Superior tranny oil, Slight tranny sound....how to make go away? Options

[rjames]

When do you hear the noise? Is it worse at a given speed or in a certain gear? Does it change pitch? If yes, under what circumstances?
When the sound is present, does it go away when depressing the clutch or when putting it in neutral?

[second wind]

I am going to recheck on my next drive....really soon. I appreciate all the help. Front wheel bearings are fresh but I will check.....rears are old but have been fine....I may just be hearing the normal noise of the car functioning....I will really focus and report back....plus check level and switch to dino oil for sure....see what happens....thank you all very much.
gg

[SO.O.C914er]

I’m using valvoline high performance 75 - 90w gear oil. What do the 914 GODS think of this product. 64k on my tranny. Oh no I said tranny (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/chair.gif) someones going to jump on that!

[second wind]

I don't get it...please 'splain.....
gg

[second wind]

Hey!! I got it.....politically correct not......well......not everyone loves Porsches.....
gg

[90quattrocoupe]

And why is synthetic gear oil bad for a 914 trans?

Greg W.

[Dr Evil]

Below in my signature is a link to several pages of notes. I go over all of the answers to the questions asked, and the possible faults.

Short answer for oil, these boxes lasted 30+ years on neglect and dino oil. You really dont need to spend more and you will not get improvement. Simple GL5 80-90w is all the factory recommended and I use the cheap stuff. Synthetic tends to be too slippery and our boxes work on friction. Also, fancy oils tend to have fancy emulsifiers and detergent packages included with them. This is not necessary and can actually, in my opinion and experience, cause harm over time (read my notes for more details).

As for noise abatement:
IF your box is in good shape, just tired, you can substitute a qt of Lucas oil stabilizer. I use this for assembly lube on my builds because it is as thick as honey and stays on the bearings to assure that they are lubed from the first turn of the crank. This is the stuff they sell everywhere and has the cool little display with the gears showing the lube crawling up the gears v not doing so with the regular oil. Used in over a hundred builds and was actually a tip passed down to me from an experienced Porsche mechanic (which is why I was no hesitant to try it). It will get rid of high pitched whines due to wear over the decades. Also, keeps lube locked into the bearings which sit outside of the oil bath.
Eventually, though, you will need to open and inspect bearings and R/P health.

[rhodyguy]

Great bit of info re the Lucas.

[second wind]

Below in my signature is a link to several pages of notes. I go over all of the answers to the questions asked, and the possible faults.

Short answer for oil, these boxes lasted 30+ years on neglect and dino oil. You really dont need to spend more and you will not get improvement. Simple GL5 80-90w is all the factory recommended and I use the cheap stuff. Synthetic tends to be too slippery and our boxes work on friction. Also, fancy oils tend to have fancy emulsifiers and detergent packages included with them. This is not necessary and can actually, in my opinion and experience, cause harm over time (read my notes for more details).

As for noise abatement:
IF your box is in good shape, just tired, you can substitute a qt of Lucas oil stabilizer. I use this for assembly lube on my builds because it is as thick as honey and stays on the bearings to assure that they are lubed from the first turn of the crank. This is the stuff they sell everywhere and has the cool little display with the gears showing the lube crawling up the gears v not doing so with the regular oil. Used in over a hundred builds and was actually a tip passed down to me from an experienced Porsche mechanic (which is why I was no hesitant to try it). It will get rid of high pitched whines due to wear over the decades. Also, keeps lube locked into the bearings which sit outside of the oil bath.
Eventually, though, you will need to open and inspect bearings and R/P health.

