New Game CMP Brain Teaser Trivia

[Phil Waterman]

Hi All

New game for those of you who spend to much time working on, playing with or studying CMPs. CMP Brain Teaser Trivia, object to post a simple question about CMPs Ford or Chevy, question should be something you have observed, read about, or been curious about.

Question #1 On Chevy CMPs what gear do you put the transmission to check the lube level?

Cheers Phil

[Grant Bowker]

Question for the game moderator - Do we have to know the answer to the question we post or are we allowed to ask about things we are curious about but have no answer to?

[Howard]

Originally Posted by Phil Waterman

Question #1 On Chevy CMPs what gear do you put the transmission to check the lube level?
Cheers Phil

It matters?
H

[Phil Waterman]

Hi Grant

We had to go to the instant replay booth for a review of the ruling on the field.

No you don't have to know the answer question.

Cheers Phil

[Richard Farrant]

OK, to dive into Phil's question. I see that due to the plan view of the gearbox casing, at oil level height, it is slightly irregular, and by selecting a gear, ie sliding one of the gears along the mainshaft, it might displace a few cubic centimetres of oil in doing so, but it is hardly worth considering as when the gearbox is revolving, the level is not maintained as oil is everway and whichway around the box.
Not seen any note of selecting a gear before checking oil in any Chev or Bedford box (Bedford is basically a Chev design) in official manuals. Do not think the CMP gearbox is any different to aforementioned.

Hope this opens the discussion !

cheers Richard

[Tony Wheeler]

Not familiar with the Chev box but does it have anything to do with finger access?

[Phil Waterman]

Hi

Richard raises an interesting point, which I'll have to verify the next time I have a Chevy gear box out on the bench to see if the level changes depending which gear is selected.

Tony is getting very close but lets see if anybody can add to the reason.

Cheers Phil

[Richard Farrant]

Originally Posted by Phil Waterman

I'll have to verify the next time I have a Chevy gear box out on the bench to see if the level changes depending which gear is selected.

Hi Phil,
The level should not alter where ever the gears are as they are only displacing the oil from one side to the other. I was thinking this a trick question as never seen any reference to it in the publications.

[Phil Waterman]

Hi Richard

I've gone back to see if I pick this up from any manual and didn't find this in any of them either. This is just something you pick up after lots of years taking care of Chevy CMPs.

I had to stop and think about the displacement change, I was thinking of the 3rd to high engagement on the main shaft but that is above the static level of lube in the transmission.

A hint this is both about checking the level and putting lube in. If you have ever had trouble get lube in this may explain why.

Cheers Phil

[Tony Wheeler]

Originally Posted by Phil Waterman

A hint this is both about checking the level and putting lube in. If you have ever had trouble get lube in this may explain why.

I'm only guessing here, but if the filler hole is obstructed internally it can cause the oil to flood back out suddenly, giving the impression of full. I recall this happening on some car gearboxes in the past, and you have fill them very slowly to avoid floodback. It taught me not to trust floodback as an indication of full, and always wait for it to subside and do the finger check again. The temptation is to quickly put the filler plug back in to avoid a big mess on the floor, but that can lead to underfill.

I must confess though it never occurred to me to change gears, perhaps because I was working on lots of different cars and I never became familiar enough with their gearbox internals. However the problem is severe enough on some cars that you can't even insert the filler nozzle properly, and you have to hold it place and pump the oil in excruciatingly slowly. Maybe that's the case with the Chev gearbox in neutral...?

[Lynn Eades]

It has to be about moving 1st gear (mainshaft, big. gear) out of the way.
So my guess. You put the trans into 1st gear.

[Keith Webb]

Here's one for those outside Australia to answer (Mike C please hold off for a moment)

Why is the cowl vent on most CMPs found in Australia a different shape to those elsewhere?

[Tony Wheeler]

Here's one for Australian CMP owners, although anyone can have a crack at it:

In what way do chassis siderails produced for Australia differ from all others?

[Phil Waterman]

Hi All

You are getting closer but not quite.

I put a transmission up on the bench today and photographed the relative position of the all gears in each gear range. So once we have an answer I'll post the pictures.

Think about which gear is closes to the filler hole.

Cheers Phil

[Richard Farrant]

Originally Posted by Phil Waterman

Think about which gear is closes to the filler hole.

Reverse gear?

[Tony Wheeler]

Originally Posted by Phil Waterman

Think about which gear is closes to the filler hole.

Having just looked at a Chev gearbox from the outside and discovered the filler plug is on the rear face of the housing, offset well to the RHS and located on a bulge in the casting, the answer has to be reverse gear. That is, reverse idler gear would blank off the filler hole in neutral. Quite poor design IMO.

[Howard]

Originally Posted by Keith Webb

Here's one for those outside Australia to answer (Mike C please hold off for a moment)
Why is the cowl vent on most CMPs found in Australia a different shape to those elsewhere?

Is Ganmain counted as outside Australia?
No?

[Howard]

Originally Posted by Tony Wheeler

Here's one for Australian CMP owners, although anyone can have a crack at it:
In what way do chassis siderails produced for Australia differ from all others?

