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I have been thinking about using Royal Purple. Does anybody use this and what are there opinions of it?
 

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i use all royal purple fluids on my 97 240sx. I love the stuff, it shifts smother, i get slightly better mileage, and it accelerated alittle quicker to 60 after doing the swap. Of course the last two probably had more to do w/ swapping engine transmission and rear diff all at once. I recommend it.
 

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Discussion Starter · #7 ·
Thanks to NSANY for getting this information together.

This is some useful and VERY important information regarding transmission fluids.

A friend and I were talking about the recurring noise I have in my Pathfinder's manual trans. Basically, it's most noticeable when the trans is cold, or sometimes when shifting between 1st and 2nd or 2nd and 3rd. (sound kinda like that same problem some people have had with their Z's doesn't it?)

So, I did what I always do -- I did research.

Turns out that 99.9% of all "gear oil" sold in stores is API GL-5. Problem is, the factory spec for my Pathy is GL-4. Common logic would say, "Isn't GL-5 BETTER than GL-4?"

More research, please...

So I did some Google Group searches. (By far the best way to get instant info on the internet). Turns out that GL-5 includes some additives which are harsh on yellow metals (brass included) and can cause premature corrosion or breakage of bushings and synchros in your trans. Moral of the story, GL-4 is very different from GL-5, and if your spec calls for GL-4, you'd be well served to follow the manufacturer's advice. (Listen up, folks! The 350Z also calls for GL-4 gear oil!)

So all this had me wondering -- could it be that some 350Z owners have unknowingly replaced their gear oil with GL-5 and led to some premature problems? (I'm specifically thinking about folks who used Mobil 1 or other off-the-shelf synthetics -- most if not all of them are GL-5).

Just doing my part to look out for the troops -- if you've done an oil change on your MT, be sure to find out what type of oil was used, and if you have GL-5, GET IT OUT OF THERE!

Redline oils makes a GL-4 which I'll be looking for tomorrow for my Pathfinder. If any of you have done an oil swap on your trans, be sure to check what you used!


A quick follow-up after my recent junket in search of GL-4 gear oil:

1. None of the major oil manufacturers make GL-4 (by this, I mean Mobil, Valvoline, Quaker State, Pennzoil, etc.) All of them sell GL-5, which "exceeds the GL-4 standard". That's fine, but the part they fail to realize is that the additives which make it exceed the GL-4 spec is exactly what ruins your trans...

2. In rare instances, you can find GL-4 from local auto parts stores, but it's always a one-off brand that I wouldn't trust.

3. This whole experience would be a lot less painful if we could use GL-5 gear oil.

4. Redline's web site sucks. They need to include a database of local resellers sortable by ZIP code. The list they have stinks.

5. Summit Racing sells the entire suite of Redline products, AND they only charge $7.95 flat rate for shipping. Combine that with no tax, and you have a GREAT deal. I have a pile of stuff coming hopefully in time for the weekend.

Report to follow after the change of fluids...

In the meantime, a few more pieces of corroborating evidence supporting the theory that GL-5 will ruin Nissan trannys:

http://groups.google.com/groups?q=n...&oe=UTF-8&hl=en

http://www.nissanoffroad.net/messag...p?TOPIC_ID=4097
 

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SWEET! I am doing a tranny fluid swap this weekend and this information is great. Granted, I was planning on using the Redline MTL/MT-90 blend that others recommend. So, I would have been safe no matter what.

I have a 2003 and thankfully I have had no issues. I guess using GL-4 will help to keep it that way.
 

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Depends on where you use it.

For the tranny, you MUST use a GL-4 specification oil because the tranny has yellow metals (brass, etc) in it. GL-5 can ruin it. Most RedLine oils are GL-4, but not all. Mobil 75w-90 synthetic is definitely GL-5.

I used Mobil 1 75w-90 in my differential because it has no yellow metals. Just this past weekend, I switched my tranny to a 50/50 mixture of Redline MTL and MT-90. Both of these oils are GL-4 compliant.

Checkout Redlineoil.com for complete information on the specifications and weights.
 

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Aloha,
Redline MTL and MT-90 Transmission oils are GL-4. Redline 75W-90 gear oil is
GL-5 / GL-6.
Just about all other Manual Transmission oils are GL-5.

A Hui Hou

PaulO
 

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This post was a real live saver!!!

I was about to have Castrol Synthetic put in my Tran when I read this, so I called Castrol.

Castrol stated that the higher level of additives in the GL-5 gear oil will in fact attack the brass syncros in transmissions.

Castrol stated that PL-5 is definetly NOT backward compatible to GL-4.

This really makes me wonder about Nissan.

What are they doing designing/manufacturing atransmission which requires a lubricant which is no longer produced by any of the major oil companies?


I will have my transmission oil replaced by Nissan, with their oil, to insure that they will honor the drivetrain warranty.

I am not taking any chance they could claim problems are caused by anyone elses oil.
 
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