Problematic shift into first gear when stopped

[hpage66]

Occasionally, perhaps 5% of the time, transmission in my Series 2 refuses to shift into first gear when stopped. Otherwise it's working flawlessly. Any ideas? Thanks!

REgards,

Howard

[Gfhug]

Quite a few of us have experienced a bit of reluctance to select first gear and we tend to select second gear then find it’ll go smoothly into first.
That may help you, though I can’t claim to know why it is reluctant to go into first without this common little trick.
I hope this’ll help you but out of interest do you know when the gearbox was last overhauled?

Geoff

[hpage66]

Thank you for your reply. Tried that. Occasionally works. Other times I simply start in second gear. If one puts a moderate amount of pressure on the shift lever, it works but makes this awful grinding noise as it would if one were to downshift and force it into gear before the syncros spins up.. No documentation regarding the transmission, I would not be surprised if it had never been rebuilt. Maybe time to budget for a rebuild or 5-speed! Thx.

Regards,

Howard

[abowie]

Might be worth an oil change.

Redline MT90 seems to be the popular choice for the all synchro box. You need 1.7l.

[christopher storey]

If you are getting a grinding noise then something is rotating , and this is a sure sign that it is not the gearbox at fault , but that your clutch is not releasing properly. Bleeding and adjustment of the slave cylinder pushrod would be the first thing I would look at

[abowie]

and this is a sure sign that it is not the gearbox at fault

I'm not sure I follow you there. Can you elaborate?

[christopher storey]

Andrew - what I meant was that if there is a grinding noise, then there is rotation, which with the clutch out i.e. pedal fully depressed should not be happening. Given the perennial problems with the slave cylinders, then far and away the most likely cause is air in the cylinder / cylinder failure/maladjustment

Perhaps it would have been more accurate to say " the substantial likelihood is that it is not the gearbox at fault"

[tinworm]

The technical term is 'clutch drag' gents and well you know it - !


regards Barrie

[hpage66]

Thanks, everyone. I ran this by a local British car mechanic, he suggested it could be a defective pilot bearing (pilot bush). Next time it happens I stop the engine and see if it slides into gear. Wonder how it can intermittently fail in this manner, unless perhaps it's completely trashed and the transmission pilot shaft is bouncing around in there..!

Regards,

Howard

[christopher storey]

I think it is very very unlikely to be the pilot bush. In the first place the bush is phosphor bronze, IIRC of the oilite variety , and these last virtually for ever. More compelling is that if the shaft were running eccentrically, then you would virtually certainly have trouble in getting clean gearshifts whilst in motion, because the shaft would cause the driven plate to bind up

In any event, if I may be so bold to advise, look for the easily cured possible problems first , e.g. hydraulics,and eliminate them as a possibility, before going for the difficult ( and expensive ) remedies

[chrisfell]

A question. When it baulks at going into first gear, does it also crunch or grind when selecting reverse?

[hpage66]

Don't recall, will attempt the next time it occurs..

[Joes66]

This sounds very much like a worn synchro on first gear to me
Or as stated it needs an oil change
I've also had this problem with a faulty clutch not fully disengaging
But I would would go for the synchro being the cause
The synchro on first gets a lot of punishment compared to all the others and if the car has had a heavy user at some point its easy to damage it
Putting the gearbox into second first is a clue as it aligns the synchro for you on first
This is a usual thing on gearboxs especially with no synchro on first
Sadly on non synchro on first boxes this usually leads to the synchro and lay gear on second wearing out and sliding out of gear on the down throttle
My thoughts anyways
Joe

[hpage66]

Two more data points. When this issue occurs, indeed shifting into reverse is problematic. When moving the lever very slowly into reverse, can hear a slight grinding noise. Also discovered I can start off in second gear for a brief moment then successfully switch into first.

So I guess the first thing to do is bleed the clutch. Was looking to do it myself but can't fit underneath and don't have any jacks. My normal shop wont touch it, the local British auto repair shop is backed up for a couple of week.

Thanks!

[mgcjag]

As mentioned already bleed the clutch but importantly check the adjustment of the pushrod as per the service manual....Steve

[Joes66]

Now sounds more like the clutch issue after your last 2 points
Joe

[hpage66]

Bled the clutch twice, first with a vacuum bleeder, second using the "drip" method. No change. Dropped it off at the local shop, word is that the clutch slave cylinder is faulty and will be replaced. Place your bets!

[Tony]

I had this problem of difficulty getting into first gear. In particular when the engine was hot. It was simple a case of adjusting the the push rod. Works a treat now.

[mtnjag]

Hope this isn’t redundant, but I don’t think this was covered above.

You bled the clutch but did you adjust the push rod on the slave?

I don’t know which type of slave you actually have vs what you should have but it may not be fully fully released at stop due to the slave push rod. For some reason 1st may grind but second won’t in some situations. Was my condition with early short/spring loaded slave.

Also I suppose someone could have switched the slave type and not the rod.

[hpage66]

Replaced the master and slave cylinder, plus the flexible coupling of the clutch line. Not much better, so...

Removed the engine.. Splined shaft bone dry. Release bearing completely worn out (previously observed).

To his credit, a Jag mechanic I contacted suggested grabbing a can of spray lubricant and lubricate the splined shaft via the release fork opening and inspection hole (series 2 have an inspection hole?).

My machinic didn't wish to pursue this because the release bearing had to be replaced in any case.

$$$ repair for $50 part. He going through the transmission as well, replacing bearings, synchros, etc. plus motor mounts, u-joint bearings, water pump, etc.. Considered a 5 speed but, a) difficult to source, and b) many said stock transmission is awesome, keep it!

That's it!