Manual Transmission Gear Oil - 85 Nissan 720

[Wildcat Walker]

That Valvoline is NOT a GL-4 oil. GL-4 is difficult to find stocked in part stores these days. Synchronesh may work in a pinch. Royal Purple may still make a GL-4 product. Sta-Lube has a few products, and Redline Oils as well. Chevron TH1000 is also a suitable GL-4 fluid. 

[KELMO]

FWIW, your local Nissan dealer may carry the correct gear oil as well.

999MP-MTF00NP 75W-85 and I believe it states on the bottle GL-4.*

 

 

 

*This is from memory, I have not worked in a Nissan parts department for almost 2 years.

 

 

[Meesh]

I did the gear box oil change and some pretty large (some about 1”) pieces of metal came out 😭 click here to see 

 

I don’t know the last time it was changed though… thinking about changing it in a few months just to check and see if there’s any more pieces that come out and how much metal the magnetic drain plug catches. 
 

The transmission does sound better and the gear shifts a bit smoother. 
 

I do have a question though… I filled the gear box when it was up on jack stands… Is filling it to the top while in that position going to be enough? Or should I add more while the truck is level? 

[Meesh]

On 7/21/2023 at 5:26 AM, Wildcat Walker said:

That Valvoline is NOT a GL-4 oil. GL-4 is difficult to find stocked in part stores these days. Synchronesh may work in a pinch. Royal Purple may still make a GL-4 product. Sta-Lube has a few products, and Redline Oils as well. Chevron TH1000 is also a suitable GL-4 fluid. 

oh shit, alright. I guess another gearbox oil change is in order 😭

[Meesh]

On 7/18/2023 at 10:09 AM, datzenmike said:

 

Can't see where it says it's GL-4 on the bottle. GL-5 has 50% more anti scuff additives in it than transmission GL-4. The anti scuff additives are sulphur based and break down and become acidic which is fine in a differential which contains no copper/brass parts but is bad for brass synchros in transmissions. Any gear oil that says it's good for transmissions and differentials is somewhat suspect.

 

I believe all synthetic transmission oils come from the same stock and maker. A dye is added for the seller.

 

Front R-180 differential ........... 1 liter 2 1/8 US pints.

 

Rear H-190 differential.............. 1.25 liter 2 5/8 US pints

I’ve heard that it’s better to go with conventional oils rather than synthetic, is this true? 
 

I was only planning on using the valvoline for the gearbox and grabbing a different bottle for the differentials, but now I’m worried it’s going to mess up the trans…. 😫😫😫

[datzenmike]

Can't see those metal pieces, picture way too small and on f/b. Usually it the front counter bearing race falls apart.. not at all good news.

 

Synthetic oils are great but it's thinner and slippery and may begin leaking past old seals. I run a synthetic because the shifting is much improved.

 

The wrong GL won't hurt anything in the short run it accumulates over time. Change at the end of the summer.

[Wildcat Walker]

19 hours ago, Meesh said:

oh shit, alright. I guess another gearbox oil change is in order 😭

I would say it is. The giveaway is that the container states that it meets GL-5 specification, which indicates that the oil has the additives that make it GL-5 (sulfur). Gear oil starts as a base oil and then additives make it a GL-1 then a 4, then a 5. It can be hard to find GL-4 in a part store, so save yourself the trouble and order some redline mt90 from summit racing. 

[datzenmike]

GL-4 has about 0.04% of the sulphur anti scuff additive. GL-5 is about 0.06%. Looks like 0.02% difference, what's the big deal right? In reality 0.06% is 50% more than 0.04% and that's big.

[Meesh]

 

@datzenmike

Edited August 4, 2023 by Meesh
Tag

[Meesh]

On 7/30/2023 at 5:50 AM, Wildcat Walker said:

I would say it is. The giveaway is that the container states that it meets GL-5 specification, which indicates that the oil has the additives that make it GL-5 (sulfur). Gear oil starts as a base oil and then additives make it a GL-1 then a 4, then a 5. It can be hard to find GL-4 in a part store, so save yourself the trouble and order some redline mt90 from summit racing. 

I got some Royal Purple that I’ll change it with at the end of summer like @datzenmike suggested 

[powderfinger]

I am guessing your transmission must be making a fairly loud grinding/whining noise when driving after seeing those pieces that came out of it.

[datzenmike]

9 hours ago, Meesh said:

 

@datzenmike

 

Looks very much like a ball bearing race. It holds and spaces the ball bearings. I have drained a transmission and the balls fell out before.

 

[Stoffregen Motorsports]

I have been using Redline MT-90 in all my manual transmissions for the past 15 years or so. I don't buy into the theory that it will make your trans leak. All modern oils use the same film thickness technology and would all be more likely to leak than the old thick molasses they used to use.

[datzenmike]

Old seals then. My transfer case began to leak front and back. Changed them and it was fine. My differential pinion seal. A couple of my 71B rear transmission seals. They were fine till I changed to synthetic. Oh, the front crankcase seal on the timing cover became wet after throwing a quart of synthetic engine oil in. Next oil change went back to regular syrup and it dried up.

[powderfinger]

4 hours ago, datzenmike said:

Looks very much like a ball bearing race. It holds and spaces the ball bearings. I have drained a transmission and the balls fell out before.

Yep, had the same thing happen to a transmission in one of my 720 trucks.

[Meesh]

On 8/4/2023 at 4:57 AM, powderfinger said:

I am guessing your transmission must be making a fairly loud grinding/whining noise when driving after seeing those pieces that came out of it.

It grinds a bit when I’m in higher gears at too low of an rpm but other than that I haven’t noticed any whining noises. How soon do you guys think I’ll have to go in and replace This… ball bearing race? 

[datzenmike]

It can only grind (gears) when shifting. What you call grinding may be growling from the bearing?

 

Well if the balls are not supported properly it can go south rather suddenly if the balls fall out. They're not meant to be ground up in the moving gears. It's probably not the front counter bearing because they are commonly the loudest. They make noise in every gear but 4th. I guess if driving and there is a sudden change stop driving it.

[Meesh]

I think I jinxed myself…truck started making some bad noises while on a delivery for a client. I’m really really hoping 🤞🏻 it’s not a knock that I’m hearing. 
 

I should probably just fix it before it becomes an issue. I think I’m going to park it for a little bit while I save up to get the parts needed. 
 

How difficult is it to get into the transmission? I’m probably going to have to pull the motor right? 

[datzenmike]

You can pull it with or without the engine.

[powderfinger]

11 hours ago, Meesh said:

How difficult is it to get into the transmission? I’m probably going to have to pull the motor right? 

The short transmissions in the 4x4 trucks are fairly easy to remove. The longer ones in the 2wd king cab trucks are a little more difficult just because the longer shaft wants to hit the floor of the truck when trying to get it out. Make sure you pull the carpet back and remove the cover around the shifter that is attached with 4 screws I believe. This will give the tail shaft of the transmission enough room to allow the transmission to easily be removed.

 

No need to remove engine.