75W-85W Correct Lube Spec ?

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My 1994 Mitsubishi specifies either a 75W-85W or 75W-90 GL-4 for the transaxle. I am questioning if the 75W-85W is a misprint since there are 2 low temperature viscosity numbers . Should the correct spec be 75W-85.
 
I am partially answering my own question. Yes, there is a 75W-85W grade gear lube. It would seem there are different low temperature points for measuring each viscosity. From the viscosity chart 85 W does not seem to be much lower in viscosity at 100 C when approximating where 85 would be.. So, I am wondering if it is OK to run a 75W-85 GL-4 oil for better high ambient temp protection. Viscosity would be between the 2 spec oils. I live in the eastern US.
 
GL-4 is what your maker is trying to get at, where 75w-85w is a common GL-4 while most GL-5 seem to be 75w-90 or 75w-140. My 5 speed nominally uses a synthetic GL-4, Castrol Syntorq, which Dodge and GM carry as a part number or Standard Transmission carries as Syntorq. I use M1 GL-5 75w-90 in the axles.
 
I have a 5 speed 96 Geo Metro that calls for 75w-85 or 75w-90 Castrol syntorq, which is absolutely impossible to find. If you can find it, get ready to shell out nearly 100 dollars for the gallon.

My Geo OM states that GM synchromesh is the recommended equivalent. So I opted for the much less expensive alternative, Pennzoil Synchromesh, available at AutoZone for $6.49/qt.
 
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There is debate over the use of Pennzoil Sychromesh on several other car forums. 3si.org has done several oil analysis and transaxle teardowns using this oil. While shifting is much improved, trans teardown showed more wear. Some users have noticed trans problems with long running and/or higher temps. I have looked at the Pennzoil label and it is not API rated, viscosity grade is 80W (web site) and the application is only for certain GM and Chryslers. That concerns me. But if it is recommended for your car - go for it, I does improve shifting.
 
I still have my 1996 3000GT`s owner`s manual and it says the same thing. 75W85W or 75W90 GL4. Then it has an oil table with 5W30-10W30 (non turbo) and 10W30-20W50 (turbo).

Get some Amsoil MTG 75W90 GL4. Your DSM will love it! Contact Pablo on this site.
 
http://quad4x4.com/NV4500FAQ.htm#when

Castrol Syntorq LT® 75w85w GL-4 rated, low temperature, synthetic gear lubricant is the only factory approved lubricant for NV4500 series transmissions. Some other lubricant manufacturers such as Amsoil may have products that are compatible. However, we have yet to see any other lubricant match the specifications of Syntorq LT®.

Castrol Syntorq LT® is available in quart bottles from Dodge dealers (p/n 4874459) and GM dealers (p/n 12346190). Castrol distributors offer factory sealed 16 gallon drums, plus some repackage the oil in 5 gallon pails. We sell Syntorq LT® in two quart jugs.
 
I've been reading more about it too, now that its in my tranny.

If a 2qt jug would fill my tranny, I'd probably buy some of the syntorq LT. But whoever decided to bottle it in 2 qt jugs, made a blunder. I'd have to purchase 4 qts total and pay astronomical shipping. No thanks.

I may decide to dump the PZ synchromesh and go with either Amsoil MTG or Red Line MT-90.
I think the cSt of the latter 2 is what I need, especially with the temps here in south Louisiana.

Mr. Molakule has stated that to me several times. Looks like I'll probably take his advice.
 
Quote:
GL-4 is what your maker is trying to get at, where 75w-85w is a common GL-4 while most GL-5 seem to be 75w-90 or 75w-140. My 5 speed nominally uses a synthetic GL-4, Castrol Syntorq, which Dodge and GM carry as a part number or Standard Transmission carries as Syntorq. I use M1 GL-5 75w-90 in the axles.


Well, let's examine the industry again.

GL4 does NOT refers to any specific viscosity, but it refers to a level of AW/EP protection for the gearing and bearings in a transmission.

A GL4 Manual Transmission Lubricant (MTL) can be any viscosity from 7.0 cSt (an ATF equivalent viscosity) to a 75W90 type viscosity 12.8 to 14.5 cSt, and contains special friction modification additives for synchro engagement.

A synchromensh fluid usually refers to a specialized fluid that contains special friction modification additives for transmissions that use mechanical synchronizer assemblies; those synchronizer assemblies amy be made of carbon fiber composites, sintered metal, brass/bronze, or steel-steel materials.

Current MTL GL4 viscosites are:

1. ATF Series-Type; 7.0 cSt (Equivalent to ATF viscosity; Note: ATF additive package is weak compared to most GL 4's)
2. Synchromesh Series-Type; 9.3 - 9.5 cSt (such as Texaco's MTL, Pennzoil's Synchromesh, GM and Chrysler's Synchromesh)
3. 75W85 Series-Type; 9.8 to 11.5 cSt (Amsoils MTF, Redline's MTL, RP's Synchromax LT, Nissan's MTL, Honda MTL, Castrol Syntorq LT)
4. 75W90 Series-Type; 12.8 to 14.5 cSt (Amsoil's MTG, Redline's MT-90).
 
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I`ve used Redline MT90 and now use Amsoil MTG and the Amsoil MTG is superior over the MT90 in my car. The most impressive quality about the MTG I`ve noticed is the shifting quality gets better the hotter the tranny gets. When I used MT90,shifting got really stiff and notchy as the tranny got good and hot. I was talking to a 240SX owner the other day and he had the same effects with MT90,BUT he now uses Mobil 1 75W90 GL5 (which Mobil doesn`t even recommend) and he loves it! Me,I`ll just stick with MTG from now on.
 