ALL chassis lengths, Tony? Or just, say, long WB's??
H

[Grant Bowker]

Originally Posted by Keith Webb

Why is the cowl vent on most CMPs found in Australia a different shape to those elsewhere?

A. They were already tooled up for that shape for another model (but I've no idea what model that might be)
B. Just to be different
C. To provide an identifying point for restorers 70 years in the future.

[Grant Bowker]

Originally Posted by Tony Wheeler

In what way do chassis siderails produced for Australia differ from all others?

Is the precise wording a clue? In other words, is there a difference in rails made in Canada for Australian use compared to those for Canadian or British use? Is the difference you are seeking common to Ford and Chev?

[Phil Waterman]

Hi Guys

Richard, got it first and Tony got it second. You win less gear lube dribbling down your arm the next time you have to add lube to your Chevy transmission.

Picture of Spare Transmission

Transmission in Neutral

Transmission in 3rd gear (the spacing is the same for all forward gears)


See the next post for the difference with transmission in Reverse.

[Phil Waterman]

Hi Guys

Now for the difference in Reverse



As you can see in the middle picture above there is about an inch more clearance in side the box with transmission in reverse.

As the plug is located in a position almost impossible to actually look in on the truck, I remove the plug an insert a finger (clean of course) and crock the first joint to check the level.

Now for curiosity here is the top cover with all the forks set for Neutral I have a copy of this picture and one looking down into the transmission with all the gears in the neutral position as reference in the shop.



The last picture is transmission tick tac toe for where are the different forks positioned for what gear.



Note of explanation: The reason for all the grease on the gears, this is my spare transmission that have repaired after breaking a tooth. As this one is in storage want to really protect it from rust so I coated everything inside in a heavy layer of grease. Then sealed all the opening as much as possible.

Story of breaking the tooth http://www.mapleleafup.net/forums/sh...ighlight=tooth


Now for you Ford guys is there one gear better than another for checking the lube?

To sum up

What gear should you put a Chevy CMP to check the lube level in the transmission?

Answer

Reverse as this moves the gear closest to the lube fill plug away by an inch. Allowing for easier checking and easier adding of lube if needed.

Side point don't over fill it just makes them leak more.

Cheers Phil

[Richard Farrant]

Well Phil,
I know the box is virtually identical to that used on the WW2 Bedford trucks, but had forgotten how Chev put the level plug at the back. The British arm of GM had the level plug in the side so none of these dramas.

Bedford also redesigned the Chev 216 into the Bedford 28hp, which had full pressure lubrication to mains and big ends along with replaceable shell bearings ...... oh and no fibre cam gear either. All this before the first Chev CMP's went into production too!

[Tony Wheeler]

Originally Posted by Howard

ALL chassis lengths, Tony? Or just, say, long WB's??
H

Yes it applies to all chassis lengths Howard.

[Tony Wheeler]

Originally Posted by Grant Bowker

In other words, is there a difference in rails made in Canada for Australian use compared to those for Canadian or British use? Is the difference you are seeking common to Ford and Chev?

Yes to both questions Grant. It's a tough question if you're not familiar with Australian CMPs. Even then it's pretty tough!

[Richard Farrant]

Originally Posted by Tony Wheeler

Yes to both questions Grant. It's a tough question if you're not familiar with Australian CMPs. Even then it's pretty tough!

Hi Tony,
Would this difference also involve those CMP's sent to India as well? I am aware the Indian ones had heavier steering boxes so maybe the chassis was heavier / thicker?

Richard

[Tony Wheeler]

Originally Posted by Phil Waterman

Now for you Ford guys is there one gear better than another for checking the lube?

No such issues Phil, the filler plug is on the side of the box, well clear of the gears. It's also angled downwards about 45 degrees, so your finger could reach down further to check the level. All very considerate of Ford, unlike the dizzy!

Interesting to compare the two gearboxes, I've never looked inside a Chev box. The Ford one seen here is in 3rd gear. Reverse idler and selector fork can be seen top left. It's on a half length shaft, unlike the full length Chev one. As you can see Phil I couldn't quite match your maintenance standards!

[Mike Cecil]

Keith,

You are being mischievous! Fancy dropping such an 'isolated' question on the poor overseas CMP-ers!

Common guys, I'm out of the running, but Grant's answer A is getting close to the money. More info needed: look at some pictures of Aussie trucks (sorry, Lorries)

I could ask a question or two of CMP owners in Australia: what's the difference between the lower back of Canadian Ford Cab 13 and the one found on Ford CMPs assembled in Australia, and why?

And while on the subject of cab backs, what's the difference in the fastenings of the roof to cab back on Ford Australia assembled cabs, than those assembled by Ford in Canada??? (and why??)

Keith already knows, so he's out already.....

Mike C

[Keith Webb]

Originally Posted by Grant Bowker

A. They were already tooled up for that shape for another model (but I've no idea what model that might be)
B. Just to be different
C. To provide an identifying point for restorers 70 years in the future.

Yes you are correct there Grant... and seeing Mike thinks the question is unfair perhaps I'll post a supplementary one...

What approximate percentage of the

A Chevrolet cab 13

and

B Ford cab 13 was locally made in Australia?

[Lynn Eades]

Just for the record, many parts in that Ford box are interchangeable with the Dodge 4 speed built under the "New Process" brand.