1949 Plymouth transmission fluid

[49Dluxe]

I have a 49 Plymouth Deluxe with the original 218 engine and 3 on the tree transmission. I’m looking to change the transmission and rear differential fluids, but I haven’t found any specs in any of the manuals I’ve read. What oils would you recommend?

[FarmerJon]

There will be some disagreement on this, as is the case of all oil discussions, but Mopar in the '40s recommend GL1 80w.

Hypoid lubricant is not recommend, although some modern versions have removed the componests that were thought to effect the bronze synchro rings. 

I will try to look at my late '50s mopar books to see what they recommend by the end of the '50s, but the early '60s-80s they called for Dexron ATF.

The Mopar 3 speed shares its general architecture with many of its peers, so much so that many Ford, Studebaker, Jeep, Nash/AMC BW transmissions share the same part number synchro rings.

It also is the direct ancester of the 833, and it shows.

 

Here is what Nash recommend in its version, in the mid '50s

Ignore the Overdrive, that recommendation is the same as the non-OD transmission section, but that one is on a page split.

 

So, what works? Most Oil.

75w-80 GL4

GM Synchromesh oil (what I currently run)

Amsoil/Redline Manual Transmission oil 

Motor oil-some people who run this use the motorcycle type oil, that is wet clutch compatible. 

Dexron ATF.

 

What to consider avoiding:

Hypoid gear oil

Ultra heavy oil in cold climates

Synthetics that cause gear clash or excessive leaking.

 

Good luck!

Edited February 24 by FarmerJon

[Sam Buchanan]

Redline MTL provides excellent service with no gear shift crunching in my manual transmission cars ('48 Plymouth, '69 VW, '74 TR6) with no concerns about corrosion of brass syncros in these transmissions. It is a little pricey but in my opinion an excellent value due to how it keeps these old trannys happy. The modern GL oil is too slippery in the my P48 and causes crunchy shifts when cold. The diff can use the modern GL oils.

 

Edited February 24 by Sam Buchanan

[Sniper]

Not sure what manuals you're looking at but the factory manual calls for gl1. Which you can buy at Napa.  that's what I put in my 51 2 years ago when I changed my transmission fluid. Also changed my gear oil and I used, I think, gl4. I used the viscosity recommendations in the factory service manual. You can buy a copy of the factory service manual from RockAuto. I believe the specifications are listed in the very first chapter.

Edited February 24 by Sniper

[Booger]

5 Plymmies in 50 years (3 49s) always 90w front and back. Just keep em topped off

[Los_Control]

I'll tell you what I did .... does not mean it is correct.

The key is to read the label on the bottle and you are looking for words such as .... Protects against rust, foam, high temperature, and corrosion of copper or bronze bushings.

 

I once found a chart that had the differences of GL1 through GL5 oils ..... Wish I would have saved it.

Basically when our cars were new, GL1 is all that was available. .... The chart said that was good for heavy hydraulic equipment that sat outside and basically not that important. .... but it did have some very good characteristics such as resisting condensation.

 

Then improvements came along with GL2, 3, 4, 5, far superior oil. ..... By the time GL4 came out, the automobile manufacturers were no longer using copper, bronze, or other soft metals in gear boxes. ..... They stopped adding the needed additives to protect these softer metals .... then there were failures in older vehicles and many complained .

 

Not sure when the oil companies started back at adding the correct additives for older vehicles .... maybe not all oils have it. So you have to read the label to see it does have it!

 

I'm using walmart supertech synthetic oil GL5 85-140 because thats what available to me .... it has the correct additives ... or claims too for our old cars.

Thats what you need to look for ..... you may have your own oil brand preferences, you need to see it has the additives for your vehicle.

 

The research I have done on walmart super tech engine oil, The 5/30 I run in my daily driver is the same as Mobil1 synthetic. .... It is made in the exact same plant but it is put into different bottles with different labels for walmart ..... And $10 cheaper.

 

Choose your own oil, just be sure it has correct additives for older vehicles.

[Sniper]

It's fine to update your stuff. I have no problem with that. But I figure hey, it's lasted 70 years on GL1. I think GL1 proved itself to me anyway.

[Los_Control]

2 minutes ago, Sniper said:

It's fine to update your stuff. I have no problem with that. But I figure hey, it's lasted 70 years on GL1. I think GL1 proved itself to me anyway.

You're just not cheap like me .... I get synthetic GL5 for about $20 a gallon .... GL1 at a specialty house is over $10 a quart ....