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This line should state:

1. ATF Series-Type; 6.5 to 8.5 cSt (Equivalent to ATF viscosity; Note: ATF additive package is weak compared to most GL 4's)
 
Originally Posted By: MolaKule

Current MTL GL4 viscosites are:

1. ATF Series-Type; 7.0 cSt (Equivalent to ATF viscosity; Note: ATF additive package is weak compared to most GL 4's)
2. Synchromesh Series-Type; 9.3 - 9.5 cSt (such as Texaco's MTL, Pennzoil's Synchromesh, GM and Chrysler's Synchromesh)
3. 75W85 Series-Type; 9.8 to 11.5 cSt (Amsoils MTF, Redline's MTL, RP's Synchromax LT, Nissan's MTL, Honda MTL, Castrol Syntorq LT)
4. 75W90 Series-Type; 12.8 to 14.5 cSt (Amsoil's MTG, Redline's MT-90).


Any idea what the viscosity range is for 75W-85W ? Is the Bobtheoilguy viscosity chart out of date? The ranges don't seem to match (it does not include the recent SAE 110 grade). Or am I reading the chart wrong.?

What is the design goal for specifying an oil with two low temp grades such as 75W-85W? Is this just to have a finer difference in the viscosity cSt ?
 
Most charts, including BITOG's chart, is focused on motor oils and differential gear lubes.

And it shouldn't match.

MTL specific lubes we're developed for manual tranny's and transaxles, and not for differentials or industrial gear boxes.


Quote:
3. 75W85 Series-Type; 9.8 to 11.5 cSt (Amsoils MTF, Redline's MTL, RP's Synchromax LT, Nissan's MTL, Honda MTL, Castrol Syntorq LT)
 
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Quote:
What is the design goal for specifying an oil with two low temp grades such as 75W-85W? Is this just to have a finer difference in the viscosity cSt ?


It is kind of splitting hairs, but I think the "W" suffixes were possibly meant to convey slightly better low temp performance specs and possibly lower pour points.
 
There is an inconsistent use of 'GL-4' as Pennzoil doesn't use the term to describe their Synchromesh, although it might be implied from other specs. The only candidate in their line for a Castrol Syntorq replacement would be the synthetic GL-4, but since GM and Dodge both seem to specifially state Syntorq in some cases when not using their OEM part number I'll stick with Syntorq.

http://www.pennzoil.com/products/gear_oil/index.html#syn_gear7590

Pennzoil® Synthetic Gear Oils 75W-90 GL-4 and GL-5

Pennzoil® Synchromesh Fluid

Pennzoil® Gearplus® SAE 80W-90 GL-5

Pennzoil® Gearplus® SAE 80W-90 GL-4

Pennzoil® Gearplus® SAE 80W-140 GL-5
 
Molakule, I respect your knowledge and I have heard you referred to as "legendary" on here and other forums.
On another forum I read where somebody used some of your "special sauce" for their tranny, or maybe it was the engine.

Do you make a specific manual tranny fluid that can be purchased?

Sorry if I'm totally mistaken here.
 
Originally Posted By: 1sttruck
There is an inconsistent use of 'GL-4' as Pennzoil doesn't use the term to describe their Synchromesh, although it might be implied from other specs. The only candidate in their line for a Castrol Syntorq replacement would be the synthetic GL-4, but since GM and Dodge both seem to specifially state Syntorq in some cases when not using their OEM part number I'll stick with Syntorq.

http://www.pennzoil.com/products/gear_oil/index.html#syn_gear7590

Pennzoil® Synthetic Gear Oils 75W-90 GL-4 and GL-5

Pennzoil® Synchromesh Fluid

Pennzoil® Gearplus® SAE 80W-90 GL-5

Pennzoil® Gearplus® SAE 80W-90 GL-4

Pennzoil® Gearplus® SAE 80W-140 GL-5



Those Pennzoil gear oils are hard to find!
 
1sttruck,

You're still missing certain salient points on the topic of mtl's.

Selection of mtl specific oils have three main factors to consider:

1. proper viscosity for loads, internal gear speeds, cooling, and shifter fork operation

2. proper AW/EP package to protect bearings and gears,

3. proper friction modification for synchro synchronization

I can assure you the Pennzoil® Synchromesh Fluid has a GL4 protection rating, but the viscosity of Pennzoil® Synchromesh Fluid may not be correct for your transmission design.

The synthetic and non-synthetic Gearplus® series are meant for differentials and Marine lower units .

I suspect number three (3) in the list is most appropriate for your unit that specifies 75W85W;


Quote:
3. 75W85 Series-Type; 9.8 to 11.5 cSt (Amsoils MTF, Redline's MTL, RP's Synchromax LT, Nissan's MTL, Honda MTL, Castrol Syntorq LT)
 
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Originally Posted By: MolaKule
Most charts, including BITOG's chart, is focused on motor oils and differential gear lubes.

And it shouldn't match.

MTL specific lubes we're developed for manual tranny's and transaxles, and not for differentials or industrial gear boxes.


Quote:
3. 75W85 Series-Type; 9.8 to 11.5 cSt (Amsoils MTF, Redline's MTL, RP's Synchromax LT, Nissan's MTL, Honda MTL, Castrol Syntorq LT)


Ok, would it be correct to say that there is now an MTL spec chart for viscosity, temp and SAE grades, and they do not have a correlation to SAE gear lubes ( or AGMA ) in the past?
 
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