5 speed gear oil

[snafu1]

Hello everyone, I want to change the transmission gear oil in my 2003 P5 manual transmission. What is the best oil to use? I know it is speced at 75-90, but what has everyone been using for smooth and trouble free shifting?

Thanks

 

[pcb]

I think you should go with syncro-mesh oil...

I don't know how cold it gets where you live but when it was below freezing here, I would grind every gear for the first 20 minutes after I started my car.

We don't have hypoid gears in our transmission so we don't need the special additives that come in regular gear oil ( like sulfur that makes it stink ).

Some guys in my area tried Redline synthetic gear oil but when it was - 20 degrees out they would still grind their gears.



On a side note... I decided to go with ATF type F
(which was recommended for my Mazda GLC for cold weather. F for "friction modified" for old school auto transmissions)
...and a liter of Lucas oil.

Some guys on this forum told me to "Get That s*** Outta Their !! " but I friggen love it... It's been two or three years now and I've had no leaks and I get NO grinding now ever... Even when it was -40 out a couple of years ago during the polar vortexes.

Bare in mind.. If you drive around slammin gears like Mario Andretti (or Danika Patrick ) then you might want the cushion provided with regular gear oil...

 

[Stickman]

Back in the day when I knew something, I believe I read sulphur product gear oil deteriorated the brass components in the synchros. I believe valvoline has a sulphur free product. It's been a while though.

 

[pcb]

Back in the day when I knew something,...

Here today while I still think I remember something...

Hypoid gears don't just push teeth on teeth,... they "scrub" as they rotate so they need extra protection... That's what the sulfur additive helps with.

Perhaps they have a synthetic version additive that avoids the need for sulfur... I dunno...
(I'm mostly concerned with keeping my ass from falling through the floorboards at this point)

 

[MrGiggles]

The book says any 75W-90, GL4 or GL5. GL5 is formulated for EP and hypoid gears and can contain sulphur. There is no hard evidence that I've found to prove or disprove that it eats synchros.

Most prefer to play it safe and use Redline MT90. It's 15 dollars a quart, but there's no worry of sulphur, and it shifts nicely.

I'm using mostly Supertech synthetic blend for over a year and 30,000 miles with no discernible damage to my synchros. I say mostly because I have a weeping axle seal and have topped it off with a quart or so of Dino 80W-90 GL5.

Pennzoil Synchromesh is not a bad choice either.

 

[snafu1]

Thank you for the help. I will either try Redline MT90 or the Syncromesh. Does anyone know the correct part number for the Syncromesh gear oil I should use?
Thanks again for the help.

 

[pcb]

This stuff ↓↓↓ I don't know if it has a part number...







GM has product too ↓↓↓

 

[snafu1]

Great, thanks so much for the info and help!

 

[snafu1]

Oh an pcb, I live in California.....San Francisco South Bay, it doesn't get cold here. Well at least not like Canada cold anyways! Thanks again.

 

[pcb]

Oh an pcb, I live in California.....San Francisco South Bay, it doesn't get cold here...

Then it would probably be best to go with Redline or regular gear oil if you don't want to spent that kind of money.
You'll need three quarts.

 

[snafu1]

Well, I replaced the shift like bushings, just the factory ones for now. Tightened the shifter bolt to 15 ft lbs and filled the transmission with Redline T90. What an AMAZING DIFFERENCE! SO MUCH SMOOTHER! Thank you all for the info and help.

 

[smetzger]

I use Motorcraft MTX-75.
- The miata guys swear by this stuff
- miata takes same spec gear oil as P5
- mine was developing a 3rd gear grind and this cleared it up

Its expensive from the Ford dealer. So your gonna wanna buy it here..
http://k-mansparts.com/motorcraft-mtx-75-ib5-transmission-fluid-xtm5qs-quart-detail.htm

 

[Preferio]

The book says any 75W-90, GL4 or GL5. GL5 is formulated for EP and hypoid gears and can contain sulphur. There is no hard evidence that I've found to prove or disprove that it eats synchros.

EP (Extreme Pressure) additives that contain sulfur are known to cause chemical corrosion. This is why the copper strip tarnish test exists for these. The higher the levels and the type of sulfur used will dictate how fast the wear is to yellow metals.

 

[Preferio]

And, to throw in my two cents, I use OEM GM Syncromesh, not the Pennzoil equivalent.

 

[Luken10]

I use Motorcraft MTX-75.
- The miata guys swear by this stuff
- miata takes same spec gear oil as P5
- mine was developing a 3rd gear grind and this cleared it up

Its expensive from the Ford dealer. So your gonna wanna buy it here..
http://k-mansparts.com/motorcraft-mtx-75-ib5-transmission-fluid-xtm5qs-quart-detail.htm

This is what I use. Did a bunch of research a while back, and this seemed to be the best for our transmissions. It seems like every after market oil had the potential to ruin some part of the transmission. Of course I'm sure this isn't true, I just wanted to play it safe. I can't say I've had a problem while using it.

 

[pcb]

This is what I use. Did a bunch of research a while back,... I can't say I've had a problem while using it.

Me Either !!! Sept I did no research !!!

 

[Luken10]

At the end of the day, whatever works!

 

[PaulyD]

I put in Royal Purple.

Had the third gear grind issue which it helped.

 

[SlowturboP5]

I used eneos gear oil. I think shifting got notchier now but i dont know what was in it before. Never grinded though before and after.