Will92

Hi everyone:

I used to post here years and years ago and am pleased to see the site is still in operation. I can't believe Daniel B. Martin is still around too! He helped me out with several questions years and years ago.

I am the original owner of a 95 Maxima SE with MT. The car is in near mint condition with only 63k miles since I have always had a short commute. When I recently looked at new cars, I have a greater appreciation for the fit and finish of this old car that is probably only worth 3-4k but would cost 20k+ for an equivalent replacement!

Now to my question. I would like to have the MT fluid changed by my mechanic at my favorite Nissan dealership, I am a bit bewildered by the choices and it seems the only choice at the dealership is Quaker State (I think) and I don't know if it is synthetic or not.

I have researched this topic a bit and understand first of all it is very important to use the GL4 gear oil specified for our cars and not GL5.

My questions are:
1. should I use a synthetic transmission oil or try to find a mineral oil (since I'm fairly sure a mineral oil was the factory fill in our cars).
2. my FSM specifies 80-90W oil but all I have found is 75-90, does it matter?
3. I have found Amsoil, Redline and Pennzoil, all offering synthetic 75-90 in GL4. Are any of these brands favored by the board? I'm inclined to go with Pennzoil since they have been around for a long time but Amsoil and Redline are only available from select stores or internet sites although I must say I was impressed with the articles I found on Redline about synchronizer considerations, etc.

Thanks in advance for any advice as to which MT oil I should choose.

Daniel VQ30life

iTrader: (2)

buy the 75-90 from the dealership, it's almost penny for penny the same cost as royal purple etc.. drain and fill

JSutter

iTrader: (46)

I don't think Pennzoil makes a GL-4 only lube anymore. I'm not sure of many GL-4 only lubes available from the parts stores. Anything that is GL-5 should be avoided as it has sulphur can wear brass or bronze.


I have used Redline MT90 75w-90 (sometimes mixed with MTL 75w-85), Amsoil MTG 75w-90, both with great results. I like them equally, it just depends where I'm at when I buy more.

Years ago I also used Sta-lube hypoid GL-4 85w-90, but it seems to pour thick and slow which might cause stiff shifting in the cold.

Nealoc187

iTrader: (23)

DBM has been gone for over a decade probably. someone just happened to bump an old thread that had his name in the title.

gear oil isn't mineral based. unless you're racing the car, whatever GL4 you choose will be fine. if you're comfortable with the pennzoil brand then get that. i run redline, it's a good oil. weight doesn't really make a whole lot of difference again unless you are putting abnormal loads on the car (racing, lots of extra torque through engine mods, etc). anything in the 75-90 range will be fine, though the heavier stuff might feel a little stiff when it's extremely cold. my trans is a bit stiff for the first few minutes when it's below about 10 degrees F with 75w90 in it.

Daniel VQ30life

iTrader: (2)

mine is stiff in the cold also, i usually don't start driving tho until the heat comes on, so i don't run into that problem often

martyl45

Nice you have 4k more miles than my 95 GLE.

Will92

Thanks everyone. So does gear oil follow a different temperature chart than motor oil? I looked the chart in my FSM that 75W-90 and 80W-90 both protect to below negative 20C but you would use 5W 30 to protect engines at that same low temperature. Can someone explain this to me?

The FSM says "80W-90 is preferable for ambient temperatures below 40C".

I can't seem to locate GL4 in 80W-90, but 75W-90 and 80W-90 both protect to below negative 20C so they should both be suitable for winter driving, right?

Now here is where I am further confused. The chart shows an upper limit of 40C for the upper range of the 90 component. Doesn't transmission gear oil get hotter than this?


Here is a product from Pennzoil
http://www.pennzoil.com/other-car-pr...bricant/#About
http://www.pennzoil.com/wp-content/u...4+GL-5+ALL.pdf

I notice it says in the pdf that it is compatible with soft metals and copper alloys found in synchronizers. This is our type of manual transmission, right?
Thanks folks!

dwapenyi

iTrader: (3)

I think you may be over-thinking things. The main purpose of gear oil in a manual tranny is lubrication, unlike automatic tranny fluid or motor oil. If it's GL4, you're good to go

Also, I would be wary about going to the dealer. Nowadays there seems to be more GL5 fluid than GL4 prevalent. A lazy technician might accidentally put GL5 in your car because "it's whats on the shelf at the Nissan Dealership, so it must be right," mentality.

cashoit

Im running GL4 synthetic FWIW

Nealoc187

iTrader: (23)

yes they use different weight scales, and yes the trans oil will get much hotter than 40C.

that pennzoil would work fine, it is GL4 oil.