Turbo Transmission Oil

Quarterflash · Apr 14, 2023

Hello everyone
I have an 89 Turbo and am thinking about replacing the oil in my Transaxle (not sure how long it has been in there).
1 Is there an actual drain plug?
2 What oil is recommended considering it has the LSD and an oil cooler?

Thanks
Q

Eldavo · Apr 14, 2023

1 - There is both a drain and a fill plug, make sure that you can undo the fill plug before you remove the drain plug.
2 - Swepco is very popular, I used Royal Purple Gear Oil in mine - 75w-90

blade7 · Apr 14, 2023

It's been around 15k miles since I changed the transmission oil in my turbo, and I'm thinking about changing it again. The gearbox in my daughters Fiesta was slightly noisy a while back, so I changed the oil in that. And now I've got around 3/4 of a litre of Titan race syn 5, and 3/4 of a litre of Castrol syntrans left over, both 75w 90. As I seem to recall the oil wasn't cheap, so I'm wondering if I can mix the leftover Titan and Castrol for part of the refill.

scam75 · Apr 14, 2023

As he says ^^^

A good synthetic 75w-90 or if you wish to quieten things down a tad and have a super long service life then go for Swepco 201, which is 80-90, and a lovely blue colour! I've been using Swepco since my box rebuild. It can be a tad notchy on start up when frozen cold, however if you let it idle for a minute in neutral before you set off, it should be fine. This is typically 5 degrees and cooler weather I find this helps in. Not necessary when warmer.

If you go with Swepco, its much easier to pump it in rather than pour it in. And the warmer it is, the easier it will be to get it in the box.

You fill it right up to rim of the fill plug. About 2 litres on a standard turbo box.

Both plugs are a 17m female hex I think, but don't quote me on that.

Stuart

scam75 · Apr 14, 2023

blade7 said:
It's been around 15k miles since I changed the transmission oil in my turbo, and I'm thinking about changing it again. The gearbox in my daughters Fiesta was slightly noisy a while back, so I changed the oil in that. And now I've got around 3/4 of a litre of Titan race syn 5, and 3/4 of a litre of Castrol syntrans left over, both 75w 90. As I seem to recall the oil wasn't cheap, so I'm wondering if I can mix the leftover Titan and Castrol for part of the refill.

I'm no expert but I don't think mixing brands would be a problem as long as the same grade/type.

I used to top mine up frequently when I got the car with Halfords 75/90 semi synth. I had no idea what was already in the box and it didn't cause any problems. Incurable cooler loop weep despite new o-rings. Of course when the cooler loop breaks altogether when driving is a bigger problem...........[8|]

TTM · Apr 14, 2023

I use Motul gear 300 LS 75W140. I have found that our transaxles tolerated heavy grade oil well and I am sure they are the best to preserve bearings. Shifting remains smooth in my experience, even in cold weather.

blade7 · Apr 14, 2023

scam75 said:
As he says ^^^

A good synthetic 75w-90 or if you wish to quieten things down a tad and have a super long service life then go for Swepco 201, which is 80-90, and a lovely blue colour! I've been using Swepco since my box rebuild. It can be a tad notchy on start up when frozen cold, however if you let it idle for a minute in neutral before you set off, it should be fine. This is typically 5 degrees and cooler weather I find this helps in. Not necessary when warmer.

Stuart

I've got a Shark Motorsport linkage on my turbo gearbox, so I'm used to a slow shift from 1st to 2nd gear until the gearbox oil has warmed up a bit. I do miss the quickshifts on my mk2 RS Escorts though.

scam75 · Apr 14, 2023

I think notchy 1st to 2nd changes on cold boxes are very common, my old box done it, my interim box done it and my rebuilt box does it.

A couple of things I've noticed. Cold 3rd to 2nd isn't notchy at all, and if you let the lever return to neutral in between a cold 1st to 2nd change, it's usually much less notchy. Thinking about it, you pass through neutral on a 3rd to 2nd change, so ties up with my theory.

Sorry to sidetrack the thread a bit..........

Stuart

dlknight · Apr 18, 2023

I used Swepco for a while and found it really notchy in the cold (it is very thick oil - you can see that when you pour it). Then the last time I filled it I used some Millers fully synthetic gear oil specifically for LSD equipped gearbox (which I got from Stuart).

Could the notchy thing when cold be something to do with the reinforced 1st and 2nd gear in the Turbo box?....

Just noticed you have a Chevy swap in your 944, is this the red one with the LS1? If so I chatted to you about it at Wheels on Wednesday at Spetchley Gardens nr Worcester some time ago

scam75 · Apr 18, 2023

I might still have some more of that oil in the shed...........

Swepco is marmite in the Porsche community. I've essentially got a Frankenbox made up to AOR spec from 1 x toasted AOR box (only the LSD survived), 1 x worn non LSD turbo box (the crown and pinion was mint though and the gears ok, except reverse, you could hear that from 4 miles away..........) and 1 x box of assorted turbo cogs that Simon sent me up. My cooler is also non-standard, but better!

I have a bit of idle chatter when warm (common), and my 3rd and 4th are a bit whiny over 4k revs, the Swepco keeps all that to a minimum. So I put up with the cold notchy-ness as a trade off. It's also got a mega service life which is nice.

Essentially a fresh or good nick box would be fine on a good 75/90 synth, like the Millers stuff, and a worn or noisy or quirky box (like mine) is most likely better on Swepco to keep it running for years to come as quietly as possible! These 016 boxes are as tough as old boots, if a bit noisy, it was the 3rd emptying of gearbox oil that finally done for mine..........[&:]

Stuart