Recommended transmission fluid

[Sniper]

4 hours ago, keithb7 said:

The guts in my 1953 M6 tranny have several similar parts yet it calls for SAE 10 engine oil. Also in my 53 shop manual the 3 speed manual tranny was available. It calls for SAE 10 oil too. It has synchros...That's interesting to me. Why is the tranny oil in a 1938 3 speed SAE 160, yet in 1953 SAE 10? Different synchro engagement design I presume?

 

 

Well my guess would be that little old thing called WWII might have driven major improvements in oil technology as well as materials design

[T120]

I just follow the book..?

 

[RobertKB]

16 hours ago, Sam Buchanan said:

 

If you put motor oil in it and it doesn't shift like you think it should.....is the problem with the tranny...or the oil????

 

Go ahead and buy the good stuff. If you need to go back into the tranny you can drain it and save it.....frugally. If the tranny works well, you won't need to change that oil in our lifetime.   

 

 

 

Ditto!

 

After reading this thread, I decided I will try Red Line MTL 75/80W in the rebuilt tranny of my '51Dodge business coupe. It shifts a bit roughly from 2 to 3 unless I go really slowly. I have been told by a couple of people that I am probably running the wrong oil in it. At present it has GL-5 80/90W.  I'll see if the Red Line makes a difference and post back on this thread.

Edited May 22, 2020 by RobertKB

[RobertKB]

I said I would post back when I changed my transmission oil. I ordered and quickly received 4 quarts of Red Line MTL 75/80W synthetic transmission oil. I ordered four quarts because I could use it in my other two Mopars as well depending on results. Also there was free shipping once I got to four quarts.

 

As mentioned shifting from 2nd to 3rd caused grinding unless I shifted really slowly which quite often meant modern day drivers were up my tailpipe in no time. Shifting 1st to 2nd was OK but still not as smooth as I would like. Anyway, drained the GL-5 80/90W and replaced with the Red Line. Easy job and did not take long. Took the car out around the block and shifting was smoother but still some grinding 2 to 3. This afternoon took the car out and put around 30 miles on it. Shifting got smoother and smoother and by the end the car was shifting very smoothly and 2 to 3 was quick, smooth, and noise free. I reckon that once the oil warmed up and really circulated and got into the brass syncros that is what made the difference. Transmission seemed to run a bit quieter as well. I am very pleased so far. 

 

I will see what it is like starting off cold and report on that in a day or two. My guess is that results will be good. I will also check for any leakage from the tranny as the oil is a bit thinner than what was in there before. 

Edited May 28, 2020 by RobertKB

[RobertKB]

Took the car out this morning. Checked first to see if the slightly thinner oil might have leaked a bit but everything was normal. Took off and shifting with the oil cool was the same as yesterday when the oil was well warmed up. Shifting was smooth and quiet going 1st to 2nd as well as 2nd to 3rd even before the oil warmed up. I have to say I am very pleased with the Red Line MTL 75/80W synthetic transmission oil. I have no affiliation with the company.

 

I now plan on changing the oil in my '48 Dodge and '53 Plymouth as I bought enough to do all three. '53 has always needed to be shifted extra gently going 2nd to 3rd. It could be worn syncos or needs a better oil. I have been running the GL-5 80/90W in it for years. Transmission also has over a 100,000 miles with no attention except for a rear seal replacement. I will report on that transmission oil change as well but it might be a bit down the road.

[Sam Buchanan]

Thank you for the update, glad you have excellent results with the Red Line oil. A happy tranny makes the cost of the Red Line MTL a bargain. ?

Edited May 28, 2020 by Sam Buchanan

[Plymouthy Adams]

 

On 5/22/2020 at 12:54 PM, RobertKB said:

 

Ditto!

 

After reading this thread, I decided I will try Red Line MTL 75/80W in the rebuilt tranny of my '51Dodge business coupe. It shifts a bit roughly from 2 to 3 unless I go really slowly. I have been told by a couple of people that I am probably running the wrong oil in it. At present it has GL-5 80/90W.  I'll see if the Red Line makes a difference and post back on this thread.

not out to point a finger or call foul direct on anyone but I must comment that the man had admittingly placed the GL5 in there where it was NEVER supposed to be in the first place..so I think even the normal GL1 would have had similar results in shifting.....

