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What weight is best? #4710006
03/28/18 07:16 PM
03/28/18 07:16 PM
Joined: Dec 2012
Posts: 51
Connecticut
Mar57 Offline OP
Mar57  Offline OP
Joined: Dec 2012
Posts: 51
Connecticut
The car is a Mazda Miata. Owners manual calls for 90wt. gear lube in the diff. I can't find any straight 90wt. lubes. So the question is can I use a 75-90wt. lube? Mobil 1, Valvoline etc. make a synthetic 75-90wt. and a synthetic would be my preference if that weight can be used. What do you guys think?

Re: What weight is best? [Re: Mar57] #4710016
03/28/18 07:22 PM
03/28/18 07:22 PM
Joined: May 2010
Posts: 9,463
out there
spasm3 Offline
spasm3  Offline
Joined: May 2010
Posts: 9,463
out there
I would check what the dealer has. If its 75-90 or 80w90 as well, then use what you want. If they have a straight 90wt( i doubt it) buy that.


13 elantra 72k 5w30 QSUD
03 chevy avalanche 80k synpwr 5w30
17 mazda cx-5 7300 miles m1 0w30
Re: What weight is best? [Re: Mar57] #4710037
03/28/18 07:34 PM
03/28/18 07:34 PM
Joined: Jun 2003
Posts: 17,815
Deplorable in apple valley, ca
Chris142 Online content
Chris142  Online Content
Joined: Jun 2003
Posts: 17,815
Deplorable in apple valley, ca
Any 75w90 or 80w90 is fine.


02 Wrangler carlube 5w30
87 F250 traveler 15w40
07 fjcruiser Chevron 10w30
Z400 castrol T 10w40
Can am maveric edge 5w40
57 case tractor 15w40
Re: What weight is best? [Re: Mar57] #4710052
03/28/18 07:55 PM
03/28/18 07:55 PM
Joined: Sep 2005
Posts: 5,909
MIchigan
Warstud Offline
Warstud  Offline
Joined: Sep 2005
Posts: 5,909
MIchigan
Originally Posted By: Mar57
Owners manual calls for 90wt.


They don't mean straight 90wt.

Re: What weight is best? [Re: Mar57] #4710058
03/28/18 08:05 PM
03/28/18 08:05 PM
Joined: Dec 2012
Posts: 51
Connecticut
Mar57 Offline OP
Mar57  Offline OP
Joined: Dec 2012
Posts: 51
Connecticut
"They don't mean straight 90wt."

If they didn't mean it, why print it? That's what the manual says so why should someone have to try to interpret what they mean?

Re: What weight is best? [Re: Mar57] #4710064
03/28/18 08:17 PM
03/28/18 08:17 PM
Joined: Aug 2012
Posts: 3,041
Cincinnati
donnyj08 Offline
donnyj08  Offline
Joined: Aug 2012
Posts: 3,041
Cincinnati
Any 75w90 synthetic will do.


2008 Silverado Z71 LT 90k Maxlife FS 5w30
2010 Ford Escape 172k QSUD 5w20
2016 Yamaha XSR900 12k, Rotella 15w40 Yamaha Filter.
Re: What weight is best? [Re: Mar57] #4710066
03/28/18 08:18 PM
03/28/18 08:18 PM
Joined: Sep 2005
Posts: 5,909
MIchigan
Warstud Offline
Warstud  Offline
Joined: Sep 2005
Posts: 5,909
MIchigan
They mean 75w90 or 80w90 and not 75w140. I'm using these as examples because there the most common.

Re: What weight is best? [Re: Mar57] #4710067
03/28/18 08:18 PM
03/28/18 08:18 PM
Joined: Jun 2004
Posts: 244
Athens, GA
ctechbob Offline
ctechbob  Offline
Joined: Jun 2004
Posts: 244
Athens, GA
Agreed, never had a lubrication caused problem out of a 75w-90 or 80w-90 in my 91, even with the 1/2qt capacity and the track beatings it took.


2008 Acura TL Type S - 154k
2003 Honda Accord V6 - 207k
2000 Honda Accord I4 - 311k
Current Oil - Milesyn SXR5W30
Current Filter - Partsmaster 61334
Re: What weight is best? [Re: Mar57] #4710105
03/28/18 09:20 PM
03/28/18 09:20 PM
Joined: Feb 2007
Posts: 338
Pennsylvania
Reggaemon Offline
Reggaemon  Offline
Joined: Feb 2007
Posts: 338
Pennsylvania
What year is the Miata? In the 3 owner manuals that I checked NA,NB and NC.
The specs were...GL-5 SAE 90 80w-90 and 75w-90.
Everyone I know is using 75w-90.

Re: What weight is best? [Re: Mar57] #4710252
03/29/18 06:33 AM
03/29/18 06:33 AM
Joined: Mar 2004
Posts: 21,114
Upstate NY
Donald Online content
Donald  Online Content
Joined: Mar 2004
Posts: 21,114
Upstate NY
Less weight is definitely best. I am trying to loose weight.


2015 Subaru Forester 2.5 engine/CVT
2015 Ford F250 w/Powerstroke
2016 Subaru Crosstrek CVT (wife's)
Re: What weight is best? [Re: Mar57] #4710321
03/29/18 08:01 AM
03/29/18 08:01 AM
Joined: Sep 2007
Posts: 8,598
Florida
artificialist Offline
artificialist  Offline
Joined: Sep 2007
Posts: 8,598
Florida
Many Japanese cars call for SAE 90 gear oil, but I never had a problem when replacing it with conventional 80w90 or synthetic 75w90. In the repair shops where I worked, we just used whatever XXw90 gear oil was on the shelf.


2010 Lancer Ralliart Sportback
Re: What weight is best? [Re: Mar57] #4710768
03/29/18 05:00 PM
03/29/18 05:00 PM
Joined: Jan 2017
Posts: 366
NJ
JLawrence08648 Offline
JLawrence08648  Offline
Joined: Jan 2017
Posts: 366
NJ
Always synthetic in that heavy weight oil, doesn't matter the weight as long as it's close, which it is.


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