Ok.....I bought two quarts of simple GL-5 80-90w amd a quart of the secret ingredient Lucas Oil Conditioner. Why does it say "for use in non-synchronized manual transmissions" on the back? Aren't 901 transmissions synchronized? What up with this statement? I know this is typical 914 'er over thinking....but I like it. Do tell...thank you very much.
gg

[second wind]

On the back of the Valvoline oil that is....
gg

[Dr Evil]

On the back of the Valvoline oil that is....
gg

Dunno. Keep in mind that the oils you buy now are not considering the intricacies of a 40yo Porsche transmission when making blanket statements. You will see that GL5 is also not recommended for transmissions with "yellow metal" in them, which ours clearly are, and GL4 is the preferred. The GL refers to the detergent and other additive package in there. The GL5 can stain the yellow metals of the shift forks and bearing housings, but this is not an issue in operation and the engineers at Porsche were well aware of this. As long as you stick to the weight, GL5, and no funny additives, you will be fine. It is when people try to outsmart the engineers and use really slippery stuff that their boxes get destroyed. I had one recently and I swear he used 10w as it was like water, clear, and smelled like fork oil. His box would not select a gear and this was why.

[second wind]

On the back of the Valvoline oil that is....
gg

Dunno. Keep in mind that the oils you buy now are not considering the intricacies of a 40yo Porsche transmission when making blanket statements. You will see that GL5 is also not recommended for transmissions with "yellow metal" in them, which ours clearly are, and GL4 is the preferred. The GL refers to the detergent and other additive package in there. The GL5 can stain the yellow metals of the shift forks and bearing housings, but this is not an issue in operation and the engineers at Porsche were well aware of this. As long as you stick to the weight, GL5, and no funny additives, you will be fine. It is when people try to outsmart the engineers and use really slippery stuff that their boxes get destroyed. I had one recently and I swear he used 10w as it was like water, clear, and smelled like fork oil. His box would not select a gear and this was why.

Thank you very much Dr. Evil....I am going to put in one quart 80-90 and then the quart of Lucas, then top off with more oil. Does that sound right? I was going to flush the tranny with starting fluid or something that evaporates fast just to get a fresh start.....you ok with that idea? Thank you again,
gg

[Dr Evil]

On the back of the Valvoline oil that is....
gg

Dunno. Keep in mind that the oils you buy now are not considering the intricacies of a 40yo Porsche transmission when making blanket statements. You will see that GL5 is also not recommended for transmissions with "yellow metal" in them, which ours clearly are, and GL4 is the preferred. The GL refers to the detergent and other additive package in there. The GL5 can stain the yellow metals of the shift forks and bearing housings, but this is not an issue in operation and the engineers at Porsche were well aware of this. As long as you stick to the weight, GL5, and no funny additives, you will be fine. It is when people try to outsmart the engineers and use really slippery stuff that their boxes get destroyed. I had one recently and I swear he used 10w as it was like water, clear, and smelled like fork oil. His box would not select a gear and this was why.

Thank you very much Dr. Evil....I am going to put in one quart 80-90 and then the quart of Lucas, then top off with more oil. Does that sound right? I was going to flush the tranny with starting fluid or something that evaporates fast just to get a fresh start.....you ok with that idea? Thank you again,
gg

Your oil, yes. Your starting fluid, no. Stop trying to get fancy.

[second wind]

Point taken.....thank you again...will report back....
gg

[second wind]

There are hundreds of additive products on the shelf at your local FLAPS that will try to convince you that they will fix all sorts of problems.

Truth is, just make sure your tranny oil level is right, maybe even change it (especially if you are not certain that GL5 is in there). Anything beyond that and it needs some maintenance, not a magic BS treatment.

Hello Rand.....you were right...my tranny oil level was definitely low.....about an inch at least.....this time I will get enough in....and the good stuff....thank you very much.
gg

[Dr Evil]

There are hundreds of additive products on the shelf at your local FLAPS that will try to convince you that they will fix all sorts of problems.

Truth is, just make sure your tranny oil level is right, maybe even change it (especially if you are not certain that GL5 is in there). Anything beyond that and it needs some maintenance, not a magic BS treatment.

Hello Rand.....you were right...my tranny oil level was definitely low.....about an inch at least.....this time I will get enough in....and the good stuff....thank you very much.
gg

Looking forward to a positive report. (IMG:style_emoticons/default/beer.gif)

[Chi-town]

I always love the "Don't use synthetic!" comments with no actual data to back it up.

