lotus 5 speed lube

[gjz30075]

So, I've fitted my Lotus box and have driven it about 50 miles and really liking that 5th gear. Shorter 1st gear
is tolerable. What's really not tolerable is the 1 - 2 shift and 3 -2 shift. Nearly impossible to get into
2nd. All others are notchy and takes a deliberate effort to put into gear. The shifting was improving slightly (or I'm
getting used to it) at the end of 50 miles. Yes, the clutch is releasing just fine (pretty sure, anyway). My gearstick is an Alex Black copy of his latest, which is basically the stick on a bush, directly over the stub coming
out of the gearbox, and not a good one but good enough for my test drive. It needs refinement, for sure.

The lube I'm using is Castrol 20W50. I think I've read all there is on the 20W50 vs MTL debate and from
what I'm understanding, the MTL is superior but maybe stick to the 20W50 from break-in. Would this be
correct? Or, go straight to the MTL now?

[nmauduit]

I don't have a wide experience since I have not driven my 5 speed Lotus gearbox all that much (maybe 20 hours, 30 max) but I've gone MTL directly when I got it from overhaul (I don't think there was much "breaking in" to do anyway since the gears were not new for most of them).

My main concern with it so far has been some difficulty to go from 5 to 4, which I have alleviated a bit by adding a washer to relieve the locking spring for the 5th.

[mbell]

I just put redline mtl in mine, shifts are ok but a bit notchy and some times tricky too get 1st and get out of 5th. I also only done a limited amount of driving (500 miles), on what looks like a rebuilt box.

How would you describe the shift?

Can you post a link to the gear stock setup you are using? Have you done any other mods to the box?

[StressCraxx]

I think using 20W50 motor oil in a gearbox is a significant compromise. I don't have a 5 speed, just the humble semi-close four speed, so take my advice with a grain of salt.

Motor oil does not have the film strength or additives needed for gears and rolling element bearings. If I was not satisfied with the gear change, it is inexpensive to try the Redline MTL or a good synthetic 75W90 transmission oil.

I was not happy with the shifting with Redline MTL years ago when I redid my 4 speed box. I went to the Redline 75W90 gear oil and it shifts the way it is supposed to. YMMV

[nmauduit]

I think using 20W50 motor oil in a gearbox is a significant compromise. I don't have a 5 speed, just the humble semi-close four speed, so take my advice with a grain of salt.

Motor oil does not have the film strength or additives needed for gears and rolling element bearings. If I was not satisfied with the gear change, it is inexpensive to try the Redline MTL or a good synthetic 75W90 transmission oil.

I was not happy with the shifting with Redline MTL years ago when I redid my 4 speed box. I went to the Redline 75W90 gear oil and it shifts the way it is supposed to. YMMV

From looking on the web at the time I had to decide I found that MTL was a consensus for Lotus 5 speed (and Jaguar Moss boxes), while MT90 was preferred for Lotus 4 speed (and Jaguar all synchro boxes) ... any opinions on that topic from the forum ?

2 technical aspects I read were about brass protection (from sulfur attack) and adequate synchro friction to synchronize quickly (so let gears be changed smoothly)

https://www.redlineoil.com/product.aspx?pid=45

[gjz30075]

I bought this box as 'rebuilt' from Dave Bean (RIP). He only knew that it was 'rebuilt' from "some guy in England", so our knowledge about this box is a crap shoot.

Scroll down in this thread to see pics of Alex's gear stick. I'm trying to emulate this. It's going off to my
machinist for refinement lotus-gearbox-f37/gearbox-swop-t21414-285.html
The shifting, ie, the stroke and feel, is much like the 4 speed, as Alex mentions, so this is the design I'm
sticking with for now.

Sounds like, however, MTL is the way to go. I'll be changing it today.

Thanks all!

[nmauduit]

regarding the gearbox lever, I've followed the Hollnagel paper suggestion to modify a 4 speed gearbox, which conveniently brings the handle near the original location and not too close from the dash (cf. photo from a previous post lotus-gearbox-f37/lotus-speed-gearbox-and-concentric-clutch-t32719.html?hilit=gearbox#p241555 )

http://images.lotuselan.net/lel/34299/0 ... cation.jpg

I just sourced a new repro lever for that purpose so that I would save my original 4-speed one, cut the weld with a grinder and welded it back on turned 180?, then tapped the 5 speed protruding stick M10 to attach it (possibly after cutting it to length, don't remember or sure now). Would be perfect if the repro rubber bush was not of poor quality (very smooth inside and prone to rubber slipping), manufactured in far east for a usual suspect at the time.

