Gearbox oil

[HealeyBN7]

Good discussion.  I choose Redline Lightweight Shock Proof.

https://www.redlineoil.com/product.aspx?pid=43&pcid=7

From the Redline site they claim:
    "Film thickness greater than an SAE 75W140, yet low fluid friction like 80W gear oil or 30W motor oil
    Excellent low-temp flow, improved cold shifting
    For racing differentials under moderate loads
    Popular in racing transmissions like Hewland and other Road Racing dog-ring boxes, Bert and Brinn for Stock Cars, G-Force, and Liberty clutchless for Drag Racing"

I'll admit that I like it for the simple fact that it stays sky blue.  When I see a drip under the car, I know exactly where it came from.

Dean

[Gearbox]

I found out some more information from my friends in the Porsche community that may be helpful.  Swepco 210 is the oil of choice for track day cars and spirited driving and the Swepco 201 is for moderate and occasional driving.  Both are reported to improve shifts and are long lasting.  They also use Swepco 203 which is a moly blend which prevents overheating and oil consumption on high HP cars like the 911 Turbo, but I think that would be overkill in our cars.  The 201 sports an ingredient called Lubium which apparently coats the internal parts and provides a protective film and most likely the reason they use it in non daily drivers.  The 201 is a true EP oil (excessive pressure) and is a Hypoid oil.  And finally, all these oils are blue lol. 

[SilverBeast]

I know this is an old thread, but it's gearbox oil I'm asking about!

What are the current oil recommendations ( in the UK) for road use in the 365  transaxle?

Thanks,
Richard.

[Pfreen]

I recently switched from Millers 80w-90 to Swepco 210.  They both don't attack yellow metals, but the Swepco is higher viscosity.  I was getting gear knock at idle in neutral with the Millers oil. However, my car has a high lift cam and an aluminum flywheel, which makes the idle somewhat lumpy.

[jbcollier]

The most important thing is that you regularly check the oil level until you get a handle on consumption.  Yes, they all leak at least a little bit and 5th gear is the first gear to be left high and dry.  My transaxle hardly leaks anything.  I check it at the start of the season, mid way through, and before any trip.

[BDA]

I posted earlier in this thread that I use Red Line 75W90NS but I discussed it with the tech guy at Red Line and he said a GL-5 is not necessary because the offset of the pinion to the crown gear isn't enough so he suggested their MT85 which is their 75W85 GL-4 gear oil. I like Red Line products but I think any good gear oil (GL-4 or GL-5) from 75 to 90 wt. would do. As JB says, the important thing is to make sure you always have oil in it.

[MRN I J]

as my old boss used to say when someone complained about oil leaks on British Classics 'The time to worry is when it stops leaking oil'

[TurboFource]

My son's 2 wheel drive, 5 speed Jeep Cherokee was so bad you could barely shift into second.....with Redline MTL it will now shift.....the stuff is awesome !     (I am sure the Jeep could use new synchro at some point)

[BobW]

I use Red Line too, currently the GL-4 MTL mentioned by BDA but it's SAE 75/80. I remember noticeably improved gearchanges the first time I used it.

[jbcollier]

I run Redline MT-90.  The 1st - 2nd shift is noticeably better when cold.

[Clifton]

I did a lot of searching when my Nissan truck trans with 250k miles started grinding pretty bad on 2nd-3rd shifts that had fresh Valvoline GL4 in it. I ended up with Motorcraft XT-M5-QS, it's made by Castrol for Ford. After about 500 miles it felt like new, has 334k on it now.  Many Miata people use it for what it does with syncros. Ford specs it for Transaxles and I run it on a Toyota transaxle too.  It's full synthetic so it's not cheap, none are though.

Read the reviews on Amazon.
https://www.amazon.com/Genuine-Ford-XT-M5-QS-Synthetic-Transmission/dp/B000NUES82

https://www.motorcraft.com/content/dam/ford-motorcraft/en_us/motorcraft_global/products/lubricants/quick_reference_charts/manual%20transmission%20fluid%20chart.pdf

[literarymadness]

I use Driven GO 80W-90 Conventional GL-4 Gear Oil. It is specifically formulated for vintage street and race cars with yellow metal. Made from Pennsylvania oil. It was spec'd by Joe Gibbs from Joe Gibbs Racing (use to be his company). I have a 352 gearbox with an aluminum flywheel and a bored and stroked, high compression, Twin Cam motor with Hot Street Cams.

https://drivenracingoil.com/i-30497794-go-80w-90-conventional-gl-4-gear-oil.html

[Kendo]

If you have one type of oil in the transmission and want to switch to a different one, say a synthetic, can you just drain the old oil and fill with new? Or should there be a flush cycle of some sort?

[Clifton]

If you have one type of oil in the transmission and want to switch to a different one, say a synthetic, can you just drain the old oil and fill with new? Or should there be a flush cycle of some sort?

I switched from regular to synthetic with a drain and refill. It took 500 ish miles before the syncros started to work better. I don't think a flush works on manuals. You can't get the old oil out of the syncros. The new oil has to work its way in.

[jbcollier]

Don't "flush" a transaxle.  Debris settles in nooks and crannies and is no problem as it is stable.  Introducing a flushing agent and the deposits are "cleaned" out, mix with the oil and circulate through your bearings and gears.