5 Speed Box: Whirring in 5th after Redline oil change

[JonB]

I dunno, what?

(thinks for a moment..)

Yeah, you have a gearbox leak and you filled it until it overflowed out of the filler hole.

So Page 51 of the Workshop Manual's Gearbox section has the juice:

12. Replace the drain plug. Through the top of the gearbox add 3 pints (1.7 litres; 3.6 US pints) of SAE 80 EP oil. Replace filler/level plug (A, fig. 43).

See paragraph 12. Sorry if the orientation is wrong!

As I said, because it's in the body of the manual's text, it's easy to miss. And who reads manuals these days, anyway?

[vincereynard]

To be fair (although I don't see why I should) it is just called a FILLER hole.

Should have known going by the organisation of the contents page.

Body / Suspensions / Engine Gbox / Hubs Wheels / etc etc then clutch / final drive / exhaust at the end.

Lotus Logic or the author smoking something?

[JonB]

Definitely been smoking parsley.

It?s probably because the 5 speed came out after the manual was first written. So they produced an insert to be clipped in after the 4 speed section, without updating the Technical Specification section. Lazy swine.

Lesson learned: read the whole section before starting work. I sure wish I?d done so! Cuz if I had, my gearbox and chassis wouldn?t be dripping with Redline! Now I have to work out how to clean it without removing the box again.

So I suppose you?ll be draining / refilling yours sometime soon?

[alan.barker]

Hi JonB,
well i think thanks to you we have all learned something
cheers
Alan

[JonB]

I dunno, Alan. Do you all have leaky 5 speed boxes?

[vincereynard]

Hi JonB,
well i think thanks to you we have all learned something
Alan

Lotus did not have the sense to make a filler plug also the level plug?

If the oil is drained how much does one allow for oil trapped inside. I.E. not
completely filling from dry?

[nmauduit]

Hi JonB,
well i think thanks to you we have all learned something
Alan

Lotus did not have the sense to make a filler plug also the level plug?

If the oil is drained how much does one allow for oil trapped inside. I.E. not
completely filling from dry?

The 5 speed gearbox not being a Lotus development (rather derived from Austin Maxi I understand), I'm not sure to what extent a redesign of the filler plug was fitting the budget... and it does allow to fill the gearbox: this is not the specificity that bothers me most.

[mbell]

The 5 speed gearbox not being a Lotus development (rather derived from Austin Maxi I understand), I'm not sure to what extent a redesign of the filler plug was fitting the budget... and it does allow to fill the gearbox: this is not the specificity that bothers me most.

The gearset/shafts are Maxi but the case is a Lotus design. So they had full control over drain/filler plug location.

I've been meaning to check the shelf in my garage to see how much Redline MTL is left in my bottle. I filled mine from pretty dry (box out and messed around with but not stripped) using two 1qt bottles, so max of ~1.9L. My memory is that it took a bit more than expected but flowed out of the filler plug before I ran out of fluid, but not 100%.

Either case I would have thought it hard to significantly over fill the box.

P.S. I do have slight lean from my box when used which I put down to lack of a breather.

[ericbushby]

This is usually when we would expect Rohan to join in and explain it all clearly.
However he is in Melbourne and may well be affected by the fires there.
I do hope he is OK and not in too much trouble. Best wishes Rohan.
Eric in Burnley

[rgh0]

Hi Eric
Thank you for your thoughts and fortunately the fires so far are well away from where I live in Melbourne but the smoke is something I could do without. The fires are certainly bad and have affected many small towns to the East of Melbourne but not as catastrophic as some on social and other media have conveyed. Every 20 to 40 years or so going back for the last 200 years of recorded history in Australia there have been major bush fires in times of drought in South East Australia. Despite a hugely increasing population in the high fire risk regions over those years fortunately fewer people are being killed due to better communications and emergency management practices. With global climate change, droughts and bush fires may become more common here, but only time will tell on that, as you need about a hundred years of data to really tell.

Getting back to 5 speed boxes -- I have always filled to the level of the fill plug and yes it takes a bit more than the 1.7 litres specified in the manual. I have never had any leakage issues with my original 5 speed box either before or after a major rebuild I did around 50,000 miles ago. I have also never fitted a breather, the gear lever system probably does enough venting. A spare 5 speed box I have, has a leak through the reversing light switch which sits below the oil level at the rear of a 5 speed rather than high up and out of the way off oil as on a 4 speed. The plastic insulation around the wiring where it comes out of the switch does not appear to be oil tight, I must try a new switch when I find time to find one.

cheers
Rohan

[ericbushby]

HI Rohan,
Thanks for letting us know you are OK,
I have not got a 5 speed box on my car so I must not say much, except that I noticed in the section of the manual illustrated above, the plug is called a filler/level plug. Is this a mistake ?
Eric in Burnley
1967 S3SE DHC

[JonB]

Do bear in mind that I am mostly only guessing as to cause. It?s difficult to know exactly where a leak originated when the oil gets sprayed everywhere by the wind. I definitely overfilled the box with Redline and I think this contributed to leakage, but yesterday when I was removing the Cortina stick for a bit of straightening work, I discovered that oil appeared to have been coming out of the breather bolt I?d installed; the ribbed bit where the bolt is screwed into the case was flooded. So I?ve swapped it for a normal bolt and will see if that cures it.

[alan.barker]

Hi JonB,
it looks like you have found the problem that the Breather Mod is not needed. Also it was directly above the Gearing flinging oil onto the Breather.
Maybe if Lotus considered a Breather was need it would have been fitted in a different position or also fitted a Deflector.
Some owners when they blank off the Fuel Pump hole fit a Deflector. Also some fit a Deflector under the Oil Filler Cap on the Cam Cover.
I hope you can clean up all the Oil everywhere or when you drive your +2 people will think it's a Chip Van driving by Pity the Oil isn't Castrol "R", love the smell (i was a Rocker with a Triumph)
Alan

[JonB]

Actually it?s not directly above the gear train. There?s a sort of shelf under the gear selector that ought to protect it from flung oil. It?s in the same place recommended in the 5 speed improvement document and VinceReynard has it there too. Still, YMMV as they say.

I?ve put the Cortina stick back in, straightened, and gone for a blast. Very happy with it now. Shift is still notchy going into 1st and 2nd but I will probably reinstate the Redline as long as the leak is cured. Will see tomorrow after it?s had time to drip (or not) on the garage floor.

Speaking of leaks, torquing up the timing chest nuts seems to have improved the engine leak by quite a margin. Much less oil on the floor this morning after yesterday?s test runs.

Getting there.... slowly!

[alan.barker]

The next time i remove the Engine on my Sprint i will make Gaskets like Brian Buckland for the front Timing Chest and Sandwich Plate. After having all machined surfaces lapped flat
Alan