Transmission Fluid, ???? Options

[mxhondarider832]

I have a '74 914 and the transmission is a little leaky and need to change the fluid, the book says to use straight 90w oil but I am having a really tough time finding it so I was wondering if there was a newer substitute that I could use. This is my first 914 and I am struggling a little bit and could use some help thanks

[SirAndy]

Swepco 201 is expensive and the Cap'n will tell you it's no good but i've been running it for years with very good results.

It made a noticeable improvement in shifting from whatever the PO had used. Transmission oil is not really a "wear" item, which makes it easier to justify the extra expense for Swepco.

I cleaned up and re-sealed my 901 about two years ago and it's still bone dry.
(IMG:style_emoticons/default/stirthepot.gif) Andy

PS: (IMG:style_emoticons/default/welcome.png)

[Richard Casto]

Transmission oil is not really a "wear" item, which makes it easier to justify the extra expense for Swepco.

Yes and no. Transmission oil doesn't live as hard of a life as engine oil, but I would put it firmly in the "wear item" or "needs to be replaced" category. Stuff can get inside (such as via the breather vent) and periodic replacement can flush that stuff out. Also, the oils have additives (particular such as the EP - Extreme Pressure) that do not last indefinitely. Not that you said it, my concern is I don't want new owners to think transmission fluid is a "never change" item. It does have a service schedule.

Redline oil is actually contraindicated in our gearboxes (hypoid gears).

I know why you are saying this, can almost agree, but don't agree. Redline does have a GL-5 transmission fluid that should be fine in our transmission. I haven't used it, so I can't say how well it works. Even your other post above with the text from the Redline site does says which of their fluids to use in our transmission.

What concerns me about Redline is that it's really easy to buy the wrong fluid from them. I see lots of comments about "Redline MT Fluid". Are they using "MT" as a generic term for "Manual Transmission" fluid or the specific "MT/MTL" product line from Redline? The specific "MT/MTL" line of fluids from Redline is GL-4 ("4" not "5") and should NOT be used in a 901/914 transmission. As you say above it is not GL-5 and is not compatible with hypoid designs. So we can agree on that. Specifically the following from Redline should NOT be used in a 901/914

* Red Line MT-90 GL-4 (Not GL-5 spec)
* Red Line MT-80 GL-4 (Not GL-5 spec)
* Red Line MTL GL-4 (Not GL-5 spec)

But Redline does have two GL-5 products. BUT of their two GL-5 fluids, one has a lot of friction modifiers and even on their site says that it should NOT be used in transaxles (combo transmission with synchros and a differential). That due to the friction modifiers you may experience bad shift quality. In short that fluid should also NOT be used in a 901/914 transmission. The second one however does look to fit the bill. Basically you really have to read all of the fine print to zero in on that one single product out of a small sea of manual transmission fluids from them. That one Redline fluid that should work is "75W90 NS GL-5 Gear Oil". The three things to note are...

* "75W90". The viscosity is not 80W90, but probably is fine
* "NS". This is the version that has less friction modifiers so it is more compatible with our synchro design.
* "GL-5". It is GL-5 spec and works with hypoid gears.

Here is a direct link on thier site...

http://www.redlineoil.com/product.aspx?pid=47&pcid=7

Now because it is so easy to buy the wrong thing from them I can understand the "Don't buy Redline" stance. Even then, someone may use the right stuff from them and still report problems (such as the other thread in which Swepco is not working well for one guy), or it might work great for them. As always, your mileage may vary!

On top of all of that, I put Redline in the "boutique" category just like Swepco. Which again may or may not add any real value. I probably wouldn't buy it personally and would just buy good quality GL-5 dino oil from one of the regular mainstream vendors (Valvoline, Castrol, etc.).

Lastly, here is my article on transmission fluid...

http://www.blueskymotorsports.com/index.ph...16&Itemid=6

Richard