Using 20w50 motor oil in a tranny where 75w90 GL-5 is specified?

[Dave]

pgtr, you're missing one critical thing, at least in this particular case where we're discussing using a GL-4 in the transmission of a Subaru.

Subarus share the front diff with the transmission. Would you run a GL-4 in your rear-end?

 

[pgtr]

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Originally posted by Dave:
pgtr, you're missing one critical thing, at least in this particular case where we're discussing using a GL-4 in the transmission of a Subaru.

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No I'm not missing that - my response was specific to Sprintman and his note on factory recomendations for transmissions. Note the relevant quote included in my response.

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Subarus share the front diff with the transmission.

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That's the definition of a transaxle and and a different question altogether. Again, my response was specific to the quote I included. And yes, Subarus have been manufacturered that have either transaxles or traditional discrete transmissions and differentials.

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Would you run a GL-4 in your rear-end?

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I've already answered this elsewhere but again no, I would not run GL-4 in a differential nor would I recommend anybody do this. As folks should know, a GL4 can potentially ruin a differential gear set in short order. I thought I was speaking clearly to transmissions and not transaxles or differentialls but if not; my response was specific to the quote I provided and to transmissions, not transaxles, not differentials. Hope that helps clarify and one can never be clear enough w/ respect to GL4s

thanks,

PS: Just like I tend to take a critical view of manufacurer GL5 recomendations for a transmission, when it comes to a manufacturer recomending a GL5 for a transaxle, I would also tend to differ from the manufacturer and consider exclusively focusing on the GL4/5 'combo' lubricants that a 'few' companies offer. I believe RoyalPurple was mentioned above - that being an example.

So to sum up, traditional/generic recomemndations (and these do have to be considered on a case by case basis and doesn't speak to units designed for ATFs or proprietary fluids etc...)

Manual Transmissions: GL4
Transaxles: GL4/5 'combos'
Differentials: GL5
Transfer Cases: ? (GL4, GL5, GL4/5) ?
Automatics: (subject unto itself - don't know a thing about it)

Again, these are only my general 'generic' start points I've followed and have to considered on a case by case basis and don't take into account many modern boxes designed for different fluids altogether outside the 'GL' realm.

 

[sprintman]

When I said transmission I meant transaxle. As all Subes sold here in Oz are AWD the word transmission is used, not transaxle. Just a different way of using English.

 

[pgtr]

Thanks for the clarification. You're right, I had thought you meant transmission, not transaxle. Again, thanks,

 

[Christopher R. Wise]

quote:

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Originally posted by Dave:

quote:

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Originally posted by Bror Jace:
Back to the original subject ...


[qb]In the WRX's transmission (calls for a 75W90?) I'd probably opt for Red Line MT-90.

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Subaru calls for a 75w90 GL-5 oil. I would guess this is because the transmission shares fluid with the front differential (Subaru AWD). Not surprisingly, many people are using MT-90 because it shifts great, but I am hesitant to use it myself. Maybe if you guys can convince me that a GL-4 is OK for the front diff I'll give it a go. Even a well respected WRX tuner highly recommends MT-90 for the transmission, but who knows how long the diff will last with it in there...

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Redline recommends the MT-90 for transaxles, the diff in a transaxle is not quite the same as a rear diff.Some transaxles recommend ATF, how long do you think those diff will last. It seems to work. Most transaxles diffs I have seen aren't your normal Hypoid gears.

CRW

[ September 25, 2003, 02:54 AM: Message edited by: Christopher R. Wise ]

 

[Dave]

Thanks for all the input guys. Seems like the consensus for oils in a transaxle is:

Run GL-5 if recommended. If synchros start acting up, run a high quality GL-4 (like Redline's MT-90) since you're going to have to tear the transaxle out anyway to replace the synchros.

I seem to remember my last car ('96 Camry FWD with manual transaxle) requiring a GL-4/5 oil as well so obviously some manufactures think a GL-4 is OK.

 

[pgtr]

I'm not entirely sure there can ever be much of a consensus for transaxles - the debate has been around for a long time - I can remember it back w/ Pantera guys and Getrag transaxles I think and I'm sure it predates that. Transaxles potentially can have to semi-mutually-exclusive features in a hypoid ring/pinion gear set AND synchros all sharing the same lubricant.

My own traditional 'consensus' in the absence of any manufacturer recomendations or info from experts on the specific transaxle is a 'combo' GL4/5 fluid. But again that's only generic. As CRW alludes to, there are a lot of possibilities here based on the design and manufacturer... Also his mention of the RL recommendation is pretty interesting - they usually just recommend whatever product equates to the manufacturer recomendation - here they are recommending their 'MT' lubricants instead.

Good luck!