What is a Hypoid Gear?

[chitowndad]

I was just about to hit the submit button to pickup 3 qts of RedLine MT90 when I read that it said not to be used on Hypoid Gear Transmission, what the heck is that?

Here's the text "MTL, MT-85 & MT-90 are not for use in differentials with hypoid gears"

here's the link on the MT90 specs
Gear Oil and Transmission Lube - Red Line Oil MT-90 Manual Transmission Lube

any insight is appreciated.

Thanks,
-Steve

[landrovered]

Hypoid gears are differential gears where the pinion is not centered on the ring gear. The hypoid configuration allows for a higher clearance from a centered ring and pinion arrangement by shifting the ring gear axis up (or down) one side of the ring gear.



The reason that special oil is used on hypoid gears is because of the amount of shear. Hypoid gears need friction additives to compensate for the hypoid arrangement which would not work well with a Porsche synchronizer since the porsche gearbox and differential share the same fluid and are not hypoid.

[chitowndad]

Wow learn something new every day... Thinking I'm going with Royal Purple 75W90.

Thanks again,
-Steve

[landrovered]

I use Swepco, it is recommended for Porsche synchronizers.

Porsche RSWP201 swepco 201 TRANSMISSION gear FLUID oil; one (1) gallon

[JFP in PA]

Recommended by whom? Swepco?

[landrovered]

Originally Posted by JFP in PA

Recommended by whom? Swepco?

Auto Atlanta recommends it for all porsche manual gearboxes, Wayne R. Dempsey of Pelican Parts says "Use Swepco 201 transmission fluid for better shifting" here http://www.pelicanparts.com/techarticles/Boxster_Tech/38-TRANS-Manual_Fluid/38-TRANS-Manual_Fluid.htm

[JFP in PA]

Sorry, but I cannot agree. We spend way too much time draining just about everyone’s aftermarket gear oils out of these cars when the owners start complaining about "poor cold shifting", noise, etc.

Porsche uses a unique gear oil spec; we have inquired about alternatives from several of the "major" gear oil producers, who unlike the smaller blenders, openly admit (usually in writing) that they do not make a suitable substitute for the full synthetic stuff Porsche gets from Burmah (a very small manufacturer). Unfortunately, Burmah won't sell this product to anyone else, so we get it in drums from Porsche. Perhaps even more interesting is the fact that switching one of these cars back over to the OEM fill usually ends all the customer problems, unless permanent damage has already been done to the gear boxes……………….

Do some searching; we are not the only ones that have discovered this.........

[landrovered]

Dude, you basically just called the owner of this forum a liar.

It is not up to me to convince you I merely gave you two reputable Porsche firms that both recommend Swepco because you were acting like I was a dumbass.

[JFP in PA]

Actually, what I did was to disagree, based upon many years of servicing the transmissions in these cars, as well as a lot of dialog with other independent’s that also work on them. And no one that I am aware of called you anything.

[landrovered]

I appreciate your insight and will take it into consideration when I refill my gearbox but you did dismiss Swepco out of hand and I don't think that it deserves that because it is a viable product that is sold by reputable firms. That was my point.

[JFP in PA]

Again, no, I questioned the statement that it "is recommended" for Porsche gearboxes, and by whom. Far too many aftermarket lubricants are touted as "recommended" or worse, “approved” for certain applications that ultimately are found to come from the manufacturer’s marketing department rather then from actually meeting the specs. A perfect example is the number of engine oil sellers that state they have products that are "recommended" of cars requiring ACEA specs; then you check that statement out, you find that the producer's are not actually even members of the ACEA testing consortium, so their products cannot have ever even been tested, much less received any level of ACEA ratings approvals.

I strongly suggest that everyone should question "recommended" statements on all lubricants; you may be very surprised at what you discover................ . What I am positive of is that no Swepco product is on Porsche’s published list of approved gear oils for the car.

[Boxster33]

Hi, I changed my tranny fluid on my Boxster and used lubro moly 75w90 gear oil. So far no issues. Very smooth shifting. That being said I trust what JFP is saying, the only issue is that the Porsche fluid is difficult to get. The reason I went with Lubro Moly is because a Porsche Indy Shop said they used in all the Porsches they service. Will keep you posted if I have any ill effect going forward but so far so good.

[chitowndad]

Since the process is pretty simple, I'm going to try 3 quarts of Royal Purple at $13 per quart and if I don't like it I'll switch over to Porsche fluid at $28 per quart which is rediculous but it is what it is...

I once put RedLine MT90 and eventually MTL90 into my Nissan 300ZX and ended up putting in Royal Purple which I liked better... My Nissan had 100K miles without transmission service (lame previous owner) and MTL worked better than MT90 but Royal Purple was even better (quiter and less knotchy)

Thanks for all the advice. A local Porsche shop is like 1 hr. away...

-Steve

[jmatta]

Why would you even bother...to save $42? JFP has extensive history and experience, yet everyone keeps second guessing and trying to take the cheap route and will likely regret it in the long run; end up spending even more money than doing correctly the first time.

Just my opinion...

[landrovered]

Well what started out as a good thread has been reduced crap by a misunderstanding followed by an argument followed by intransigence followed by side taking and now declaration of guru status which negates the need for any further debate of the subject.

I see the web is working as well as ever.

[chitowndad]

I once asked my dad "why do you have 3 push brooms in the garage" and his response was

This one here is the $5 push broom that I bought because I was being cheap

This one is the $15 push broom that I bought when I realized that the $5 broom was a piece of crap

This one is the $30 push broom that I bought when I realized that sometimes you need to buy the best tool and I use it every day. The other brooms are there to remind me of my foolish ways.

So in my case, the $13/quart is all that the wife will allow at this point, when it doesn't work I'll spend $100 and do it right the second time.

LOL

-Steve

[chitowndad]

Replaced the tranny fluid with Royal Purple and it shifts really nice - if I experience any issues I'll post it here... Process wasn't that bad.

I also changed the oil and checked the filter - clean as a whistle!

Thanks,
-Steve

[chitowndad]

Ok, so back in October I put in some Royal Purple trans fluid and by December the shifting was really bad when it was cold. So I put the car away for the winter and took it out in March and replaced it with Porsche Trans Fluid. Now the shifting is normal when it's cold in Chicago, around 40's...

Only question that I have now is how do you know if you orer or under filled the transmission? I filled it up until it started spilling out. Is that correct?

Thansk,
-Steve

[JFP in PA]

Originally Posted by chitowndad

Ok, so back in October I put in some Royal Purple trans fluid and by December the shifting was really bad when it was cold. So I put the car away for the winter and took it out in March and replaced it with Porsche Trans Fluid. Now the shifting is normal when it's cold in Chicago, around 40's...

Only question that I have now is how do you know if you orer or under filled the transmission? I filled it up until it started spilling out. Is that correct?

Thansk,
-Steve

That is the correct fill level for the six speed.............and I won't even say "I told you so"............

[BYprodriver]

For Sale 3qts. of slightly used Swepco 201 (50 miles ) back in original gal container. Also For sale 1 new unused qt. Swepco 201.