Engine Oils as Gear Oils....

Status
Not open for further replies.
I ran Mobil 1 in my SAAB 900 manual. Went about 400 K without a problem. The manual shared a sump with the diff.
 
Last edited:
Depends on the gearing.. use engine oil in a subaru MT and it will self destruct.

many that spec'ed atf I'd imagine would be fairly happy with it.
 
Honda recommended ordinary motor oil for many years in its manual transmissions. Even after the introduction of Honda MTF, they still allowed for using motor oil as a "temporary replacement" and advised to replace with Honda MTF "as soon as convenient" to avoid the possibility of what the owners manual described as stiffer shifting.
 
Originally Posted By: Shannow
Given the current fascination about how engine oils perform in gear oil tests, here's an interesting (yes old) military paper on their review of utilising the engine oils in their fleet in gear oil application.

http://www.dtic.mil/dtic/tr/fulltext/u2/a202145.pdf




If I can summarise from a quick skim:-

(a) Gear oils make the best gear oils (based on some bench-tests).
(b) The best engine-oil-as-gear-oil was a straight 50 weight CD (i.e. diesel) oil, which wasn't actually part of the army inventory.

This might suggest that it isn't generally such a great idea, (especially if you aren't running a global logistics operation) and that multigrades in particular wouldn't be great as gear oils. Neither are big surprises.
 
Last edited:
Yep, and the dedicated multi purpose 0W20 did well too.

It's pertinent WRT the ongoing Rat stuff as well. It actually has some statistical analysis for starters.

The different machines, which are all there to test the "same" property rank the oils differently as well...thus what's best on a bunch of spinning balls isn't best for vane pumps with their varying pressures surface speeds and accelerations.
 
There are oils specifically designed for shared sump duty as engine and transmission - the Allison list: http://www.allisontransmission.com/parts-service/approved-fluids/off-highway-fluids We have tractors that run the equivalent of motor oil in the intermediate and final drives ...

Many gear oils overlap with motor oils in the viscosity charts. But, if your gear train requires sulfur based EP additives, it will not work as an engine oil ...
 
Originally Posted By: BrocLuno
... But, if your gear train requires sulfur based EP additives, it will not work as an engine oil ...
Yep, mainly those with hypoid gears, typical with non-transverse engines. Not as critical with all parallel-shaft helical gears (transverse engine manuals).
 
Originally Posted By: Padawan
Honda recommended ordinary motor oil for many years in its manual transmissions. Even after the introduction of Honda MTF, they still allowed for using motor oil as a "temporary replacement" and advised to replace with Honda MTF "as soon as convenient" to avoid the possibility of what the owners manual described as stiffer shifting.


Yup. My '87 CRX (RIP, I loved that car) spec'ed 10W30 in the 5 speed gearbox.
 
Originally Posted By: Padawan
Honda recommended ordinary motor oil for many years in its manual transmissions. Even after the introduction of Honda MTF, they still allowed for using motor oil as a "temporary replacement" and advised to replace with Honda MTF "as soon as convenient" to avoid the possibility of what the owners manual described as stiffer shifting.


Yes, Honda, the pinnacle of reliable automobiles in the 70s, 80s, 90s .. recommended nothing but motor oil in their transmissions, 10/40 if I remember correctly, some manufacturers still do. I had two hondas, manual trans, years back, 77/78 Accord and later a CRX.
 
Last edited:
Originally Posted By: Surestick
Originally Posted By: Padawan
Honda recommended ordinary motor oil for many years in its manual transmissions. Even after the introduction of Honda MTF, they still allowed for using motor oil as a "temporary replacement" and advised to replace with Honda MTF "as soon as convenient" to avoid the possibility of what the owners manual described as stiffer shifting.


Yup. My '87 CRX (RIP, I loved that car) spec'ed 10W30 in the 5 speed gearbox.


Yes! Me too! I think that was it, an 87.
 
Back in the 1960s several British car makers used regular engine oil in their transmissions, BMC fwd cars effectively used the transmission as the oil pan. Even in cars equipped with the AP automatic transmission. They had a very short lifespan it should come as no surprise.
Also a few cars used atf in their stick transmissions.

Claud.
 
Originally Posted By: Claud
... Also a few cars used atf in their stick transmissions. ...
For example, my '81 Mazda specified Type F ATF. Relevant of not, some of the transmission bearings needed replacement by about 360K---which was the most expensive repair ever on the car. According to the shop, the gears and synchronizers were still in very good condition.
 
we run 40wt non detergent in the 93 toyota 5 speed trans. shifts great. well over 200K on it.
 
My '91 CRX (EE8 with the 150 bhp B16A1 engine) also specified 10W-40 engine oil. Me being me I once tried a high-spec, synthetic MTF in it and it was awful, so it got semi-synthetic 10W-40 which was fine. Many CRX enthusiasts swear by Honda MTF or the similar Land Rover MTF94.
 
Originally Posted By: Claud
Also a few cars used atf in their stick transmissions.


C5 Corvettes use DEXRON III ATF in the 6-speed that can handle 400+ HP.
 
Originally Posted By: Claud
Back in the 1960s several British car makers used regular engine oil in their transmissions,.


BMC, like other British manufacturers used the same drive train in sedans, sports cars and commercial vehicles. BMC recommended engine oil in the gearbox, but that same gearbox used in a J4 van took EP90 gearoil...which was all the same back then.

Worm drive rear axles in trucks, and the Peugeot 404 used a 30 weight castor oil...there was no mineral oil that could handle it back then.
 
Type F ATF was specified for my Mazda's manual transmission. When the bearings had to be replaced (at about 360K) the shop filled it with a higher viscosity oil they said was a synthetic gear oil, but couldn't (or wouldn't) tell me specifically what it was. Thereafter, the transmission was much quieter than ever, but tended to burp oil out its breather vent, even if the level was alarmingly low.

Most, if not all, Honda manuals in those days required engine oil.
 
Status
Not open for further replies.
Back
Top