Chevrolet 1533X2 30-cwt trucks

[Grant Bowker]

Again by parallel to CMP, Ford and Chevrolet may have used different rear axles. The ones shown appear to match Chevrolet casting style (not a Ford split axle). I don't know how Ford handled 2 speed axles - whether with a split housing, a GM style banjo or a pure "supplier" axle (Eaton, Timken, Spicer etc.). I will try to dig into this more later.

[Colin Alford]

Gents,

While I have never been particularly interested in MCP vehicles, I now realize that I have access to some manuals that can very likely answer some of the questions that have been posed on this forum.

The reason it took me this long to realize is that I looked at these as CC60L manuals, and didn’t make the connection to the Chev model numbers 1542, 1543, etc.

I will attempt to provide some assistance.

Colin

[Colin Alford]

Since this thread is primarily about 1533X2, but no-one seems to have a parts manual for it, let’s start by using the Major Assemblies book to see what vehicles shared the same major components as 1533X2.

Here is the data regarding engines for Chev MCP vehicles.

Both 1533X2 and 1543X2 used engine assembly 5269525. It appears that the significant difference between this engine, and other MCP engines, was a six-bladed fan, with a spacer between fan and pulley.

[Colin Alford]

Transmission,

While the transmission was visually similar to other CMP and MCP types, if we look at the bottom of the conversion chart, only 1533X2 and 1543X2 used the same speedometer drive gear.

[Tony Smith]

Originally Posted by Colin Alford

Transmission,

While the transmission was visually similar to other CMP and MCP types, ... only 1533X2 and 1543X2 used the same speedometer drive gear.

Because the Speedo Drive gear ratio has to be related to the specific Differential Ratio and tire size.

1531 and 1541 had 6.16:1 gears and 17" wheels
1542 had 6.16:1 gears and 20" wheels
1533 and 1543 had Eaton 2 speed diff and 16" wheels.

The Eaton final ratio was dependant on the particular ring and pinion gears fitted with a fixed reduction in the 2 speed gears. Typical ratios of the 40's were 5.83/8.11 and 6.33/8.81 ratios. Note that the Hi ratio in either of these combinations is not the same as the 6.16 of the Chev differential, so a unique speedo drive gear ratio has to be use with the Eaton.

Now if Bob Carriere would be so good to look in his 1543X2 parts manual, we might determine the actual diff ring/pinion ratio.

[Tony Smith]

Originally Posted by Grant Bowker

Again by parallel to CMP, Ford and Chevrolet may have used different rear axles. The ones shown appear to match Chevrolet casting style (not a Ford split axle). I don't know how Ford handled 2 speed axles - whether with a split housing, a GM style banjo or a pure "supplier" axle (Eaton, Timken, Spicer etc.). I will try to dig into this more later.

The Eaton 2 speed differential is of a "Banjo" design, regardless of it's intended vehicle; Chev, Ford, Dodge, Bedford, Leyland. It's still getting about today with some refinements.

[Colin Alford]

Front axle.

While there were 3 possible front axles on 1533X2, they match the last 3 (of 5) types used on 1543X2.

[Colin Alford]

Steering gear,

1533X2 and 1543X2 used the same three types of steering gear. 1542X3 used only the last two types as the others.

[Colin Alford]

That exhausts the information available in the Major Assemblies book.

My read on this information (and the information/study presented above by others) is that “Major Assembly-wise” 1533X2 was essentially the same as 1543X2, but there were definite differences in wheel-base (and therefore frame), cab style, and cargo box.

My inference is that Parts list CC60L-01, and Driver’s Handbook CC60L-HB1 (which both cover 1543X2), are probably reasonable reference materials for mechanical systems in 1533X2 in the absence of the correct manuals.

[Colin Alford]

Tony,

The parts book doesn’t seem to give a good indication of the rear axle ratios, but see the attached image from the Driver’s Handbook.

[Colin Alford]

Power Tire Pump

The conclusions drawn above regarding the Power Tire Pump may be incorrect.

We know that the cabs were different between 1533X2 and 1543X2, but these two different MCP cabs were more similar to each other than they were to a CMP cab.

The description in Driver’s Handbook CC60L-HB1 includes “...is controlled by a lever located on the running board valance to the rear of the front mudguard...the dust cap located to the rear of the control lever...disengage the clutch and pull out on the lever” (see first two images for complete text).

The comparable description in Driver’s Handbook C60L-HB1 (a normal CMP) includes “... is controlled from within the cab...the dust cap from the hose connection at the left frame side rail...insert a screwdriver...turn the shaft counter-clockwise to engage the gears.” (See last two images for complete text and image).

Are there any clearer images of the left running board valance on 1533X2 where we might be able to make out the control lever (knob)?

87AA4C6B-5D8C-44E2-BA9C-61260402FBE9.jpeg

DEED437E-67AA-4F3D-8FF0-C68CA53EABDD.jpeg

3DE90BCD-C78E-4544-B0CB-3DF0F76B32EB.jpeg

94BA1FE7-903B-4B25-8419-955A3F96B0B6.jpeg

[Bob Carriere]

..... I could not find the ratio...it's just not there..... it shows the whole rear end as an assembly but no ratio given........ will dig deeper tonight.....

[Bob Carriere]

I feel like we have beencovering the definition of "sunshine"........

The more you dig/read/find the more you confused you are like a google search find...

so the heading of this thread should be possibly/matbe/perhaps a "30424" which is there plain as sunshine in one publication but not listed in the major assembly book. Glad no one is taking offence at the various new info coming up.

So the question begs to be asked.....are all LRDG 2 speed axles......??? how do we tell them apart...... do we have an inside cab picture that shows an adadded lever on the tranny gear shift lever???

....and now I know where I canfind a 2 speed rear axle....... if the yeard has not rolled everything for crap.... Grant nugg nugg wink wink do you remember????..... I still have a piece of rusted flaked black paint under my RH knuckle.... if only the snow can melt....

Need to hunt for more 42 Chev, GM, GMC, Maple Leaf good sheet metal....

Now that everyone has their best bible open can you cross check somo thing for me........ Shock absorbers........

The CMP early models had small double action Delco..... same used on early 4x4 Dodge trucks.... the VC and WC series I beleive..... Now we know that shock absorbers on the rear axle was an option on civilian models....and civilain models tended to have single action shock absobers in front.

All CMP rear axle have the larger shcokabsorber and eventually all cab 13 had the larger shocks onthefront as well.

What was installed on the larger Chev and GMC........ I have a Chev (41/42?) rolling chassis that sports the small CMP shock absorbers and the infamous flat 1/4 in. steel plate frame reinforcement...... but no other identifying marks....... could that frame be X military???? it has the large ball bearing on the front axle........ what goes on a 304123.....

Cheers