William MK2 Cosworth

Hello all,

I have a bit of a problem with my T5 gearbox i would like to run by you before it goes for stripping, in case it is a simple fix

When I try to make a quick change from 3rd to 4th gear, the lever kind of seizes in neutral, and when the engine speed drops to roughly 4000 rpm it goes into gear easily. The box does not crunch any gear, and even if I try to force it, it will not get into gear, nor will it crunch. It just stays stuck in neutral.

If I try to make quick changes at high rpm, but with no load, it goes into any gear with no problem and it is also on the standard lever

I have changed the oil in it for new castrol dextron 3 ATF, it made it a bit better, but no cigar.

Power wise I am currently at 270 horsies at 1.1 bar of a standard engine/turbo set up

Any help appreciated

Thanks
William

nixon_2wd

Worn syncros on gear and slider -> the slider does not engage with syncroring and gear, and feels like hitting a brick wall.

Remember the syncro mechanism consist of three parts; gear, syncroring and slider.

If its crunching its the syncroring that is not able to accellerate / decellerate the gear due to friction surface wear, and the slider and gear collide at different speeds -> worn syncroring.

I think you need to replace the input shaft (4th gear) and syncro sliding hub 3-4 (slider).

William MK2 Cosworth

Thanks for the quick reply,

There is no crunching at all at any gear on upshift or downshift. I also have no whining or gear poping out, so I think it is not related to any bearing, and I hope it does not have any wear on the input shaft, as there are no spares here in Greece.

Is there any possibility that the gear lever/ selector mechanism is to blame?

William

nixon_2wd

Its most likely the syncros.. I can get brand new T5 input shafts, though they are a bit pricey.

William MK2 Cosworth

Cool, I will give you a shout if I can't find anything when i have it stripped

William

nixon_2wd

Look at the dogs (on the gear) and see if they are rounded or damaged. They should be perfectly pointed, like the roof of a house.

This is an example of worn dogs:


They should be like this:

William MK2 Cosworth

I have seen worn syncros before in different gearboxes, but I have not seen the lever stick before.

When I have my box stripped, I will post some reference pictures of the damage I find

William

Toe Knee

iTrader: (2)

Nixon do you fix cossie boxes?!

Sorry to post here but the speedo drive in my box must have moved and don't wanna strip it myself and wondered how much it would cost to fix, feel free to pm

nixon_2wd

Yes, I have been doing them for about 9 years now, but im not in the UK
The speedo drive is a simple fix and shouldnt be expensive. I would of done that for free if you gave me the box

Turbosystems

iTrader: (5)

shift plates and synchro ring
design fault plenty fixed under warranty when new

William MK2 Cosworth

The only other info I have, is that the car I took the engine and box out of, had approximately 75 k miles on it, and when I had the engine rebuilt, it was in mint condition, so the box might have never been opened, if the whole car was not abused

gabbo

Sorry to highjack a thread but im going through the same problem. I have a 2wd sapphire at stage 1 to and my 4th gear i have to go to engage it twice for it to select the gear then with 3rd i can go up the gears like from 2nd to 3rd but cant come down gears like 4th to 3rd or 5th to 3rd.

2 of my mates have got 2wd cosworths and they have a spare T5 between them that 4th gear cant be engaged atall.
We have had a 5th gear puller made to remove 5th gear and stripped this spare box down to find the 3 slipper pads inside the 3rd/4th synchro hub to be worn and the C clips that hold these in were snapped. We have replaced these and rebuild the box. I put this spare box now in my car on sat and i can now select 4th but it sometimes struggles to engage 4th when coming down the gears.

So at the moment its driveable but a newsence to be honnest. So as we have the 5th gear puller i thought id ask people on here their opinions as to whats wrong with my origonal box and also what parts are required.

Also where's the best place to buy good parts for the T5 gearbox. I dont want to put cheap aftermarket parts in my box and them not be up to the job of fixing it.

Thanks Dale

William MK2 Cosworth

Good point, I would like to know where to find parts before I strip mine.

the only set I found was burton's rebuild set, but it doesn't have the selector/ hub type thing that makes the engagement

gabbo

I have found them on ebay but just a bit unsure as to what quality they are?

mark r

Try ttd Motorsport Madrid Spain,he rebuilt my t5 . The rebuild kit cost around 350 euros or try Bara Motorsport


Mark