 

 

Says the guy that is currently replacing the pinion bearing on his daily driver that runs the same oil ....

In fairness I can not blame the oil on a vehicle that has over 400k miles on it ..... possible it is my choice of oil but no way to confirm it.

I'm changing the bearings but not the oil.

 

[Sam Buchanan]

1 hour ago, Los_Control said:

You're just not cheap like me .... I get synthetic GL5 for about $20 a gallon .... GL1 at a specialty house is over $10 a quart ....

 

 

$10 a quart is a bargain......Redline is $23 per quart. But after putting up with a crunchy first to second shift until the tranny got hot, I consider the Redline to be a bargain since it totally fixed the crunchy shift. If I hadn't spent the money on Redline I would be reminding myself of my stupid thriftiness every time I heard second gear not engage smoothly. Now I congratulate myself for spending only $46 to fix this transmission! Would GL1 have worked as well? It might have....but at this point it doesn't matter.

 

It's a matter of perspective........   

Edited February 25 by Sam Buchanan

[Los_Control]

17 minutes ago, Sam Buchanan said:

$10 a quart is a bargain....

What I meant is, I buy it by the gallon.

I buy walmart super tech for $19.98 per gallon .... Then the name brands are always $25-$30 a gallon. .... $10 more.

I have researched and found the cheaper walmart oil is basically same quality ..... simply does not have the same packaging as the name brand oils.

 

This is what I do, I understand others have their own preferences.

 

[Booger]

have we gotten off topic here? synthetics are useful in engine oil. Go to whatever church you like there. But gear oil is gear oil. 80w-90. Done

(and OBTW nothing wrong with Yalmart 10-30)

 

[p15-1948]

6 hours ago, Los_Control said:

I'll tell you what I did .... does not mean it is correct.

The key is to read the label on the bottle and you are looking for words such as .... Protects against rust, foam, high temperature, and corrosion of copper or bronze bushings.

 

I once found a chart that had the differences of GL1 through GL5 oils ..... Wish I would have saved it.

Basically when our cars were new, GL1 is all that was available. .... The chart said that was good for heavy hydraulic equipment that sat outside and basically not that important. .... but it did have some very good characteristics such as resisting condensation.

 

Then improvements came along with GL2, 3, 4, 5, far superior oil. ..... By the time GL4 came out, the automobile manufacturers were no longer using copper, bronze, or other soft metals in gear boxes. ..... They stopped adding the needed additives to protect these softer metals .... then there were failures in older vehicles and many complained .

 

Not sure when the oil companies started back at adding the correct additives for older vehicles .... maybe not all oils have it. So you have to read the label to see it does have it!

 

I'm using walmart supertech synthetic oil GL5 85-140 because thats what available to me .... it has the correct additives ... or claims too for our old cars.

Thats what you need to look for ..... you may have your own oil brand preferences, you need to see it has the additives for your vehicle.

 

The research I have done on walmart super tech engine oil, The 5/30 I run in my daily driver is the same as Mobil1 synthetic. .... It is made in the exact same plant but it is put into different bottles with different labels for walmart ..... And $10 cheaper.

 

Choose your own oil, just be sure it has correct additives for older vehicles.

 

Many companies make a WalMart branded product.  WM came to our industry and wanted a basic product, at a much-reduced price, that they could sell for less than our national name brand product.  Not saying your oil isn't Mobil1, but I don't think Mobil could sell it to WM at a price WM could sell it to you for $10 less than Mobil's product without making changes in the formula.  Also have seen store brand tires built on the same line as a national brand tire.  The store brand tire weighed about 10% less than the same sized tire of the national brand. 

[D35 Torpedo]

Im using sychromesh. Its a gl3

[FarmerJon]

This publication is generally aimed at 745 and 903 transmission but the standard 3 speed, derived from our old '40s jalopys, was still in use in the Valiant and Dart for another year, so it got the same fluid update. The 745 and 903 have very similar bronze parts, roller bearings, and general architecture to our old boxes.

Per Chrysler, ATF is compatible and interchangeable with the 80w oil previously recommended. 

In the '40s there were no better options, 10 years later Chrysler (and other makers) knew this, and took advantage of the cheap, easy improvements of better fluid. If these guys had access to the dedicated manual transmission lubes, like GM Synchromesh, Redline and Amsoil MTL, they would likely use that. 

 

If you are bringing a car or truck back from the dead, sure- use whatever is cheapest to get the old tar out of the box. 

