I think i've broken my gearbox :(

[speedy king]

Pleeease anyone mechanically minded seeing as im a white elephant when it comes to these things...

I've got a 1.8 16v Astra Coupe and last night when accelerating away rather hard i put it in to 2nd gear and crunched it badly (how great does this make me sound..) anyway, i tried putting it in again and it just made noise, no gear, just revs, i put it in to 3rd and all my other gears work 1st, 3rd, 4th, 5th and reverse, it is noisey though, sounds like how a mud flap dragging off your car on the road would.

I've been told i may have just knocked the aligning out, or the arm might have broken? This is where i'm confused, is there just the one selection arm? in which case surely i would have no gears?? Or is there one on each gear?

More importantly is it time to get looking for another gear box? :(

Thanks in advance,

James

[MrJan]

Try and see if there is a Astra forum. Far better to get advice off people that actually own the car, at least that's what I do when I'm after some info.

[Easy Drifter]

Probably fixable without a complete new box but the more you drive the worse itwill be. There are almost certainly pieces of metal floating around in the box and will get into other things.
Beyond that I cannot help.

[Kneeslider]

Hey Speedy,

Looks like a gearbox out job at the very least I'm afraid.

It's normally quite hard to break a gearbox, but that would do it. Don't forget that breaking 1st or 2nd gear is easier to do than breaking the higher gears because the torque from the engine is multiplied up more.

At the very least you have broken a synchro ring (the bit which speeds up each gear to enable it to mesh when you change) but I think that a cog has probably let go. Any bits which you have newly liberated will find their way to the bottom of the box, and then be transported about in the oil to wreak havoc with the rest of the gearbox.

Often gearboxes on modern cars are sealed for life, and there are no parts available, so your best bet is going to be to try to get hold of a used gearbox from a car breaker, these sometimes come with a warranty.

Don't forget that you can drive very quickly indeed without putting any strain on a gearbox by being careful to match the revs, your clutch will last longer too. All the transmission components tend to be expensive in labour to maintain. Don't rush a change, forcing a gear through won't make it change any faster, if you want a faster change, then you need a racing 'dog' box or a constant mesh type transmission you get in motorcycles, which is the basis for most 'flappy paddle' semi auto technology.

When you get driving again, try to change gears without crunching WITHOUT using the clutch, it can be done, it just takes a little mechanical sympathy, up the box is easy, but down the box really takes practice!

I had my TR6 gearbox rebuilt last year, and it cost £330, but I removed and installed it myself, I would have rebuilt the box too, but didn't have the space because my garage is full of motorbike bits! The gearbox had done 93k miles, was 33 years old, and had a crunchy change going from 4th to 3rd, but didn't crunch when you timed it exactly right, it turned out to have worn synchro rings.

[MrJan]

I've found that on the few occassions I've tried clutchless changing that a blip of the throttle helps (sort of like you would when double de-clutching).

My old man had a gearbox rebuilt when he lost reverse gear. If he'd taken it to Honda then it would likely have been an expensive new gearbox but the bloke he took it to is fantastic and had the whole thing apart to fix the problem.

[Daniel]

New gearbox. Probably the cheapest and most reliable solution in the long run.

[speedy king]

I've decided on a re-furbed box to be fitted, bite the dust and stump the cash time :( I've been told to change the clutch too though, is this necessary? Just a case of finding a garage that have a waiting list of less than two weeks around here :O :(

[Daniel]

I've decided on a re-furbed box to be fitted, bite the dust and stump the cash time :( I've been told to change the clutch too though, is this necessary? Just a case of finding a garage that have a waiting list of less than two weeks around here :O :(
Depends how much the clutch costs and how much they'd charge in labour to fit a new clutch if it goes in the future. You could always get the mechanic to take the box off and advise whether or not the clutch is worn or not. Sometimes when you're having one part changed it makes sense to have other bits done as a precaution ie if you have your timing belt done then if it's not too expensive it's a good idea to have the water pump done too.

[Kneeslider]

If you ever have the gearbox out of a car, then always replace the cover plate, the driven plate and the thrust release bearing. It's a false economy not to. The parts cost probably only 1/4 of the total cost of changing a clutch, and since you are going to have the gearbox out anyway, then 3/4 of the cost of the clutch change is for free.

If you replace everything, then you know that under normal circumstances, you are going to get another 50k miles (at the very least) out of the car without having to do anything again to that area of the car.

My Boxster has 84k miles up, and is still on the original clutch. I am not looking forward to the bill which replacing that would attract!