[Sam Buchanan]

Glad we have an option that we know works. ?

Edited May 28, 2020 by Sam Buchanan

[RobertKB]

2 hours ago, Plymouthy Adams said:

 

not out to point a finger or call foul direct on anyone but I must comment that the man had admittingly placed the GL5 in there where it was NEVER supposed to be in the first place..so I think even the normal GL1 would have had similar results in shifting.....

 

No offence taken, Tim. It is virtually impossible to find GL-1 in Canada although I have been using the GL-5 in transmissions for a long time unaware it is not the greatest for transmissions with brass parts. After following this thread I realized I had probably been using the wrong oil in my transmissions for a lot of years although probably fine in all my differentials. Red Line MTL 75/80W synthetic was the readily available alternative. Very pleased, as mentioned, with the results so far. Live and learn.

 

I will be interested to see what difference it makes in my '53 Plymouth's tired, fairly high mile transmission that grinds a bit if shifted too fast from 2nd to 3rd. This really could be worn syncros unlike by rebuilt '51 transmission.

[Adam H P15 D30]

3 hours ago, Plymouthy Adams said:

 

not out to point a finger or call foul direct on anyone but I must comment that the man had admittingly placed the GL5 in there where it was NEVER supposed to be in the first place..so I think even the normal GL1 would have had similar results in shifting.....

When I changed to the Redline MT fluid, it was a MAJOR improvement over the NAPA GL1 oil.  FWIW...  My issue was a crunchy 1-2 shift, especially cold.  The Redline oil completely solved it

Edited May 28, 2020 by Adam H P15 D30

[Dodgeb4ya]

Now what about the later R10 overdrive transmissions?....some say absolutely no synthetic lubes ?

[T120]

4 hours ago, Plymouthy Adams said:

 

not out to point a finger or call foul direct on anyone but I must comment that the man had admittingly placed the GL5 in there where it was NEVER supposed to be in the first place..so I think even the normal GL1 would have had similar results in shifting.....

 

NAPA GL1 seems to perform okay in the  transmissions of my old cars, never had a problem shifting using it to date....☺️

[keithb7]

After reading all of the great posts in this thread, I am thinking...Good chance my gear grinding with the synchromesh is related to the GL-5 oil I had in my '38 speed tranny. I did order a NOS synchromesh earlier in May here. It was a decent price at $80, but I sure am losing a ton of primetime driving, while I wait for it to arrive. It took 13 days to be shipped within in the CON USA, to E-bay's Global Shipping distribution centre in Kentucky. It left there yesterday. Brutal. It'll be another 7-10 days before I see it here at my home in Canada. Meanwhile I am staring at my disassembled tranny here. Could be ready to go,  with proper oil this time,  if I re-use the old synchro. The days just keep passing by. I am really tempted to just put it back together with the old synchro and see how it runs with the right oil in it. Damn Ebay and their global shipping program. I'm almost out of patience. 

[Dodgeb4ya]

These Mopar transmissions more than likely didn't grind back in the days when in good condition.

But at least there is a synthetic  liquid fix it appears so far.

[T120]

8 minutes ago, Dodgeb4ya said:

These Mopar transmissions more than likely didn't grind back in the days when in good condition.

But at least there is a synthetic  liquid fix it appears so far.

 

[RobertKB]

1 hour ago, keithb7 said:

After reading all of the great posts in this thread, I am thinking...Good chance my gear grinding with the synchromesh is related to the GL-5 oil I had in my '38 speed tranny. I did order a NOS synchromesh earlier in May here. It was a decent price at $80, but I sure am losing a ton of primetime driving, while I wait for it to arrive. It took 13 days to be shipped within in the CON USA, to E-bay's Global Shipping distribution centre in Kentucky. It left there yesterday. Brutal. It'll be another 7-10 days before I see it here at my home in Canada. Meanwhile I am staring at my disassembled tranny here. Could be ready to go,  with proper oil this time,  if I re-use the old synchro. The days just keep passing by. I am really tempted to just put it back together with the old synchro and see how it runs with the right oil in it. Damn Ebay and their global shipping program. I'm almost out of patience. 