But for a decent driver, the added $10-25 is trivial, and as @Sam Buchanan, myself, and others have found, can really breath new life into an old transmission. 

[49Dluxe]

Thanks everyone for the responses! It sounds like there’s a few decent options out there. I’ve heard that this topic is a point of contention for many, but it’s still good to hear everybody’s experiences.

Edited February 28 by 49Dluxe

[Booger]

Heres the thing 49. Back in 49..

Your car used 30w (probably detergent motor oil) and the 3 sp manual tranny was a no brainer 80-90w and the rear end as well. So lets over engineer everything and decide what worked then is no good now. 

[Sam Buchanan]

9 hours ago, Booger said:

Heres the thing 49. Back in 49..

Your car used 30w (probably detergent motor oil) and the 3 sp manual tranny was a no brainer 80-90w and the rear end as well. So lets over engineer everything and decide what worked then is no good now. 

 

Ok.......guess we ditch the 3000 mile oil change intervals, radial tires, 12v conversions and electric wipers.................  ?

[Sniper]

36 minutes ago, Sam Buchanan said:

 

Ok.......guess we ditch the 3000 mile oil change intervals, radial tires, 12v conversions and electric wipers.................  ?

Just because something is new doesn't make it better.  I give you gangster rap as an example, lol.

 

Seriously, we drive 70+ year old cars.

[Sam Buchanan]

5 hours ago, Sniper said:

Just because something is new doesn't make it better.  I give you gangster rap as an example, lol.

 

Seriously, we drive 70+ year old cars.

 

That is not at all what I said. I'm just observing the lack of consistency of some who strenuously promote certain elements of the "old school" while adopting modern tech at the same time. But I respect the prerogative of owners to operate our old cars in whatever manner they wish. 

 

My old car has an alternator, fancy transmission oil.......and bias ply tires.  

Edited February 29 by Sam Buchanan

[FarmerJon]

[Booger]

I suppose we need not worry about the simplicity of plain ol 30w motor oil anymore. Cuz ya cant find it. (lest not Yalmart no mo)

[Sam Buchanan]

21 minutes ago, Booger said:

I suppose we need not worry about the simplicity of plain ol 30w motor oil anymore. Cuz ya cant find it. (lest not Yalmart no mo)

 

Not much reason to use straight 30W, 10W-30 is an excellent option readily available and reasonably priced. It has the same viscosity as straight 30W when hot but makes cold starts easier when it is similar to 10W. But 30W is still available, just takes a bit of effort (or place an order on Amazon).

 

 

Edited February 29 by Sam Buchanan

[Sniper]

3 hours ago, FarmerJon said:

 

 

One fallacy in your meme,  GL1 isn't cheaper.  My transmission is 73 years old, I think GL1 has proven itself and I am in no mood to experiment. 

Net time you have gear crunch drain your ATF and put in gear oil.  Bet it goes away, btdt.  So much for "better". 

 

As for the rest of your meme's claims. 

 

Disc brakes are better.

Electric fans save fuel and allow more of your of the flathead's meager hp to hit the road.

Electronic ignitions are better.

[Sam Buchanan]

12 minutes ago, Sniper said:

 

 

One fallacy in your meme,  GL1 isn't cheaper.  My transmission is 73 years old, I think GL1 has proven itself and I am in no mood to experiment. 

Net time you have gear crunch drain your ATF and put in gear oil.  Bet it goes away, btdt.  So much for "better". 

 

As for the rest of your meme's claims. 

 

Disc brakes are better.

Electric fans save fuel and allow more of your of the flathead's meager hp to hit the road.

Electronic ignitions are better.

 

I saw the meme not as passing judgment on disk brakes, etc but as observing how some will insist on the "purity" of something like old-school lubricants while sanctioning upgrades to other components of their car. I thought the meme was amusing and to-the-point......well played. 

[kencombs]

OK, I'll give my 2cents on the trans oil discussion.   IMO it all depends on the condition or the synchronizers themselves.    Good, tight, little wear, good grooves in the contacting faces, those would get ATF in my trans.    More wear, may require something closer to the original.

 

I base this on the factory recommendation from around the mid 60s.   The A833 in my 65 Dart came with Type A from the factory, as did most. There where a few complaints of a gear rattle in neutral from some owners so Mopar suggested a change to 80w90 for those only.  

 

That little Dart was the best shifting standard trans I've ever driven.   That's why the one waiting to go in my 56 pickup already has ATF in it.