

Hi Bill, yes I may have to develop (out-of-date pun intended) from stills to movies. I was hoping to snap the positions at each 'transition' point, thus being able to see the path from A to B as it were, indeed I may have to try to synchronise images of the the stick movement and the gearbox lever, oh Lord, this just gets more and more complicated, part of the enjoyment I believe.

K