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Posted by: StarBear May 14 2024, 09:10 AM

74 1.8 with original transmission.
What is the best fluid to use - either top off or replace? It now has a Swepco, though don’t recall which one (thought I wrote it in my notes but can’t find it).
A small seal leak, so like to top it off at the start of each driving season.

Posted by: nditiz1 May 14 2024, 09:14 AM

After Dr. Evils rebuild class I use 2 supertech (walmart) and a lucas gear oil.

Posted by: Superhawk996 May 14 2024, 10:19 AM

GL-5 rating is what matters.

Posted by: dr914@autoatlanta.com May 14 2024, 10:24 AM

80/90. years ago quaker oil made a special vw/porsche lube we used to put in all of our air cooled Porsche transaxles. Swepco is good but expensive overkill unless you are running the track

Posted by: bossboy302 May 14 2024, 10:37 AM

Swepco 201 baby!!

Best I've used in 50 years. Began in '73 with '67 911S. In every manual Porsche since. Also use in vintage muscle car manuals, including historic race cars.

It just plain works that good!

Posted by: ClayPerrine May 14 2024, 10:46 AM

I run 85/90 gear oil. I used to run Swepco, but I found that stuff would leak out of the vent on the top of the transmission. So you end up losing gear oil even with all the seals intact.

Posted by: StarBear May 14 2024, 11:03 AM

All great advice. Thanks ever so much!
Now a thread in the record for future searches.

Posted by: rjames May 14 2024, 11:29 AM

Add it to the (incomplete) list below....

When trying to search for topics, use google and put 914world ahead of what you're searching for. It's often more effective than using using 914world search engine.


http://www.914world.com/bbs2/index.php?showtopic=100980

http://www.914world.com/bbs2/index.php?showtopic=108957

http://www.914world.com/bbs2/index.php?showtopic=104827

http://www.914world.com/bbs2/index.php?showtopic=114057

http://www.914world.com/bbs2/lofiversion/index.php?t100980.html

http://www.914world.com/bbs2/index.php?showtopic=312722

http://www.914world.com/bbs2/lofiversion/index.php?t250161.html

http://www.914world.com/bbs2/lofiversion/index.php?t335025.html

http://www.914world.com/bbs2/lofiversion/index.php?t345635.html

http://www.914world.com/bbs2/index.php?showtopic=335025&st=25&p=2675583&#entry2675583

http://www.914world.com/bbs2/lofiversion/index.php?t272697.html

Posted by: cdn914 May 14 2024, 11:47 AM

I couldn’t agree more.

Posted by: NARP74 May 14 2024, 02:25 PM

Not sure if I am proud or disappointed that no one mentioned the transmission... George sort of did.

Posted by: JamesM May 14 2024, 03:12 PM

The cheapest 80/90 85/90 you can find. I have found sweepco to make boxes worse, same with synthetics. Not that its a bad product, just that the syncros in these boxes benefit from slightly more drag in the oil.

Posted by: Geezer914 May 14 2024, 04:29 PM

Kendall NS-MP GL-5 Hypoid gear oil 80W-90. Great stuff!

Posted by: BENBRO02 May 14 2024, 06:41 PM

I agree, my transmission shifted better with the regular cheap stuff. I think Swepco is a little too slippery or thin and doesn’t shift as well.

Posted by: Krieger May 14 2024, 10:40 PM

Sta Lube hypoid works great on the street and track

Posted by: StarBear May 15 2024, 06:52 AM

Ok, next somewhat obvious question: Not sure what was in there before, but been topping off with Swepco. OK to begin mixing by now topping with an 85/90 GL-5 oil?

Posted by: Tonyooc May 15 2024, 07:09 AM

I use Red Line.

Posted by: Superhawk996 May 15 2024, 07:38 AM

I use Astro Glide

Posted by: VegasRacer May 15 2024, 11:26 AM

Swepco leaked when I tried it in my race car. YMMV

Posted by: AZBanks May 15 2024, 11:44 AM

Dr. Evil does not recommend Swepco.

Posted by: 930cabman May 15 2024, 11:47 AM

I have been using Sta Lube (available from NAPA) GL5 and seems to work well.

