Third Gear Syncro... Failiure??

[Craig!]

Ever since I got my gearbox back after the box was rebuilt with the diff 3rd gear always seemed to have a little crunch at the high end of the rev range, recentlly it's been getting worse and worse and after today the gear just crunches and snags itself into gear.

So I'm thinking the 2nd to 3rd syncro has failed, anyone else suffered this? Does it do it much harm driving it with it crunching? It's fking typical meant to be going to the 'Ring on the 5th July and was just taking the car for its last run out before going!!

 

[MIkey kc]

Gutted for you....sound like the sycro like you say tho, or could be something they did after rebuilding the gearbox. I wouldnt say i would do that much damage but its not gonna get any better as all the metal will start getting round all the bearings n might damage them!

 

[Craig!]

Well if I'm going to ddrive it on it i'll be giving it fresh oil before I set off, whilst I'm there and when I get back the box will be coming out... All i'm really bothered about is the crunch when shifting down, what is actually crunching?

Is it the syncro mesh or is it damaging teeth? Suppose either way if rebuilt it's get a whole new third gear no doubt.

 

[MIkey kc]

the syncro mesh looks like a couple of small discs with teeth around them. The discs are sat on top of each other, and another cylinder shape discs is wrapped around these discs which is then moved up and down these discs by a selector fork to selector a gear. The crunching is prob down to a broken tooth or somthing along those lines which is stopping it from meshing properly..i.e crunching.

It goes something like that anyway i think..im not clued up on gearbox's at all so someone will prob correct me

Yeah i would just get third gear replaced!

 

[Craig!]

Yeh I'm not too clued up on the internals of the box so thats why I was wondering whether it's the third gear tooth actually crunching or is it inside the syncro, basically just wondering if it's OK to drive on it?

I think I remember Bill having syncro problems just can't remember if he left it til it failed or went and built the box straight away?

 

[MIkey kc]

i reckon it should be fine for abit! you have new oil in ther anyway coz uve had a rebuild so wont do as much damage!

reckon its the sycro itself

 

[Craig!]

Cool, it'll be getting fresh oil before the trip, had nothing but nightmares with the gearbox as it leaks by the drive flange... Only just sorted that problem now hit with another one!

 

[MIkey kc]

must of been made on a friday as they say!

 

[Craig!]

Aye, wouldnt be bothered if it wasnt for the fancy I don't want it to stop the car going to the 'ring!

 

[DPJ]

Craig, does it crunch when you do a 'slow' change?

 

[beattie17]

so it has nothing to do with quickshift then?

 

[pj1985]

Could stick some tru blu oil stabiliser in there with the fresh oil to help it last your trip.

 

[Black TDI Turbo]

The crunching is the gears not slowing down to the same speed when engaging them and the teeth grinding together, this is normally the syncro.

 

[Craig!]

Perfectly fine at low speeds, only now really happens when shifting down.

Craig - Is it the main drive gears teeth that grind or the mesh gears, i'm thinking its the main.

 

[Craig!]

Just been back out in it, going up the box feels fine, coming down the box is OK however every now and again you get a crunch... but it can be avoided!!

If you knock it out of 4th and hover over third when the engine speed comes down enough you can select third without crunching then just release the clutch to bring it back up the rev's.

Will give it a gearbox oil change to see if it improves things. Any idea where you can get Tru Blue in the UK rather sharpish?

 

[h17och]

i got a year warrenty on my box! so if i were you i would just take it ring then if i gets worse just get it done under warrenty when you get back! ive if its totaly fooked wen you get bak it dont mater coz you got warrenty!

how much was your rebuild out of interest?

HoocH

 

[Craig!]

Well its been a good girl today so going to give it some fresh oil and possibly put the old shifter on for the trip (short shifters just highlight problems).