6 replies to this topic

[bazhb]

My 1970 1275gt has always 'crunched' when changing down from 4th to 3rd. Paid for a gearbox rebuild last year which sorted the problem for a couple of hundred miles when the crunch then shifted to 1st to 2nd. Paid for another rebuild this year (it's getting very expensive) but 'mechanic' can't seem to sort problem. Garage has, as I said, rebuilt box, sorted clutch travel and linkage wear and has now sorted gear linkage wear. But, it still crunches when changing from 4th to 3rd. The 'mechanic' has told me that this'll disappear after about 1500 miles but I find this difficult to believe. Would very much appreciate ideas, solutions, opinions as the old finances are rather depleted.

[Guess-Works.com]

Your mechanic is talking pooh to be quite frank.... a CORRECTLY rebuilt box will not crunch unless your clutch is spammed... and even then it'll crunch in all gears, and especially going into reverse...

But... there is one thing which may be causing the problem, and this is that you gears are actually worn out... I'll try and keep this simple.. The things which enable the smooth ( no crunch ) gearchange are called baulk rings, these wear out, and generally when replaced with new ones, everything is ok. But.. these work on a friction surface on the gear, and after a life of use this too has a tendacy to wear, but much slower than the baulks. I have one gear in my stash which this has happened too... and even with a new baulk ring there is not enough friction surface left on the gear to enable a clean gearchange.... and just to rub salt into the wound it's a GT 1st motion.

how much you been stiched for so far if you don't mind me asking ?

Edited by GuessWorks, 21 August 2005 - 11:33 AM.

[bazhb]

Thanks for your reply and confirming my thoughts. To date, ignoring the 1st 'rebuild' last year, I've been relieved of just over a grand. Something else I found peculiar was the garages method of dropping the whole front subframe off of the car. In me youth, before days of stupid working commitments, I always had the lump out of the top as was the quickest route.

[Guess-Works.com]

:nugget: owe !

As for dropping the subframe... if your after the gearbox then yes it is a long way of doing things, because even after dropping the subframe, you still have to remove the engine from it to get the gearbox out..

However, it is possible to drop the gearbox with the engine/subframe still in the car but it's a fiddle.

If you in the market for another box then see my link below :cheese:

[Jammy]

I've just been thinking, do you have to remove the clutch and flywheel to remove the gearbox (if you weren't removing the engine from the car).

[Purple Tom]

yes, you'd still need to remove the transfer gear case to remove the gearbox, as the idler gears are supported in the transfer case.....and to remove the transfer case the flywheel has to come off....bloody Mini's!! :nugget:

[Guess-Works.com]

Seen it done though... !