Can you drain a manual gearbox on '91 TGD?

[BXMad]

I had to replace a drive shaft boot for an MOT.
Having always found it easier to remove the shaft and do it on the bench, some gearbox oil was lost.
No problems but I didn't have any 75/80 oil for topping up and used 85/90 as a temporary measure.
Bad idea... as it appears I cannot drain the gearbox in situ. Is this true?
But will 1/2 Litre of 85/90 make much difference?

[RxBX]

I had to replace a drive shaft boot for an MOT.
Having always found it easier to remove the shaft and do it on the bench, some gearbox oil was lost.
No problems but I didn't have any 75/80 oil for topping up and used 85/90 as a temporary measure.
Bad idea... as it appears I cannot drain the gearbox in situ. Is this true?
But will 1/2 Litre of 85/90 make much difference?

Don't put anything else other the 'BV' gearbox fluid (Into a manual G/B) as you'll not be able to make smooth gear changes if you put the heavier 'EP' types in what ever the grades (70/80/90) !

Also it is possible to drain the gearbox via the 'Drain-plug' in situ, read thro' THIS thread

For a fresh 'BV' G/B oil change, the capacity = 1.8 litres, therefore you'll need to purchase 2 litres !



If your near Hemel Hempstead. heres a potential bargain (If one bid secures it) and you can wait a few days for listing to end ?


I hope the /\ is of help to you !

.

[Defender110]

Yep you can, 21mm A/F drain plug.

[citronut]

Yep you can, 21mm A/F drain plug.

whats that one of them there metric imperial drain plugs ,
if so you need a metric adjustable spanner to undo it

regards malcolm

[Tinkley]

What is Imperial? Metric and SI units valid since 1896 in the UK.... Maybe a special Metrinch Malcolm?

Personally I would drain gearbox and refill with Total BV 75-80 if the box has done towards 60k (recommended change prior to 1990) or has not had change for 5+ years. With our outboards down the sailing club it is quite interesting to see the water contamination of gearbox oil each year!. We have them serviced (annually) and I have personally done a few small (up to 10Hp ones) ones. Normal service is engine oil, gearbox oil, impellor (read water pump), plug(s) and maybe clean/strip carb. A few other small things like checking earth connection and anode but basically very similar to a m/c engine except gearbox.

If you google Nielson I think you will find a supplier of Total BV 75-80 OK. Good luck.

[BXMad]

Many thanks for the information. I will drain the oily mixture. Just one thing, I can't see a drain plug!
The only think that seemed to be in the right place was a large plastic cap but I believe this is not a drain plug. Is there a post with a picture showing where the drain plug is?

[mat_fenwick]

Look at the lowest point of the gearbox, on the diff housing by the subframe crossmember and you will see the 21 mm (across flats) drain plug.

[Tinkley]

The drain is where Mat says it is. At the rear of the part circular housing beneath where the drive shafts enter is the drain plug, lying in a transverse plane and angled about 45° from horizontal.

If it is a BE3 gearbox the fill is at the end of the gearbox (near side) and is a 19mm pretty shallow custom bolt. Mine was as Mr Stinkwheel might say 'flippin' tight to undo. Why the hell you need so much pressure on a fill nut with soft washer I don't know. Anyway be very careful to get a good socket well planted on the nut as it would be easy to burr the hex head. the drain plug is more robust. N/s fr wheel must come off for access. The plastic plugs you can see on the gearbox housing are for a later cross fork clutch release mechanism, you should not need to touch them.
If you are wondering where the fill is there is a thread on here about it (Haynes shows it too) and you fill it through a funnel and pipe (at least I did) until it reaches the level of the hole ie drips out. That's your 1.8ltr.

Preferably after replacing the drain plug.....

If you are careful removing the drive shaft(s) and replacing you can get away without changing the oil seal(s) but they are pretty easy to hoick out and do if necessary. It can be a little fiddly with the drive shaft getting it all aligned as it goes back but not too bad.

[Defender110]

Yep you can, 21mm A/F drain plug.

whats that one of them there metric imperial drain plugs ,
if so you need a metric adjustable spanner to undo it

regards malcolm

As quoted by Mat, A/F actually refers to 'Across the Flats' rather than an imperial measurement as you have inferred my dear chap, an imperial size would have been 13/16" A/F where the actual size is 21mm A/F.

[Vantman]

A have always understood that AF refers to American Fine!

[citronut]

A have always understood that AF refers to American Fine!

i agree with this / \

but obviously Defender110 was using it as an abbreviation of across the flats

regards malcolm

[Defender110]

A have always understood that AF refers to American Fine!

i agree with this / \

but obviously Defender110 was using it as an abbreviation of across the flats

regards malcolm

So you couldn't use imperial AF Spanners to undo Whitworth, BSP, UNF,UNC bolts etc.

Defender is using the correct terminology for spanner sizes.

[Way2go]

A have always understood that AF refers to American Fine!

i agree with this / \

but obviously Defender110 was using it as an abbreviation of across the flats

regards malcolm

I'm not sure that AF was ever classed as part of the imperial system anyway despite the fractions. Surely this classification was reserved for BSF, BSW and the smaller BA series etc? After all, there is no way you can call an American gallon an Imperial measurement

Sad to say, these Brit spanners/sockets still live on as part my tool kit despite now being called upon once in a blue moon.

[Defender110]

http://www.baconsdozen.co.uk/tools/conv ... charts.htm" onclick="window.open(this.href);return false;

[Way2go]

A useful cross reference. Perhaps the old spanners could be given greater use.