Motul gear 300

[Popsy]

Hi there,

Long story short, my car got a "new" (only 217K Km) gearbox, so I have now two cars with Fiat C510 gearboxes.

In one I put some Motul gear 300 75W90 like 2000Km ago, and I am not impressed. When cold everything is ok, no problem shifting, everything is smooth, etc, but when hot, the gearbox is very notchy, difficult to put into any gear, if you are silly enough to push the engine above 4000rpm you can almost say goodbye to do 3-4 or 4-5, and when you are stopped at a red-light, you have to think twice before engaging the first speed.

I admit I am much more delicate with the engine and gearbox when cold, but there's definitely something happening with heat, the longer I travel, the more horrible the gearbox becomes. I am surprised because Motul gear 300 is usually highly regarded, and someone on the forum said he had better luck with gear 300 than OEM liquid (Selenia ZC 75 synth).

The other C510 gearbox is currently filled with Castrol syntrans multivehicles 75W90 and is perfectly smooth, cold or hot.

Should I dump the gear 300 and replace with something else? I'd be a bit disgusted to do that, considering the price of this oil

 

[BigCahuna]

It may not be what you want to do, but sounds like you should do it to get the drive-ability where you want it to be.,,,

 

[aquariuscsm]

If it's not shifting right,dump it and replace it immediately.

 

[Rand]

What does the gearbox call for. If it does not require API GL-5 gear oil. I wouldnt use one. They generally cause bad shifting from their excessive unneeded additives (vs GL-4).

I would only use api gl-5 gear oil in an application that calls for it such as the subaru's with the combo Diff/MT sump.

If it requires api gl-4, Redline MT90 would be much superior in shift feel.

 

[dparm]

Originally Posted By: Rand
What does the gearbox call for. If it does not require API GL-5 gear oil. I wouldnt use one. They generally cause bad shifting from their excessive unneeded additives (vs GL-4).

I would only use api gl-5 gear oil in an application that calls for it such as the subaru's with the combo Diff/MT sump.

If it requires api gl-4, Redline MT90 would be much superior in shift feel.



Rand,

Gear 300 is dual-rated GL4/GL5. I used it in my Audi S4's manual transmission for years without issue (spec'd for 75w90 GL4).



To the original poster,

If you aren't satisfied with the feel, change it. There are plenty of other fluids out there. We're not talking about thousands of dollars to change it, so why not just spend $100-200 and get the feel you really want?

 

[Rand]

Originally Posted By: dparm

Gear 300 is dual-rated GL4/GL5. I used it in my Audi S4's manual transmission for years without issue (spec'd for 75w90 GL4).


I had motul gear 300v in my subaru. It is slightly better than redline 75w90NS.

I had previously tried the motul gear 300v in a 2007 ford focus and it was terrible. VS redline mt90.

Would feel notchy when cold.. and "loose" when hot.

 

[Cardenio327]

Are you sure it's not a mechanical issue? Your flywheel or pressure plate could be warped. As temperature increases, clutch release clearance would decrease, causing the clutch to drag.

 

[Popsy]

I don't think there is a mechanical issue, problem started with gear 300 oil...

I don't have the original manual, but according to a late Barchetta manual (same gearbox slightly different engine) the gearbox is calling for GL-5 75W80 oil. According to the manual from my other car with identical gearbox and three different technical sources for the other car, it is calling for GL-4 75W90 oil...current data for this gearbox say 75W80 GL-5 (Fiat) or 75W85 GL-4+ (Alfa).

I'm going to dump the oil and replace it by some Castrol syntrans transaxle (what the Castrol website is recommending, and what seems a good compromise, since Castrol and Motul are the only two brands of gear oil I can buy easily), unless you have another opinion (I know about red line but qi have limited access to Red line engine oil and not to gear oils)?

 

[dparm]

Moutl makes a 75w80 GL4/GL5.

 

[GiveMeAVowel]

Originally Posted By: Popsy
I don't think there is a mechanical issue, problem started with gear 300 oil...

I don't have the original manual, but according to a late Barchetta manual (same gearbox slightly different engine) the gearbox is calling for GL-5 75W80 oil. According to the manual from my other car with identical gearbox and three different technical sources for the other car, it is calling for GL-4 75W90 oil...current data for this gearbox say 75W80 GL-5 (Fiat) or 75W85 GL-4+ (Alfa).


For your synchronized manual transmission use a GL-4 spec fluid only! Probably an error in those other manuals.

Castrol Syntrans GL-4 is a very good product. I'd go with the
75w-85 first.

I'm going to dump the oil and replace it by some Castrol syntrans transaxle (what the Castrol website is recommending, and what seems a good compromise, since Castrol and Motul are the only two brands of gear oil I can buy easily), unless you have another opinion (I know about red line but qi have limited access to Red line engine oil and not to gear oils)?