I would be patient and wait for the new synchros and order some Red Line. I ordered my Red Line out of a place in Ontario and had it in three days. 
 

You have your gorgeous  Chrysler to drive in the meantime. 
 

I hear you on EBay’s global shipping. I don’t know why any sellers use it. It is incredibly slow and way more expensive than using the postal service. I used to sell a lot of Mopars related stuff on eBay and always used the postal system. Never had an issue whether insured or not. There are a lot of ebayers who have lost sales to me because of the cost of global shipping. Worst thing eBay ever did. So ends the rant!

Edited May 29, 2020 by RobertKB

[keithb7]

You’re right RobertKB. I jumped in my big Chrysler after that post for a relaxing cruise. On a sunny warm spring evening, with the sun dropping, as you peacefully drive into it, with a great song on the radio, absolutely nothing matters. Nothing. 

Edited May 29, 2020 by keithb7

[keithb7]

Saw this ad today in my recent copy of the Hemmings Classic Car magazine.  
 

 

[Sam Buchanan]

What are the odds MPT is the same oil as in the Red Line bottles?

 

https://www.amazon.com/MPT-Industries-MPT386-Transmissions-Transaxles/dp/B07CW44CM2

[plymouthcranbrook]

I had the rear transmission rear seal replaced recently and decided to go with the Redline fluid as a replacement. Haven’t driven it too much as of yet but so far shifting seems much improved. No longer have to shift slowly into second with a pause in neutral.  So far so good. 

[keithb7]

I ended up going with a totally different transmission oil option. I work at the local Caterpillar heavy equipment dealership. Cat has some pretty good engineers working with various oils over the past 100 years. I looked up what oil they recommended for old tranny's. Cat TDTO (transmission drivetrain oil) 50W. After doing some research, I bought a 1 gallon jug and thought I'd give it a try. Employee discount! So far so good. My tranny shifts great. The new synchro in mine feels great. I am very happy with the results. I am now quite confident that the GL-5 I was using, combined with the original, well worn synchro was 100% causing my synchro gear clashing. In addition to the tranny work and new oil, while I was in there I added a robust magnet. I placed it against the inside of the cast tranny housing in an area with good clearance from the gears. It will collect any ferrous wear material over the next 50 years.

 

Experience is a great thing...

 

Edited July 12, 2020 by keithb7

[Sam Buchanan]

7 hours ago, plymouthcranbrook said:

I had the rear transmission rear seal replaced recently and decided to go with the Redline fluid as a replacement. Haven’t driven it too much as of yet but so far shifting seems much improved. No longer have to shift slowly into second with a pause in neutral.  So far so good. 

 

I was watching an episode of 'Jay Leno's Garage' recently and Jay mentioned that even though he is no fan of "repairs in a bottle" he found changing to Redline MTL in one of his cars fixed the balky shifting. 

[sidevalvepete]

On 5/29/2020 at 12:01 PM, keithb7 said:

After reading all of the great posts in this thread, I am thinking...Good chance my gear grinding with the synchromesh is related to the GL-5 oil I had in my '38 speed tranny. I did order a NOS synchromesh earlier in May here. It was a decent price at $80, but I sure am losing a ton of primetime driving, while I wait for it to arrive. It took 13 days to be shipped within in the CON USA, to E-bay's Global Shipping distribution centre in Kentucky. It left there yesterday. Brutal. It'll be another 7-10 days before I see it here at my home in Canada. Meanwhile I am staring at my disassembled tranny here. Could be ready to go,  with proper oil this time,  if I re-use the old synchro. The days just keep passing by. I am really tempted to just put it back together with the old synchro and see how it runs with the right oil in it. Damn Ebay and their global shipping program. I'm almost out of patience. 

I hear you about the freight delay. I have had a number of transactions with Bernbaums over the years and had good service then my last small package got flipped out of the standard postal system and put on sea freight. Took seven weeks to arrive. No fault of Bernbaums, just the disruption from the covid thing. Hope you all stay safe and healthy out there.