Brooklyn Beer

Trans oils for a 39 Chrysler w/ OD

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So if I am right in understanding. 70 SAE motor oil in the OD unit and 140 gear oil in the trans?  

 

80 W90 in the rear

 

Only 70W I can find is motorcycle oil.     Anyone have an recommendations

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Benefits of AACA Membership.

The gearbox and o/d  shared the same oil in my car .  They recommend 70 or 90 grade oil  but stated that the 90 grade could cause the the o/d to change slow when cold, plus 70 grade might cause the gearbox to sound a bit loud when hot. So I end up putting 90 grade oil in and had no problems.  But don't use modern oil with additives as they can cause damage to the bronze bushes in the o/d.

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I just went back and read the chapter on Lubrication and glad I asked the question as I skimmed over it too fast.  On page 168 it gives "Transmissions Lubricant Recommendations"  and then "Lubrication of Transmission with Overdrive.".  Shows 70 SAE for summer and 50 SAE winter.   Aircraft or engine oil.  So I guess where can I find the required oil or is SAE 70 motorcycle oil OK?

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Can someone explain to me how the OD functions in 39?  I see it has a cable pull but also a solenoid?

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This is the Shop Manual statement for a 1940 with OD, use SAE50 if the car has OD as compared to SAE 90 if it is only a 3-speed. I have found GL-1/50 weight oil and used for my car.

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The manual for 1939 states SAE viscosity No. 70 for summer, mineral oil.   This is what I could find matching those specs.  61UUPa5q5hL._AC_SL1000_.jpg

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It should be fine. Mineral oil in that context just means petroleum oil. Not whale oil, not vegetable (castor) oil, not some fancy special blend for hypoid or limited slip rear axles, not automatic transmission oil..... just.... oil.

 

Was that SAE 70 they recommended gear oil, engine oil, or aircraft oil? SAE 70 on the gear oil scale is about the same weight as SAE 10 on the engine oil scale, so it probably matters.

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OK, found out the NAPA some 20 miles away has GL-1 SAE 90 gear oil. Will be grabbing that.   Found (an lost) an article with a viscosity chart showing that SAE 50w motor oil is very close to SAE 90w gear oil.  That had me confused for a minute with hypoid lube.

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Found the correct lube at NAPA.  GL-1 90 sae gear oil (Mineral).   14.55 a gallon was a deal.

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On ‎5‎/‎19‎/‎2020 at 7:46 PM, Brooklyn Beer said:

Can someone explain to me how the OD functions in 39?  I see it has a cable pull but also a solenoid?

 Thanks for asking B-B.

I would like to know the reason for the solenoid too.

I don't have an indicator light in the instruments or on the dash, so what's it for ?

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The indicator light is actually in the center of the headlight switch.  I have the original owners manual. On 39's the OD function to go in is strictly mechanical. Now to kick it out when climbing a hill there is supposed to be a switch that is throttle linkage activated. This switch gives a "stutter" in the distributor for a split second as the solenoid on the trans kicks it out of OD is the way I read it.  The relay on the drivers fender powers the whole mess off the starter terminal. The fuse in the relay is suppose to blow if the system to kick it out of OD is engaged for too long and renders the kick down useless till you replace the fuse.  I have everything put the linkage switch.  Mine goes into OD nicely but have to find the sweet spot when shifting from second into third.  Like 26 MPH which a slight hesitation when depressing the clutch and holding it out a split second and feeling the "clunk".   I know when it it goes in because the RPM's from normal 3rd compared to OD is like night and day.  When I got the car it is in free wheel right now and have been wondering if I should see what happens by pulling the knob out to disengage.  But it runs good now as is. Brakes fine.  They really beefed up the brakes with that free wheeling option.  Same in my 31 Plymouth.

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Thanks, but mine is a '31 CG, and the headlight /parking light switch is a lever on the steering wheel.

I don't see a light in the center of the wheel, and don't see any unaccounted for wires down at the clum switch.

Guess I'll have to re read the manual for '31's.

 

Mike in Colorado

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Brooklyn,

In my limited experience it goes like this.

The cable lever pushed in is in OD, the cable lever pulled out is out of OD.

Out of OD does away with the free wheeling effect and lets you use the compression, just as if there was no OD at all.

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Gotcha.  I am just worried if I pull it out it might not go back in !

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look at the other end, you should be able to take the cable off of the lever on the tranny.

But, yes, old push pull cables often need replacing.

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Think I am going to keep it in freewheel / OD mode.  Not much but flat land around here minus the one hill out front.

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15 hours ago, Brooklyn Beer said:

Sorry, I don't anything about the 31. 

 

Apparently, neither do I.

Had her for over a year now and I've always been afraid to pull the cable.

When in doubt, read the book...........

 

Mike in Colorado

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4 hours ago, JACK M said:

Brooklyn,

In my limited experience it goes like this.

The cable lever pushed in is in OD, the cable lever pulled out is out of OD.

Out of OD does away with the free wheeling effect and lets you use the compression, just as if there was no OD at all.

 

Jack, My '31 CG is backwards of your description.

My cable is pushed in and I have compression braking.

I validated that the cable is hooked up to the lever @ the Tx.

Now I'm trying to discover what the big solenoid on the drivers side of the O.D. unit is for and where it's 2 wires go.

 

Mike in Colorado

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48 minutes ago, FLYER15015 said:

 

Jack, My '31 CG is backwards of your description.

My cable is pushed in and I have compression braking.

 

The CG series did not have OD as any OE equipment, but rather a non-synchronized 3-speed with a super-low crawler gear added for a total of 4 manual speeds. In the 80s I read that it was popular to refit the large 31/33 Imperials with a late 30s OD unit to gain synchromesh and better overall ratio for cruising which I guess is done to your car. You should get under the car and find some numbers to determine where your trans origins from. Pulling the cable normally locks out the OD and freewheel.

 

In the 1940 Owners Manual you are recommended to stop the car before locking out Overdrive, eg before a long downhill. The automatic underdrive (kick-down) was introduced for either 1939 or 1940, before that the only OD activation control was by pulling/pushing the handle.

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The kickdown came out in ‘39 with the “cruise and climb” transmission as @Brooklyn Beer was describing, above.  I’ve climbed some steep ascents in 3rd, thanks to that nifty feature.

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Wish I could find the linkage switch but so far that part is unobtanium.  The relay was easy. Have a new wiring harness ready to go come fall.  But that stupid switch !  I do like how the O/D is about automatic.  Lower speed when shifting to third it is in third. Higher speed shift into third it is O/D.  That is without kickdown hooked up.  Been really driving mine a lot since getting it now with new tires on it. Starter rebuild is next and to try and found out why the genny needle bounces all over for the first 10 minutes. Rear diff needs a new gasket. I know the sync's are worn in the trans as I have to double clutch (and wait) to go into 2nd when cold.

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There is nothing cooler than a electric controlled Borg Warner overdrive with all it's electrical doodads working. It also makes an small engine much more usable than it would be otherwise.

 

I would try some different oil in the trans before you condemn it. 90 weight is really balky when cold in anything. It is something people lived with back in the day, but today almost everything is multiviscosity. Maybe some Synchromesh oil or even some 10W30 or 20W50 motor oil. If it still crashes then you do indeed have a problem.

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