I've been rebuilding manual transmissions for close to 25 years now and I have not seen one actual test done to prove that statement. (If you bring up Bob the oil guy, go sit in the corner because the internet has beaten you)

I see all kinds of opinion statements like:
"It's too slippery"
"It's not compatible with old style syncro baulk rings / dog rings / blocker rings"
"It doesn't protect the bearings as well"
"The final drive will wear faster"

There are dozens of different formulations of synthetic gear lube just like there are dozens of formulas of organic gear lube.

While one may not work for your application, another may be way better than the organic oil you're running now.

If you want to see how your gear oil is holding up and what kind of wear materials are in it send it to Blackstone Labs. This will tell you the real story of what's going on with your oil. (works for engine oil also!)

When choosing a gear oil you need to look at how and what they are made with.
Base stock (Most synthetics here in the US use an organic base stock as you only have to be a % to legally be called synthetic)
Additive package (friction modifiers / stabilizers / sub stock)
Certifications / Compatibility per gearbox manufacturer

Lucas oil stabilizer is essentially a heavy additive package to try and fortify a standard oil. It works but in the end it is just a band-aid if you have a mechanical issue.

I've had very good results with synthetic in everything from Saginaw 3 speeds to Getrag 6 speeds. My go to is usually Motul Gear 300 unless there is a plated LSD internally then it's Motul Comp Gear. I use it because most of the cars I build see extended run time whether it's on the track or LA rush hour traffic where cooling is always an issue. In my testing and oil analysis samples the synthetic doesn't breakdown as fast due to heat as the organic oils I've tested.

That being said neither type will fix excessive wear or damaged parts.

Oh, and if you're whining about the cost of good gear oil, think about how much a trans rebuild is going to cost you. (IMG:style_emoticons/default/idea.gif)

[porschetub]

Sure the good doctor is right as he is referring to the 914 trans which he must know' better than anybody,so whats the secret to Swepco ? which the 911 guys all say improves shifting ,etc in those transmissions,no one seems to mention use in the 914 box that I thought was rather similar in design (IMG:style_emoticons/default/confused24.gif) .
Oil samples can't always be trusted ,last large vessel I ran had a massive gearbox failure due to worn out thrust bearing ,a recent oil sample showed no elevated levels of the bearing material in the oil,end result was a 6 month layup and around 1 million to rebuild it.

[mepstein]

Sure the good doctor is right as he is referring to the 914 trans which he must know' better than anybody,so whats the secret to Swepco ? which the 911 guys all say improves shifting ,etc in those transmissions,no one seems to mention use in the 914 box that I thought was rather similar in design (IMG:style_emoticons/default/confused24.gif) .
Oil samples can't always be trusted ,last large vessel I ran had a massive gearbox failure due to worn out thrust bearing ,a recent oil sample showed no elevated levels of the bearing material in the oil,end result was a 6 month layup and around 1 million to rebuild it.

Our guys have rebuilt dozens of 915 boxes and only use the GL4 80-90 dino oil.

[Chi-town]

Sure the good doctor is right as he is referring to the 914 trans which he must know' better than anybody,so whats the secret to Swepco ? which the 911 guys all say improves shifting ,etc in those transmissions,no one seems to mention use in the 914 box that I thought was rather similar in design (IMG:style_emoticons/default/confused24.gif) .
Oil samples can't always be trusted ,last large vessel I ran had a massive gearbox failure due to worn out thrust bearing ,a recent oil sample showed no elevated levels of the bearing material in the oil,end result was a 6 month layup and around 1 million to rebuild it.

Our guys have rebuilt dozens of 915 boxes and only use the GL4 80-90 dino oil.

Some data is better than no data. If you do an analysis on a regular basis you should have seen something.

There is no secret to Swepco, I've run it and it's a good oil just super expensive for anything but race cars.

@mepstein have you tried Motul?