901 Gearbox help

[Alfie]

Hi all, In an effort to improve the shift quality of my '68 I removed the quick shift kit and fitted a standard version that I have stripped, cleaned and re lubricated. I have also replace the slider bush and fitted a new ball cup. The improvement in shift quality it's great but I am still suffering a couple of issues I would like some advise on:

1. The reason I started looking at the linkage and shifter is that 1st gear has been difficult to engage. It generally deteriorates in quality after about 20 min driving resulting in potentially grinding to find 1st. Reverse gear is fine and can be engaged all the time. Since changing the shift linkage and bushes this is much better but first is still harder to get after 20 mins than when cold. - The car has a new clutch and I have adjusted the cable so that when pressing the pedal by hand I can feel it go over centre at the end of the travel, this results in about 20mm free play at the pedal when not engaged.

2. The second issue is when changing from 2nd to 3rd as I pull on the lever it sort of pops out of gear rather than smoothly disengages - any pointers.

Thanks in advance for any help

Alfie.

[classic]

Alfie,

Get someone to hold the shifter vertically in the 4th and 5th gear plane.

Undo the two 13mm bolts, and see if you can rotate the selector shaft more towards the drivers seating position (LHD).

It sounds to me like you are not quite aligned.

Use a wax pencil or chalk to mark the shaft, so that you're not chasing your tail adjusting it.

[savaden]

Sounds to me like a worn synchro and dog teeth on first gear. The worn synchro because it gets worse as the oil warms up, and the dog teeth because it pops out shifting from first to second.

SV

[Alfie]

Thanks for the responses, I'm pretty sure it's not a linkage issue as initially the change is fine, only as it warms up do I get issues. The popping issue is apparent changing from 2nd to 3rd more so than 1st to second.
I suppose I want to dismiss all easy options before I have to delve deeper...
Tony, I will double check my adjustment but am pretty sure that this it is set correctly
Thanks,
Alfie

[gled49]

I haven't rebuilt a 901 trans that didn't need 1-2-3 syncros, 1-R shifting sleeve, 2-3 shift sleeve and usually 1-2 dog teeth. Sounds like it is rebuild time. The pop out of 2nd when shifting into 3rd sounds like you are not dipping into the clutch enough when you pull the shift lever. Maybe tighten up the clutch adjustment to help disengage clutch. Try that first, for the pop. If grinding, with that adjustment, is not improved it is time for a rebuild. Gled

[Alfie]

Thanks Gled, I suspect that my clutch is not fully releasing when I press the pedal. I have had a new clutch fitted recently, I have also adjusted the cable to reduce the play in the pedal. If I can feel the pedal go light at the end of
it's travel I believe that this means my clutch should be fully engaged? I

[classic]

Correct you should feel the over center feeling (pushing by hand) and adjust the cable so you have 20mm free play at the peddle.

Don't forget to adjust the peddle stop on the board, to prevent straining things.

I had the same condition that you describe, but it didn't change with temp. Slight adjustment of the shifter corrected my issue.

But as others have said, with the change with temp it may be a synchro.

[911s55]

Alfie, I've had similar symptoms in my 902 5 speed. I got a bit of relief for gear changes by switching to Kendall gear oil and slowed my 2nd to 3rd shift a half second or so, letting the synchros catch up. My first and reverse gears are very tight to engage with much less lateral play than 2-5 and it's adjusted properly, but no grinding.

Character, personality, quirky, I guess. Not problematic enough for a teardown though, good luck.

David

[Alfie]

Thanks for the replies, I'm going to have another play this weekend, double check shift linkage and clutch cable. Have a good weekend
Alfie

[classic]

Good luck, and let us know the out come.