 

[zeng]

Originally Posted By: Popsy
I don't have the original manual, but according to a late Barchetta manual (same gearbox slightly different engine) the gearbox is calling for GL-5 75W80 oil. According to the manual from my other car with identical gearbox and three different technical sources for the other car, it is calling for GL-4 75W90 oil...current data for this gearbox say 75W80 GL-5 (Fiat) or 75W85 GL-4+ (Alfa).


Why does it not calls for GL4 , over and above GL5 and GL4+?

It's synchronizer is unconventional in terms of materials/coatings/design/clearances ?

Plus the issue of synchronizing when the Motul gear oil is warm/hot .....

Just curious..

 

[Popsy]

I don't know, I am clueless with all the different specs I can find.

The most common specs is that Tutela ZC75 synthetic is recommended, but this oil itself seems to have had various specs in the last twenty years...just like the Selenia Turbo diesel oil was a 15W40 in 1996, but is now categorized as 10W40 and had different formulations over the years (wich is not uncommon in the oil world)...

The gearbox is a C510.5.17, as far as oil specs go, I've found :

1996 manual : ?
1998 manual : 75W90 GL-4
1998 service manuals (x2) : 75W90 GL-4
2001 manual (Alfa) : 75W85 GL-4+ (Tutela car technyx)
2003 manual : 75W80 GL-5
2006 manual : 75W85 GL-4+ (Tutela car technyx)
Currents specs : 75W80 GL-5
Haynes service manual : Tutela ZC75 synthetic (lol)

In some manuals it says Tutela ZC75 synthetic but that Tutela car technyxis the FF

 

[supercity]

I've used a multitude of oils in the C510, mostly older models. Factory spec was GL-4 80w in most (ZC80s). By far the best shifting oil was ZC75 synth, GL-5 75w80 version. I would use that or a synthetic GL-4 75w85

 

[chrisri]

Popsy, you are right, FIAT changed specification on those gearboxes few times (C514 as well).

There were some modifications on c510 depending on applications, and linkages are different. Alfa Romeo has more refined ones which is no surprise since they are more expensive cars.

Nonetheless I'm surprised 300V didn't do it's "magic" in your FIAT. It worked well in my AR. Currently I have none of c510, but I have c514 filled with Syntrans Transaxle. Previous fill was ZC75 Synth. I had exactly the same problem with Tutela as your with Motul; very smooth on coldest mornings (4-5*C), but as soon as at temp. very notchi with difficult first gear engaging.

Castrol cured most of the problem, but not all. Way better though, I'm satisfied for a 250k, 17 years old car.

I believe ZC 75 has massive amounts of additives, and it is on the thinner side. Old synchros simply don't work as well as new with these oil.
Most current spec is Car Technyx 75w85, a GL4+ lubricant. DO NOT use plain GL4 if you don't want to see your diff OUTSIDE of your gearbox casing.

Edit; I'm using ZC75 in Getrag in my Stilo. It works brilliant even though it was never specified for GL5 MTF.

 

[Popsy]

Oh, I'm using GL4 Castrol Syntrans multivehicle in one of my C510

You say I should change it right away? I am very satisfied with it in a 18yo car, very very smooth, the best gearbox I've tried (feeling wise).

I'm almost sold on Castrol Syntrans transaxle at the moment. I still haven't ordered anything...Castrol oil range seem the best quality/price ration here, I don't want to buy Motul since except Gear 300 and Motylgear others are a nightmare to order.

 

[chrisri]

Being GL4 aids shifting smoothness. Maybe you are OK if you're not an aggressive driver, and gearbox isn't working on its upper torque limits (depending upon engine in your car).

Regarding Syntrans Transaxle, I guess I expected more. I had great experience with it before, and this time that ease and smoothness is missing. It works adequately.
I wouldn't say it's lubricant fault, just worn out gearbox.
Don't bother with Motul if 300V does not work. 300V and Transaxle are two of the very best fluids on Euro market.

 

[Popsy]

Engine is 1910cm3 TD 100hp. I'm still looking for all the hp but still more torque than gasoline engines. I guess I should change the oil in the near future...

So one more point for Castrol transaxle. What do you think about Castrol Syntrax Universal + ? The price is identical to Transaxle and it has many approvals.
I can buy Castrol gear oil locally for decent price, will probably buy some on Monday.

 

[chrisri]

I'd rather go with Transaxle, it's well regarded product, amongst best for our application. Universal is more for commercial vehicles, I can't see it being better than Transaxle for transaxle gearboxes on cars. I believe Transaxle is FF on a Lotus, MINI, etc.

 

[Popsy]

Ok then, let's try transaxle!
I hope it will help smoothing out the Barchetta gearbox and keep the Marea alive

 

[chrisri]

Report back! And save that 300V in a clean bottles. Don't waste good oil.