Manual Transmission Fluid

[310GX]

I have a 1981 Datsun 310 GX. I have replaced the 4 speed with a dogleg 5 speed. Thanks for the help in getting it shifting right. It was the linkage that was messing everything up. I now have a new problem. It was leaking the fluid out of the manual transmission. I want to replace the fluid and seal it up. I know it holds 2.3 liters. The Datsun service manual does not say what the correct fluid should be. It does say in the troubleshooting section that if the transmission is noisy that one of the reasons could be the wrong fluid was used. It does not say what the correct fluid is. Does anyone know what fluid is supposed to be in the transmission?

 

 

[datzenmike]

GL-4 80-W-90. This is what Nissan recommends. Don't let someone from an auto parts, dealer or where ever you buy oil try to tell you that GL-5 is the same, or better, or and up grade. These trannys are older and have brass synchros in them that will be attacked by the higher anti scuffing sulphur compounds present in GL-5 gear. GL-5 is just fine in differentials. Some newer cars use steel synchros so GL-5 can be used and this is where the confusion begins.

 

You can also switch to a good synthetic if you are rebuilding it. Old seals/gaskets tend to leak synthetic oil because it is so slippery.

[Hurley]

What about rear end fluid? Is a different fluid needed?

[datzenmike]

GL-5 is just fine in differentials.

 

You can also opt for a good synthetic for the diff also. As with trannys it can leak past the pinion seal if old or worn.

[HRH]

Royal Purple gear oil is still a GL4 rating. So is Red Line. Ditto GL5 eating synchros. Here's a question Mike, when transmissions are rebuilt new, do the rebuild kits come with brass synchros, or are they a different material? Anyone know?

 

I'm wondering what fluid I used in the dogleg in the 510 after I had it rebuilt. Think it was just regular Valvoline gear oil and I can't remember. I may want to change it I think.

[ppeters914]

IIRC, the Vdub folks (and those transaxles -HATE-HATE-HATE- GL5) say NAPA has a GL4-friendly oil.

[datsunaholic]

Not all GL-4 oils are the same. You HAVE TO check to make sure the bottle is marked "yellow metal safe". Some GL-4 are not safe. The Phosphor Bronze synchros cannot handle most GL-5 oils, and GL-5 should never be used in a transmission anyway.

[ppeters914]

Not all GL-4 oils are the same. You HAVE TO check to make sure the bottle is marked "yellow metal safe". Some GL-4 are not safe. The Phosphor Bronze synchros cannot handle most GL-5 oils, and GL-5 should never be used in a transmission anyway.

Agreed. Here's the link:

 

Gear Oil Selection

 

I may have used Sta-Lube. Don't remember (it was almost a year ago) and didn't save the bottles.

[datzenmike]

The factory parts would be, I guess the kits would be.

 

Who but me would have one on their computer desk?

[Braden]

Agreed. Here's the link:

 

Gear Oil Selection

 

I may have used Sta-Lube. Don't remember (it was almost a year ago) and didn't save the bottles.

awesome link man, i found some at anapa and at car quest, of course oreillys where i work sucks we dotn carry any of it and everybody there is ignorant and tried telling me i could run gl-5 they always give me hell and make fun of my datto, but i understand, if i was in my 30,s or 40,s and worked at an auto parts store and didnt have a datsun i would be pretty tore up too lmao!!!

[Braden]

i went with the redline gear oil, it is specifically designed for transmissions and is cheap compared to the royal purple scum, http://www.summitracing.com/parts/RED-50304

[inline4]

offtopic, but what gear oil should I use on the rear end?

[datzenmike]

Not really off topic. Minimum GL-5 is recommended for Nissan rears. There is no copper or brass in the diff so more anti scuff additives can be used.

[inline4]

how many quarts? I have half a quart of mobil 1 gl5 and a quart of redline gl5 :o

[datzenmike]

Less than two for sure. Fill until the oil runs out the filler hole.

[inline4]

mixing the two wont be a problem? and is 75/90 okay for the rear?

[MikeRL411]

The "correct" gear box lube really depends on the vehicle, its age and the climate. I owned a 1949 Mercury, wish I still had it, and the driver's manual was very specific. If you lived in Maine or Alaska the instructions were that in September you drained the manual transmission and scrubbed all gears with kerosene. "The amount of kerosene that clings to the gears is the proper lubricant for the transmission through the severe winter months".

[inline4]

i live in ca, soon to be san francisco

[Creepy Cruiser]

And what about for a KA trans? (since we're on the subject, lol)

[inline4]

And what about for a KA trans? (since we're on the subject, lol)

ka trans is 75w90 according to google.com

 

2.5quarts

[Creepy Cruiser]

Right, but what about the whole GL-4 vs GL-5 thing?

[datzenmike]

I can't find the original of the following:

 

What happens if API GL-5 gear oil is used in an API GL-4 gear oil application?

API GL-4 and API GL-5 products typically use the same extreme pressure (EP) additive system, with the API GL-5 having about twice the concentration of a API GL-4. In service, these additives become active under extreme load and temperature when the protective oil film can be squeezed away. EP additives work by forming wear-resistant compounds with the metal of the gear tooth surface. As the gears mesh, these compounds shield the gear teeth from direct metal-to-metal contact that would cause wear and damage to the gears. If too little of the active additive is present, proper protection would be compromised. Too much of this additive could cause excessive chemical corrosion of the gear surface. If an API GL-5 gear oil is used in a application where API GL-4 gear oil is called for, chemical corrosion of "yellow metal" components may occur, such as bronze synchronizers, brass bushings, etc. This may lead to shifting difficulties or shortened equipment life.

[End Quote]

 

So:

The lower concentration of sulphur additives in the GL-4 is friendly with the copper/phosphor bronze parts like synchro rings used in most Nissan trannys. Higher sulphur content GL-5 is good for differentials that contain no copper/bronze parts.

.

[Braden]

hey guys i recently drained my 4 speed and refilled it with the crc brand gl-4 yellow safe 80w-90 gear oil, im pretty sure the old oil was gl-5 put in by the po, that shit was blacker than black, before i changed it third gear would grind a bit when i wound out second and shifted, now its smooth as a babys ass, i didnt realize how big of a difference it makes!!!! i am going to be putting in my new engine and my 5 speed soon and i just wanted to kind of flush out the 4 speed before i stored it, if any of you have gl-5 or even if you have a gl-4 thats not yellow metal safe GET IT OUT!!!!!!!!!!! that shit will ruin your trans, dont go to a parts house and talk to anyone about it, they are all idiots, find it yourself so you know you have the right shit.

[datzenmike]

The oil should be similar just the amount of sulphur compounds is less in the GL-4. If it made that much difference maybe the p/o used something totally different... and totally wrong! Maybe it was low as well. My son's old Grand Am used engine oil in the tranny so you never know. Glad it's working.

[SRSANDS]

I have and used hypoy c castrol gl5 in my subi lsd and 300zx trans...am I safe? I didnt know gear oil was so technical