Posted by: rudedude May 16 2024, 07:27 AM

I have used royal purple atf in 901/911/915 boxes since mid 70's, it was a racing trick and still never see any wear in boxes when torn down even now.
I'm not the only using it but see no need for using anything else.
Let the criticism start.

Posted by: GregAmy May 16 2024, 07:33 AM

Chris Foley recommends Lubrication Engineers Monolec Gear Lubricant 703. That's what I run in my 914s' transaxles that he rebuilt. It's a bit tough to get but you can find distributors online and locally.

Another good product is Torco MTF and RTF, which is what I run in my non-914 race cars (Hondas, Toyotas).

Posted by: technicalninja May 16 2024, 08:36 AM

That is a "trick" that the OEMs went to as well.

A box that has been 75/90w went ATF (about Year 2000?).
The T56 (6 speed LS1-2) was ATF from the start.

A hot trick for the Miata 6 speed (GL4 75/90) is to use the Ford "Unicorn juice" part# XT-M5-QS

This is the fluid for the Ricardo gear box in the mid 2000 Ford GT.

My Miata 6 speed was SO bad I had a full-on parts list for tranny rebuild.

Out of sheer desperation I tried the Ford stuff (very ATF like) and it made the overhaul unnecessary!

I wouldn't change a 914 over unless I thought I was heading for a rebuild.

I WOULD try the Ford fluid BEFORE I removed the transmission...

Posted by: Superhawk996 May 16 2024, 09:00 AM

Beware of conflating transmissions with transaxles. They have vastly different lubrication needs. Transaxle with hypoid ring and pinion is GL-5.

Don’t conflate FWD automatic transaxles running helical or spur gears with RWD transaxles running hypoid gearing. Spur and helical gears will be fine on ATF. Not so much for hypoid gearing with high loads and high sliding forces.


Note: the mid 2000s Ford GT specifies GL-5

Posted by: Shivers May 16 2024, 09:52 AM

Lucas 80w-90w

Posted by: technicalninja May 16 2024, 11:04 AM

I didn't even think about the differential!

Stupid Ninja!

Yep, no lightweight lubricant for that. GL5

I wonder HOW rudedude got away with that????

I would expect the Reaper to take the diff quickly on ATF...

Posted by: Dr Evil May 17 2024, 07:16 AM

Ah, its been a while since this was asked

cheap, non synthetic 80w90 and if you want to add some flavor, trade one L of oil for 1 of Lucas oil stabilizer. Its the opposite of too slick and works perfectly with out transaxle anatomy.

For my thoughts on synthetics and why I dont recommend them, click my link in the sig to my notes

Posted by: technicalninja May 17 2024, 09:27 AM

Just did an application search on the unicorn juice Ford stuff.

The MTX-75 and IB5 transaxles take this stuff. Front wheel drive transaxles! Not hypoid.

The dealer told me Ford GT.

I should have taken that information with a pound of salt...

They also said they NEVER sell any!

This means they ARE NOT changing the fluid on these transaxles!

A bit of internet searching came up with "The only people who buy this stuff are the Miata guys"...

If it calls for GL4 this fluid MIGHT be a lifesaver.

I'm going to go with Dr. Evil's prescription...

He is a Doctor after all!

Posted by: Root_Werks May 17 2024, 12:55 PM

Do our 914 901's have yellow metal? There's a HUGE thread on the Samba debating GL4 vs GL5 for transmissions. I'm running Valvoline 80/90 GL5 in the 914 and 75/90 GL4/GL5 in my Bug due to the "yellow metal".

Posted by: Shivers May 17 2024, 02:26 PM

I found a few write ups and everyone has an opinion. one said "GL5, no problem." But this link has a different opinion to begin with.

https://hermit.cc/tmc/bb/2018/wtd_6/index.htm#:~:text=The%20yellow%20metals%20are%20bronze,%2C%20certain%20chemicals%2C%20including%20sulphur.

Posted by: Dr Evil May 19 2024, 06:53 PM

If you care what your yellow metal looks like inside the box, sure. Its not important, thought, and the factory geeks recommended GL5 when GL4 was available. Never seen an issue with GL5, only with neglect.