Best oil for Tremec T5 gearbox (out of TVR)

SuperV8 · Post by **SuperV8** » Wed Jul 28, 2010 11:59 am

Hi,
Anyone recomend a good oil for the Tremec T5 out of a TVR Tuscan?

Thanks,
Tom.

richardpope50 · Post by **richardpope50** » Thu Jul 29, 2010 4:56 pm

Tom,

TVR say "Gearbox oil Mobil SHC ATF or Dexron III ATF"

Post by **Coops** » Thu Jul 29, 2010 6:35 pm

Sorry to hijack the post,
do they say what to use in a R380 box??
mine has what looks like meth spirt in it, same colour purple

Post by **katanaman** » Fri Jul 30, 2010 4:02 pm

Castrol recommends TQD same for you T but SMX-S as an option for the R380. It doesn't list that for the TVR though which is odd as they used to.

richardpope50 · Post by **richardpope50** » Fri Jul 30, 2010 4:22 pm

To paraphrase from my TVR manual ...

TVR initially recommended for R380 EP80 oil but as it is quite thick, gave selection problems on 2nd and 3rd when cold - OK when warm. Then it was Castrol TQF but gave TVR concern over ability to lubricate because it was an automatic oil. Then TVR changed to SMX as it is a synthetic automatic fluid.

OK?

davehoos · Post by **davehoos** » Sat Jul 31, 2010 11:29 am

tremec --CASTROL TQ DIII 3.5l
later spec is CASTROL TQF

I use an engine oil 30-40 SAE
CASTROL VMX 80 SAE -75W/80, API GL4
CASTROL SYNTRANS 75W/85 API
as auto oil tends to leak out.

DaveEFI · Post by **DaveEFI** » Sat Jul 31, 2010 1:55 pm

richardpope50 wrote:To paraphrase from my TVR manual ...

TVR initially recommended for R380 EP80 oil but as it is quite thick, gave selection problems on 2nd and 3rd when cold - OK when warm. Then it was Castrol TQF but gave TVR concern over ability to lubricate because it was an automatic oil. Then TVR changed to SMX as it is a synthetic automatic fluid.

OK?

Autos have planetary gear trains not so much different from the gears in a manual - nor really are the bearings. What ATF does have to stand is extremely high temperatures compared to a manual. I'd guess they require a 'better' oil than a manual - certainly at one time it was much more expensive.

davehoos · Post by **davehoos** » Sun Aug 01, 2010 9:57 am

also cant find SAE to API conversion chart.
10W-40 is thicker than 75/80.

have a 20L drum to try of syn nulon multi auto oil that is in common use without drama and in bulk is half price.

davehoos · Post by **davehoos** » Sun Aug 01, 2010 10:24 am

good web site
http://www.penriteoil.com.au/oil_selector.php

I also found a good shell site that has simple to read specs for fleet oil products.

5000SE · Post by **5000SE** » Sun Aug 01, 2010 2:58 pm

In the case of both boxes, just use synthetic engine oil - that's what anybody who's worked on the technical side of the oil industry does.

The ATF recommendations in LT77 boxes only came originally when Rover had trouble with heavy gearchanges when the oil was cold, so switched to an ATF recommendation. It was good enough to do the job (just about), and thinner than normal weight gear oils so gave better cold shifts. Other manufacturers clutch at this same straw in temperate climates when boxes are temperamental at cold start - but while it works, ATF does not offer the same level of long-term protection as normal oil.

(ATF reduced the life expectancy of LT77s, but not enough to cause warranty problems (ever wonder why old LT77 boxes are always shagged?)).

The oil industry has been laughing heartily for many years over automotive gear oil sales - the gear types in an automotive manual box do not require the high pressure additives that a diff needs, so just a good quality straight base stock of the right viscosity does the job very nicely.

At working temperature, 40-50 weight engine old is close enough to 80/90 gear oil (gear oil viscosities are calculated differently).

It goes against the grain for some people to accept this, but putting something like Mobil 1 engine oil in these gearboxes is not just an alternative, it's about the best you can do for them.
I persuaded a TVR garage I know to switch to engine oil in their gearboxes and for the last 15 years of doing this they've never looked back.

davehoos · Post by **davehoos** » Mon Aug 02, 2010 3:24 am

I worked at landrover on assembly line late 80's
we didnt use ATF and i dont remember draining ATF from new boxes.

synthetic oil is good but not at 5-6 times the cost.

most of the car dealers ive worked for add a ATF blend to help clean the the insides and improve shift quality.holden and nissan often filled the box with ATF to run in a trans and then refill with better oil to stop the gear rattles/whine.

my rangerover came with receipts for $1000's in new gears.its dreadfully noisey in low gears and temp has no effect on variable shift quality.
its just a poor euro designed box.

SuperV8 · Post by **SuperV8** » Mon Aug 02, 2010 12:16 pm

Thanks guys,
Think I have read somewhere about Mobile 1 being approved for the T5 by tremac?

I think for the time being i'll go ATF. I'll see how it runs with that, I need to run my engine in so come the first oil change i'll review and maybe so syn engine oil. It's only 1.5L so may even have enough left over from the oil change once run in and I change to a good oil.
Tom.

unstable load · Post by **unstable load** » Mon Aug 02, 2010 3:11 pm

Get yourself a magnetic drain plug so you can see if there is any breakdown of the gears and bits.

ATF is pretty good stuff. A few helicopters use it in their main and tail gearboxes and they carry a mean load, stress wise.

5000SE · Post by **5000SE** » Mon Aug 02, 2010 4:22 pm

davehoos wrote:synthetic oil is good but not at 5-6 times the cost.

In some gearbox applications, trials on synthetics have seen lifespans extended by 500%.

At the least, you can expect to double the life of a gearbox by running it on synthetic.

I'd say synthetic oil works out pretty cheap.

(The same goes with engine oils - you greatly extend engine life, and at the same time actually spend very little more on oil because you can double the drain period).