[rgh0]

The original Lotus recommendation is a 80 weight gear oil in both the 4 and 5 speed gear boxes. I use MTL which is a 75w / 80 gear oil specifically designed for manual syncromesh gear boxes and it works well for me in both my 4 speed Elan and 5 speed plus 2. May be redline MT90 which is a 75W/90 manual gearbox oil is better in some boxes depending on their condition. i would start with MTL and try MT90 if not happy. I use MT90 in my Esprit and Landcruiser as a 75W/90 oil is specified for these gear boxes. Currently trying to work through the oils for my sons Golf R32 ( engine, front diff, gear box, transfer case, Haldex rear wet plate clutch unit , rear diff ) - VW make it hard by only quoting VW oil part numbers and not providing any other details on the oil specification to try to get you to buy their overpriced oil.

I would not use motor oil in a gear box anymore than I would use gear box oil in an engine.
I would not use a standard GL5 75w/80 or 75W/90 gear oil either in the gearboxes. Safe that for the diff

Of course all this is just my opinion and what I do in my cars based on 40 plus years of lubrication work on million dollar machinery plus lots of years experience with my various Lotus , Lots of other opinion by lots of people

cheers
Rohan

[gjz30075]

Nmauduit, I have a similar stick, made up by me, needing a bush and already chromed, so nearly ready to
go as 'plan B' .

Rohan, I'd knew you'd chime in with your knowledge and I appreciate it. I had once tried a synthetic
in my 4 speed box and hated it. It felt like there was no lube in the box at all, so I changed it back to
80W-90 regular stuff. I'll be changing to the MTL GL-4 type today. We currently have Hurricane Irma
passing through so it'll be awhile before I can test this all out .

Thanks!

[rgh0]

Hi Greg
Take care with the storms. Try the MT90 if you find the MTL to thin for your feel.

cheers
Rohan

[pharriso]

I would not use motor oil in a gear box anymore than I would use gear box oil in an engine.
I would not use a standard GL5 75w/80 or 75W/90 gear oil either in the gearboxes. Safe that for the diff
cheers
Rohan

While that is generally true, one has to remember that the 5-speed internals came from the BL Maxi & were designed to run in engine oil.

The attached article may be of use if you do not have it already.

Elan_Lotus-Maxi_5-Speed_Rebuilding-Upgrading-Fitting.pdf

Victor Hollnagel article from GGLC

(1.14 MiB) Downloaded 597 times

[gjz30075]

I do have that article, thanks.

[Chris]

Having built three 5 speed boxes, I can say no matter which oil you use, you will never have a decent gear change unless you eliminate first motion shaft end float, and ensure alignment of selector rods.
Chris

[Davidb]

One gear oil that I have had great success with is Penzoil "Synchromesh". This was apparently developed for the Corvette a few years ago-specifically for use with 'yellow metal' synchro rings as ours have. I have found it to greatly improve the shift quality in both the Ford box and a ZF five speed-friends who have tried it in pre-war cars have been impressed with the improvement in gear changing.
May not be available in the UK but definately all over N.America.

[mbell]

I bought this box as 'rebuilt' from Dave Bean (RIP). He only knew that it was 'rebuilt' from "some guy in England", so our knowledge about this box is a crap shoot.

Well you're doing better than my rebuilt box where a spacer was left out of the nose housing, resulting in not being able to select 4th. I didn't buy it as a rebuilt box, it just came that way in the car (I suspect done before leaving the UK)...

Scroll down in this thread to see pics of Alex's gear stick. I'm trying to emulate this. It's going off to my
machinist for refinement lotus-gearbox-f37/gearbox-swop-t21414-285.html

Thanks so it uses the lower half of the 5 speed gearstick. What is the condition of the 5 speed parts? Are the rubber bellows ok? Is the plastic lower "ball" in one piece?

It's common for the rubber bellow to age and give poor changes and the plastic balls turn to cheese and breaks up.... (I really need to find my a new stick for my box.)

Changing to MTL is a good first step in my opinion.