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MG MGA - 1st gear grinding

Well, I just got back my MGA from having the clutch change, and WOOOW I love the way it drives now, and love how you can run it hard (despite the limited power).

Now as I said the mechanic changed the clutch, release bearing and pressure plate. I saw the old one any it was destroyed from having run with oil on it (coming from a leak in the gearbox).

Here is my question;

I have realised since this work on the engine, that sometimes (not always) when I shift into 1st gear the gear grind slightly as it goes in even if I am at a complete stop. Now if I shift into second and then into 1st (as someone suggested) it never grinds at all.

It seems like if I come to a light an suddenly stop completely and then I shift into first, that is when it grinds. Is it possible that the layshaft is still turning at that point so when I engage 1st gear that stops the layshaft abruptly and so it grinds? I am not very knowledgeable about gearboxes so this could be bo**cks...

Is this kind of normal? Does the slave cylinder need adjusting (maybe clutch not decoupling completely?)?
Does a new clutch need 'breaking in' until it runs smooth?
Should I just take it back to the garage an get him re-check everything?

It doesn't bother me too much but I don't want to grind the teeth of the gears if I could help it...

G Ramos

Do you know what a syncro is?
Do you know that these transmissions have 3 syncros.
They are in 2nd 3rd and 4th gears. 1st gear has square cut gears and has no syncro. It is designed to only be put into 1st gear while stopped.
R J Brown

I always pull the shifter towards 2nd before going into 1st gear. Otherwise it sometimes grinds a little. Always has, probably always will.


Ed Bell

I am aware that the first gear is not synchro.
As I said I was shifting into 1st when FULLY stopped and it still was grinding slightly. That is why I was wondering.
Ed's comment reassures me.
By the way I hope you know how to put all the bits of the gearbox together you have on that pic. ;O
G Ramos

When you step on the clutch, the clutch plate and the front half of the gearbox innards are turning; a lot of inertia and it takes a finite time to stop. The synchro - any synchro - acts as a brake, and since you don't have one on first, use second. Becomes second nature after a while. Also helps to pause a second or two after clutch depress before putting it in first/rev. New clutches may drag just enough to be annoying until the nubblies on new plates wear in.

FRM
Fletcher R Millmore

I think I was feeling some of the inertia.
Ok, thanks so I see there is nothing to worry about...
Thanks Fletcher.
G Ramos

Glad you are enjoying driving your MGA Gonzalo, I have only managed to drive mine twice since November because the weather has been so bad.
I always used to slip the gear lever into 2nd gear before I selected 1st. This always seemed to line up the gear wheels on first gear and make it quite easy to select. Otherwise, 8 times out of 10, 1st gear would not select.
Also I would never select 1st when the car is in motion, it possible to select when the car is in moving but you will find that the gearbox makes horrible grinding crunch when you try to change down from 2nd.
So dont try to change down into 1st whilst moving, only from a standing start.

You can avoid lots of un-necessary wear and tear if you use the gearbox as above and also avoid embarrassment.
The habit of selecting 2nd before 1st is so ingrained that I still do it even though I now have a 5 speed all synchro gearbox fitted to my car.
Best wishes
Colyn
(apologies if you already new this stuff!)
Colyn Firth

I tried to update this but ran out of time.
I forgot to add that if your gears are still grinding slightly when you select a gear even when your clutch pedal is fully depressed, then your clutch is dragging a little. If this doesnt improve after driving a few miles then I would recommend you return it to your mechanic to have it fixed.
Colyn
Colyn Firth

Funny, I don't even think about trying to find 1st gear anymore. It is just natural. I have tried shifting to 2nd and then to 1st, but sometimes the gears didn't align just right and I had to let the clutch out in neutral to get things spinning again. Even then I don't always find 1st. I have gotten a natural rhythm and just go from neutral to 1st. I wait some amount of time, maybe to the count of 3 (not sure it just becomes natural) and always find first gear just as things stop spinning in the transmission. Or maybe I sub-consiously hear something slowing down, I'm not sure. It becomes a learned thing.

Gonzalo, if I understand what you said above,

"It seems like if I come to a light an suddenly stop completely and then I shift into first, that is when it grinds"

you find first as you stop and then sit in 1st gear waiting for the light to turn. With your foot on the clutch waiting for the light to turn is not a good practice in the MGA. The throwout bearing is a carbon block and not a roller bearing. By sitting at a light with your foot on the clutch, you will prematurely wear out the throwout bearing. I always sit at a light with the car in neutral and foot off the clutch. Then as the opposite light turn yellow, I go into 1st gear and am ready for my light to turn green.
Chuck Schaefer

Congratulations Gonzalo,

Sounds like it's beginning to drive like it should!
Neil McGurk

Thanks guys for the tips!
Indeed I will try not to press the clutch in if not necessary. The old throwout bearing had like .5mm left of carbon when it was taken out.

My year's resolution will be to treat the clutch an gearbox properly like they deserve... ; )

G Ramos

This thread was discussed on 16/03/2010

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