Our LRDG Chev

[Andrew H.]

Hi Lynn,
Thanks for your helpful comments. We turned the shaft down a little, as it was slightly pitted, so the standard-size roller bearing will probably no longer fit. We won't use an EP oil in the gearbox, if that is not compatible with the bronze bush. I understand that the bush will only be under load in low gear and reverse. I am pretty sure we took the inner seals out of the bearings, but will check that again before we bolt the top cover on. Is the oil-slinger on the output shaft really necessary if we use sealed bearings? If so, we will have to find one from somewhere (maybe someone here has a spare one?). I should mention that we are a team of three, and the other two have a lot more expertise in gearboxes than I do.
Andrew

[Lynn Eades]

Andrew, I don't know what the inside of your g/box looks like.
It's just that the slinger is usually held with the bearing on the mainshaft, by a circlip. If you don't have a slinger in there, the shaft can then float back and forward. This affects other things, which is not good.
The slinger is usually to divert the oil from the seal, but it may also be there for a secondary purpose, to lube the selectors forks, selector shafts, interlock, detents etc. I am just having a guess and may well be wrong.

In saying that there must be someone around that has a donor Chev g/box, with a slinger in it.

[Lionelgee]

Originally Posted by Lynn Eades

Andrew, I don't know what the inside of your g/box looks like.
It's just that the slinger is usually held with the bearing on the mainshaft, by a circlip. If you don't have a slinger in there, the shaft can then float back and forward. This affects other things, which is not good.
The slinger is usually to divert the oil from the seal, but it may also be there for a secondary purpose, to lube the selectors forks, selector shafts, interlock, detents etc. I am just having a guess and may well be wrong.

In saying that there must be someone around that has a donor Chev g/box, with a slinger in it.

Hello Andrew,

Following on from Lynn's email about the work of the "slinger". Have a look at this Chevrolet Instructional Video which shows what the work the slinger does in distributing the oil within the engine.

Accessed January 11 2016 from, Motor Oil: "Riding the Film" 1937 Chevrolet Engine https://www.youtube.com/watch?v=vz2p1SvuYjY

Hopefully the sound works on your link. My computer is playing games at the moment

Kind Regards
Lionel

[Richard Farrant]

Originally Posted by Andrew H.

Hi Lynn,
Thanks for your helpful comments. We turned the shaft down a little, as it was slightly pitted, so the standard-size roller bearing will probably no longer fit. We won't use an EP oil in the gearbox, if that is not compatible with the bronze bush. I understand that the bush will only be under load in low gear and reverse. I am pretty sure we took the inner seals out of the bearings, but will check that again before we bolt the top cover on. Is the oil-slinger on the output shaft really necessary if we use sealed bearings? If so, we will have to find one from somewhere (maybe someone here has a spare one?). I should mention that we are a team of three, and the other two have a lot more expertise in gearboxes than I do.
Andrew

Hi Andrew,
Using a bronze bush is OK as that is what the Bedford version of the Chev box had, but you should have oil scrolls in it to allow the oil to get around the bush, inside and out.
The other point, if you have left the seal in the output bearing on outer side, this will not allow oil to get to the speedo drive (I see this is a 4x2 so drive should be fitted).

[Phil Waterman]

HI Andrew

Here is the link to the page on my C60S so you can compare what my gears looked like, also has the Canadian Chevy parts book explode parts page showing 1938-1951

http://canadianmilitarypattern.com/C...ansmission.htm

Cheers Phil

[Peter Phillips]

I've been watching this build and am amazed at the level of detail, bravo! As for the gear oil issue, I went through an extensive search to find an oil for my 52 M38Cdn. Chevron makes a 90W or 140W GL-1 oil which is safe for yellow metals. Todays GL-4 or 5 will deteriorate yellow metal over time time due to the sulfur content. I paid approx $100 Cdn for a 5 Gallon pail. Keep up the good work

[Andrew H.]

Thanks Guys,
Some interesting responses there and also brilliant photos from Phil. I will discuss with my two partners whether we need to re-think what we are doing with the gearbox, before its final installation. It might be a few days before I can report back here. In the meantime, if anyone has a spare oil-slinger lying around in their shed it would be great to hear from them

[David Dunlop]

Andrew, you truck is looking amazing! Are you dreaming of the sand in your face and grinning like a Cheshire Cat when you finally get her out for a run yet?

David

[Andrew H.]

Originally Posted by David Dunlop

Andrew, you truck is looking amazing! Are you dreaming of the sand in your face and grinning like a Cheshire Cat when you finally get her out for a run yet? David

Actually we joke among ourselves that by the time it is finished we will be either dead or too old to enjoy it! (we are getting on in years). But yes, we do dream of driving her through the Libyan desert behind enemy lines with the wind in our hair while squinting down the barrel of a Vickers 0.5. Unfortunately there are not many deserts here in NZ to try her out on.

[motto (RIP)]

Your truck will be too good to take it off road but I had a '42 model Chev 3 ton 4x2 for many years and it is quite surprising where they will go. Many dismiss them as an old grocers truck but with their ground clearance and low first gear, four wheel drive doesn't give as much advantage over them as you may think.
I have very fond memories of my truck that is now in the UK, my wife and I having driven it there from Istanbul in 2009. I do miss it.

David

[Andrew H.]

A quick update: We decided (due to Richard Farrant's suggestion) that we should put an oil groove in the brass bush in the gearbox. Luckily, my neighbour is a precision engineer and he did it at no cost . He is a true craftsman and set the lathe up carefully, using a dial-guage to get the measurements exactly right. The only way he could do it in his lathe was to make several spiral grooves, rather than a single groove but we saw no problem with that. First he cut an annular groove from the oil hole around the full circumference inside the bush. Then he got the lathe to cut a spiral groove about 1mm deep and 1mm wide from the oil hole to the front at 6mm spacings. That gave three full spirals over the 23mm length of the bush. In one of the pics he is turning the lathe by hand to achieve more control, but mostly it was automated with both axis of the lathe working in unison. The blue tape is there to keep the brass filings out of the bearing. Another small step