Synchro getting weak in 3rd... could it be just the oil?

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CBA
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Synchro getting weak in 3rd... could it be just the oil?

Post by CBA » 11 Apr 2010 12:30 pm

Hello. Having a bit of a notchy/snatchy 3rd gear, cluth right down, 2nd to 3rd, I feel the cogs mesh together roughly, the synchro can be felt kindof whining a little, like its struggling to spin/slow the cog, it does work, but it's slow, you have to be gentle with the change and let the revs go down to nearly the right speed of third gear... rest of box seems fine- it seems to come and go, worse with a cold box, seems to get better after 10 minutes, but at the end of a long drive the notchy 3rd comes back...
Upshift into third is notchy and theres a snatch/clash of gears, though downshifts are good, you can shift down quite harshly and the gear slots in smoothly...

Does 3rd gerar synchro fail first when the oil is low/thin/old?

Guess I should change the oil in the box but I was just wondering if anyone else has had this problem and what they did to sort it.

CBA
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Re: Synchro getting weak in 3rd... could it be just the oil?

Post by CBA » 15 Apr 2010 11:56 pm

More info on this...

Seems to have good and bad days, the hard selection pops out of nowhere, I'm thinking I have some dirt/sludge/mingingness in there, keeps blocking the oilways...

Can I use engine flush in the box, anything I can put in there to dissolve grime - I know it's totally wrong to have inferior (flush diluted) oil in the box and drive, but for it to work I'd have to change up and down through all the gears to flush out the synchros... What can I do short of stripping it and cleaning manually...

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Speedy88
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Re: Synchro getting weak in 3rd... could it be just the oil?

Post by Speedy88 » 16 Apr 2010 12:19 am

Just sounds like your synchros are fubar m8, nothing short of a new box or a refurb will fix it. You could try new oil and just catch it as it comes out if it doesn't work (that way you've not wasted all that oil).
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CBA
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Re: Synchro getting weak in 3rd... could it be just the oil?

Post by CBA » 22 Apr 2010 01:57 am

Well, I'm thinking of jackng the back end off the floor and putting a pint of "some solvent" in the box, spin it up, flush the bugger out, drain it, refill it and cross my fingers... she only has 59923 miles, I have an original spare tyre (barely legal) that pretty much proves it, most parts are original, waterpump, fuel pump, gaskets, blah blah...

Dendorssers
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Re: Synchro getting weak in 3rd... could it be just the oil?

Post by Dendorssers » 22 Apr 2010 10:04 am

I have a similar problem, although mine is getting it in first gear!
When I first got the car, the current owner drove it from time to time as a transport vehicle for junk... So shifting was a true hell! Every gear up to 4th was hard, but after driving it a few hundred km, it got better. Now all that is left is a rotten shift from 2th to first gear! I really have to feel when the gears are in line and then i have about a 50% chance of getting a good shift... Else, its like brushing teeth!

I hope its over with an oil change, but as I read these post I'm starting to fear there is a much greater problem! I sure don't hope so, cause i don't really have time to look for a better 5 speed gearbox. Mine has only 78k on the clock, I feel that is way to soon to change it!

I have seen that my gearbox is sweating a bit (more then a bit honestly), how can is solve that? Removing the gearbox and put some new seals and gaskets in?

CBA
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Re: Synchro getting weak in 3rd... could it be just the oil?

Post by CBA » 22 Apr 2010 10:00 pm

theres a few "gasket renovator" additives you can put in the oil, never heard them doing damage and if the leak/weeping isnt too bad they usually work, lasts about 1-2 years. follow instructions on the tin to the letter though.

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