What kind of damage will I do to my NV5600

[Cattletrkr]

... by running a regular 50w synthetic manual transmission fluid in it? Mine has been leaking ever since the rebuild went in and tonight it was about 0. 5qt low, from factory level. I added about 1. 5qts of Mobil 50w synthetic transmission fluid to the Penzoil synchromesh that's already in there. I've used it before with no probs. The only time I changed the fluid in my '01 I put that stuff in there and had no probs in the 30K I put on it before I sold it.

 

[Gary - K7GLD]

I suspect it all really hinges upon shifting quality - as far as lube quality, the 50 wt. is probably just fine...

 

[Duluth Diesel]

Well, I'd stick with a recommended fluid. I run AMSOIL MTF in my NV5600, which meet the 5W30 Synchromesh specs for this transmission.

 

[Gary - K7GLD]

Well, I'd stick with a recommended fluid. I run AMSOIL MTF in my NV5600, which meet the 5W30 Synchromesh specs for this transmission.

Is the Amsoil Syncromesh spec the same as, or meet the DC 9224 spec?

 

[Duluth Diesel]

Yes it does, Gary.



Specifications

• GM 9985648

• GM 9986105

• GM 9985535

• Chrysler MS-9224

• Chrysler MS-9417



Info here: https://www.amsoil.com/storefront/mtf.aspx?zo=1206252

 

[Gary - K7GLD]

Yes it does, Gary.



Specifications

• GM 9985648

• GM 9986105

• GM 9985535

• Chrysler MS-9224

• Chrysler MS-9417



Info here: https://www.amsoil.com/storefront/mtf.aspx?zo=1206252

That's good news - thanks!

 

[steved]

5w30 motor oil is roughly a 70w90 weight gear lube weight... a 15w40 motor oil is roughly a 80w90 weight.

I'd worry about two things: incompatibility of oils and shifting quality.

steved

 

[Cattletrkr]

5w30 motor oil is roughly a 70w90 weight gear lube weight... a 15w40 motor oil is roughly a 80w90 weight.

I'd worry about two things: incompatibility of oils and shifting quality.

steved

In English please. :-laf

 

[NIsaacs]

Not to worry, it was low, right? Anything is better then none



I have always said, pickup manufactures are using lighter and lighter weight oils in the trannys. Is this to save fuel or cuz it is best for the transmission?



I think the G-56 uses ATF? On the Freightliner medium dutys, they use MB manual transmissions with 50 weight synthetic. They look very simular to the G-56 and weigh 300 lbs dry. Are they the same transmission?



I would say that the 50 weight Mobil you used in your NV5600 would be even better then the factory fill.





"NICK"

 

[steved]

In English please. :-laf

5w30 is the weight of a typical Synchromesh, which is equivalent to a 70w90 gear oil. Since you are using a "lighter" 50W, than a typical synchromesh, it might work well if the syncronizers don't mind it and the other fluid doesn't react with it.



I wonder how bad running that "light" of fluid would actually be... since the G56 uses ATF... in regards to the protection the 50W will afford versus the slightly heavier synchromesh??



steved

 

[Cattletrkr]

5w30 is the weight of a typical Synchromesh, which is equivalent to a 70w90 gear oil. Since you are using a "lighter" 50W, than a typical synchromesh, it might work well if the syncronizers don't mind it and the other fluid doesn't react with it.

I wonder how bad running that "light" of fluid would actually be... since the G56 uses ATF... in regards to the protection the 50W will afford versus the slightly heavier synchromesh??

steved

Where did you hear that? A 5w-30 is nowheres near as thick as any gear oil. A simple pour from the bottle will show that. The 50w that I put in there is much much much thicker than the Penzoil Synchromesh that was in there.


Nick,

I bought the 50w to put it into my '01. Later, when I wanted to put it into the '04, I found out it's not made for synchros. It never caused any probs with the '01, but the '04 was under warranty at the time so I went with factory fill. I agree the transmission should be able to handle the 50w, but the synchros are what I'm more worried about. I've heard of some weird combos veing run in theses trannies with no probs, but I've never heard of anyone trying what I am.

Now I wish I had a temp gauge so I could see if there's anything going on there.

 

[NIsaacs]

I think what "steved" is saying, is that the new transmission oils will compare to the old style gear oils. Not in a physical way but in the performance/technical specs. I don't understand it all myself.



However it is hard for me to understand how oils as thick as water can protect metal to metal contact under heavy torque and high heat. To me it stands to reason that a medium duty truck transmission uses a heavier "physically" oil than ATF?





"NICK"

 

[Duluth Diesel]

All these transmissions spec a certain fluid for a reason. Whether it be the G56 needing ATF, the NV5600 needing 5W30 Synchromesh, or the NV4500 needing a Manual Transmission and Transaxle Gear Lube 75W-90 API GL-4.



Depending on the composition of the synchro material in the transmission, different fluids are needed. Putting 75W90 in a G56 trans will cause problems, as would putting ATF in an NV5600 or NV4500. I recommend that you stick to the specifications for the transmission. If you aren't happy with one brand, then try another brand of the same spec fluid.



-Chuck

 

[steved]

Where did you hear that? A 5w-30 is nowheres near as thick as any gear oil. A simple pour from the bottle will show that. The 50w that I put in there is much much much thicker than the Penzoil Synchromesh that was in there.

5w30 motor oil "weight" is equivalent to a 70w90 gear oil "weight"... just like a 15w40 motor oil is equivalent to a 80w90 gear oil. A 70w90 gear oil is actually quite thin... Redline MTL (the "synchromesh" equivalent) is a 70w90 transmission fluid.



Best of luck,

steved