Roll pin failure in GM F35 transmission

[NormLarson]

I only know of two people who have installed the Quaife Close Ratio 6 Speed Gear Conversion Kit and both are in Atom's. There, of course, may be others.  Mine is one and the other one is Fishkiller about 15 miles from me.  Both of us in the last month have had the roll pin shear on the forward gear lever shaft. That is the one with the big counter weight. Mine broke last night.

This is an issue with the Cobalt guys and so eventually it may fail on all of the Eco Atom's.  I was lucky in that a quick phone call had Fishkiller there and we fixed the issue with the non-threaded area of a grade 10 bolt.  The Cobalt guys are telling me this is a real issue.  You will find, on inspection, that Brammo drilled their own hole into the counter weighted sleeve for the shaft. The actually did it for both sleeves and they physically look bigger than the roll pins.  When I have some time, I want to mic their hole and the shaft hole and see if the Brammo hole is slightly bigger.

My shifting was getting progressively more difficult and "clunky".  That is fixed by the grade 10 bolt!

This is a documentation of a maybe issue as 100% of the six speed Atom's have now had the issue.

[bolus]

pics of the part having problems?

[NormLarson]

Not on me.  I will have to shoot some

[Mr.Woolery]

Yep, I've already had that issue.  I had a problem with the roll pin backing out at Atomfest 2007.  It backed out on my one more time, then finally sheared sometime last year.  I replaced the pin with a slightly modified one (spread it to give it a little more tension) and haven't had a problem since.

I do carry an extra one with me though now, just in case.

[bolus]

Where is this located?  right as the shift cables connect to the transmission?

[positron]

They hold the shift levers to the shafts of the trans. The one in question is the fore/aft shifter motion, the one with the big ole honking counterweight. Once it shearing clean leaving the pieces and left me in neutral mid track and had to ride the tow rope of shame, the last time it was all gone and left me in fourth so at least I made it off under my own power. This time I put safety wire just in case it decided to walk out.

Lots of chatter on using a higher shear material and some thinking you may tear up something inside. I went to the hardware store and bought several and put in my travel kit.

[NormLarson]

[quote="Positron"]
They hold the shift levers to the shafts of the trans. The one in question is the fore/aft shifter motion, the one with the big ole honking counterweight. Once it shearing clean leaving the pieces and left me in neutral mid track and had to ride the tow rope of shame, the last time it was all gone and left me in fourth so at least I made it off under my own power. This time I put safety wire just in case it decided to walk out.

Lots of chatter on using a higher shear material and some thinking you may tear up something inside. I went to the hardware store and bought several and put in my travel kit.
[/quote]

I understand the concern of replacing it with something too strong, but, ultimately you have to push it with the lever.  If it doesn't want to go don't force it.

[positron]

hmm.. that doesn't seem to apply in the heat of battle and spanking porches.. both of mine were at speed during 3-4 shift

[NormLarson]

[quote="Positron"]
hmm.. that doesn't seem to apply in the heat of battle and spanking porches.. both of mine were at speed during 3-4 shift
[/quote]

Point taken ...

[positron]

Now, that's not to say that the shift lever may have a larger allowable bit of travel than the receiving end. Overstroking would likely the culprit .. perhaps with cable stretch over time,  travel restriction adjustment(s) would be in order.. have to ponder than one some more..

I noticed that the A3 had a clutch pedal limiter for a similar problem resolution.

[Heywood-Yablowme]

Do what I did and cut that "honking" counterweight off. Has made my shifting smoother from day one,and much less inertia for the pin to absorb. Did it on my Focus many years ago with the same success.   I have much better feel into gears with less crap being flung back and forth every shift.

[maverick1]

Since this is a potential failure item I thought I would post a pic of the area in question.
Forgive my ignorance, but I had never heard of a roll pin. I found out they are also called slotted spring pins.
For other ignorant souls..
"Slotted Spring Pins
A slotted spring pin is a headless hollow cylindrical tube having a longitudinal slot down the entire length with chamfered or round ends to aid installation.  This type of pin is produced to a controlled outside diameter slightly greater than the hole in which it will be installed.  Compressed as it is installed, the pin applies continuous pressure towards the sides of the hole wall.  The pressure provides tension in a radial manner to prevent loosening created by vibration or shock."
Apparently you need a special roll pin removal tool. Something to add to the Atoms tool box as I would not want to get stranded.
What is the purpose of the larger hole?

[NormLarson]

You need a drift to drive them out.  On some modified cars (mine) it is hard to get the straight line to drive them out.  There is a higher strength roll pin from GM that is available.  I have been trying, not that hard, to get the part number.

Good pic, by the way, I couldn't get anything I had down there to shoot that shot

[maverick1]

Does anyone know the size of the pin in question.
Positron thought it was 3/16" x 1.5 inch, but I measured the diameter and it is 1" long, not sure of the hole size though.

[Mr.Woolery]

I gently tapped mine out with a driver (a small diameter punch) when it was time to replace mine.  I then just took it down to a hardware store and bought an equivalent size rollpin from their hardware section.  It's fairly common hardware.