Which Transmission Fluid, Use? Suggestions? Options

[rudedude]

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.

[GregAmy]

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).

[technicalninja]

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.

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...

[Superhawk996]

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.

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...

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

[Shivers]

Lucas 80w-90w

[technicalninja]

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.

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...

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

(IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/agree.gif)
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...

[Dr Evil]

Ah, its been a while since this was asked (IMG:style_emoticons/default/smile.gif)

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 (IMG:style_emoticons/default/smile.gif)

[technicalninja]

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! (IMG:style_emoticons/default/beerchug.gif)

[Root_Werks]

Ah, its been a while since this was asked (IMG:style_emoticons/default/smile.gif)

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 (IMG:style_emoticons/default/smile.gif)

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".

[Shivers]

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.h...uding%20sulphur.

[Dr Evil]

Ah, its been a while since this was asked (IMG:style_emoticons/default/smile.gif)

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 (IMG:style_emoticons/default/smile.gif)

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".

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.