Gearbox question #2 - removing/refitting gearboxes

Eric Brough · Post by **Eric Brough** » Fri Jun 29, 2007 5:09 pm

Advice and hints requested on doing a gearbox replacement. Is this something that a reasonably-equipped amateur can do on the driveway with the benefit of axle stands... ? What gotchas are there? What special tools needed? How long does it take? Is the gearbox very heavy? etc...

I've got two K-reg BX19TGD estates. The 'good' one with 12 months MOT, new spheres, good rear arms etc and the 'spares' car. The 'good' car has just dropped something in its diff case big-time. This has left a hole punched out of the top of the bell-housing and a crack at the bottom of the diff case through which all of the gear oil has escaped...

Oh dear... anyone want two BX19 estates? One with; one without sunroof ???

E.

jeremy · Post by **jeremy** » Fri Jun 29, 2007 8:00 pm

You can change the diff housings (and diff) in situ. Many recommend it is removed when changing the box.

Post by **docchevron** » Sat Jun 30, 2007 3:56 am

Yes, you can change the diff housings with the box in situ....BUT..

the box will have smashed the planet gear cage (it's what they do), so the box in its entirety is FUBAR. Throw it in the bin. It's scrap.

The bonus is, your car wont be a turbo so changing the box is actually VERY straightforward and easy to acomplish even for the amatuer mechanic.

I hate Haynes manuals (the book of myths, legends and other well known fairy tales) but the process and description is actually quite good for box removal / refitting.

Yep, a BE3 box is fairly heavy, not THAT heavy, but heavy enough.
Get yourself an engine beam, you can then use it to keep the engine in place, and throw a rope round it to pull the box back up when refitting.

If it's the first time you're doing one, allow yourself a weekend, work slowely and methodically, they aint hard to do.

Once you've done a few you can get it down under three hours.

If you get stuck I'm sure we can cobble together a step by step guise to doing the job (including the bits you wont find in the haynes)

Eric Brough · Post by **Eric Brough** » Sat Jun 30, 2007 2:59 pm

Thanks guys, I am encouraged.

I'm not 100% certain from Haynes as to which gearbox is fitted to the 1992 BX19D models. The blue-coloured PETROL manual says BE3 for BX16 and BX19. The grey-coloured DIESEL ENGINE manual says BE1 for all diesels (though it only covers models up to 1990).

Haynes talks about having a dowel ready to keep the diff side gears from misaligning. Scary stuff, but it sounds like thats only a problem on pre-July1984 boxes - correct?

Is it necessary/advisable to change the driveshaft seals at the same time?

They also talk about using an oil-seal protector when fitting the RH driveshaft. Not sure what form that might take.. any ideas?

Thanx, Eric

jeremy · Post by **jeremy** » Sat Jun 30, 2007 3:36 pm

You will find that there are many different sets of ratios used on BX in similar gearboxes. Some vary with the final drive but other ratios can vary as well. BX 19 and diesels (but not TD) vary between saloons and estates.

One of the major differences was the change over of the reverse position from being next to first and protected by a lift up collar to being behind 5th and not protected at all. This change was made in about 1988. I think this is the difference between BE1 and BE3.

For the avoidance of doubt Turbo-diesel gearboxs are not the same as N/A diesels - the top 3 ratios are different to give longer legged cruising.

cauchoiskev · Post by **cauchoiskev** » Sat Jun 30, 2007 4:35 pm

Having never taken a gearbox off, I'm sure this is a stupid question, but would it not be possible to lift only the gearbox side of the car, put the suspension in the low position, then drop the engine until it is horizontal and roll the 'box off on some kind of improvised trolley ?

Post by **docchevron** » Sat Jun 30, 2007 9:02 pm

cauchoiskev wrote:Having never taken a gearbox off, I'm sure this is a stupid question, but would it not be possible to lift only the gearbox side of the car, put the suspension in the low position, then drop the engine until it is horizontal and roll the 'box off on some kind of improvised trolley ?

Superb thinking, but in short, er, no.
Or at least, not easily, not easily at all.

Eric wrote: Haynes talks about having a dowel ready to keep the diff side gears from misaligning. Scary stuff, but it sounds like thats only a problem on pre-July1984 boxes - correct?

Is it necessary/advisable to change the driveshaft seals at the same time?

They also talk about using an oil-seal protector when fitting the RH driveshaft. Not sure what form that might take.. any ideas?

Don't worry about a dowel, that was early boxes only. Yours will have the better cage that doesn't allow everything to fall apart.

Yes, change the diff seals, they very rarely seal again after you pull a shaft.

The oil seal protector isn't worth a w*nk.
It aint required for anyone other than the most cack handed of useless idiots.
Just be careful when re-fitting the O/S shaft, ie, line it up with the hole before puishing, and it'll be fine.

classic2cv · Post by **classic2cv** » Sat Jun 30, 2007 9:36 pm

give a go

just take your time be careful and when in doubt take a tea break

you and a friend or two could do the whole thing in an afternoon

While you have the box off you could take a look at the clutch

And do two birds with one spanner

You’ll have a huge

when it’s all back together and working

mnde · Post by **mnde** » Mon Jul 02, 2007 9:54 am

Eric - do you fancy a hand? I mean, I've never changed a box before, but I'd be interested in assisting and learning! In return you could help fit my BX with a new accumulator sphere

I'm not free next weekend, but possibly the weekend after - or I could pop over on a sunny evening. I've moved to Walton-on-Thames now btw.

Cheers,

Mark.

Post by **docchevron** » Mon Jul 02, 2007 1:31 pm

mnde wrote: or I could pop over on a sunny evening.

Sometime next century then...

mnde · Post by **mnde** » Mon Jul 02, 2007 1:37 pm

Yes. That's how it seems

Mark

RichardW · Post by **RichardW** » Tue Jul 03, 2007 12:48 pm

Doc wrote:The oil seal protector isn't worth a w*nk.
It aint required for anyone other than the most cack handed of useless idiots.

Brilliant, made my day has that!

Right though, as long as you guide the splines through the centre and don't jag the seal it will be OK.