Please help me find the best T-Case fluid

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This request is for a 93 DSM (Eagle Talon TSI AWD Turbo/Mitsubishi Eclipse GSX/Plymouth Laser). If you weren't already aware, these vehicles are generally heavily modified and for performance use. This project is the opposite. It will see stock boost and light duty. The objective is maximum fuel economy as opposed to my other regularly tracked DSM. The stock spec per the owner's manual is: ""Hypoid gear oil, SAE 75W/8OW conforming to API classification GL-4 or higher" I'd like to stick as closely to this specification for this project. I need just a quart of something or other. I have a quart of MT-85 (GL4) laying around, MTL (GL4 seems to be 75-80), and Pennzoil Synchromesh. I think that the MTL is closest to the spec I am looking for, but wouldn't a GL5 be more slippery? What about the Pennzoil Synchromesh? I know that the additives won't help in a T-case, but would they hurt anything? That is the lightest mainstream fluid that I can think of that is still somewhat generally purposed. Still none of these are "hypoid" gear oil as far as I know which still has me a bit worried. Redline's site states "MTL, MT-85 & MT-90 are not for use in differentials with hypoid gears" P.S. - Here is a description of the T-Case setup for the racing world: "89-94 DSM: The 89-99 DSMs used a spiral bevel gearset in the transfer case. The recommended oil for all transfer cases in the Mitsubishi DSMs GL-5 90w Hypoid gear oil." http://www.teamrip.com/transfer_case_hypoid_gear_oil_recommendation_info.html Thanks for any input!
 
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MolaKule

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It sounds as if is speced for a GL-5 rated 75W90 differential lube, since the torque transferred by the spiral bevel gears may be higher than for a manual transmission. Redline 75W90, Ansoil SevereGear, Mobil 1, etc. in 75W90 should work.
Quote:
... MTL (GL4 seems to be 75-80)...
This a common misconception:
Quote:
We should emphasize again that the GL-4 rating for gear lubes is primarily a gear and bearing protection rating for systems that are not as heavily loaded as those found in hypoid differentials or Heavy Duty truck transmissions.
The 7XWYY numbers are for the viscosity rating and not the protection rating.
 

dx92beater

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Originally Posted By: MolaKule
It sounds as if is speced for a GL-5 rated 75W90 differential lube, since the torque transferred by the spiral bevel gears may be higher than for a manual transmission. Redline 75W90, Ansoil SevereGear, Mobil 1, etc. in 75W90 should work.
Quote:
... MTL (GL4 seems to be 75-80)...
This a common misconception:
Quote:
We should emphasize again that the GL-4 rating for gear lubes is primarily a gear and bearing protection rating for systems that are not as heavily loaded as those found in hypoid differentials or Heavy Duty truck transmissions.
The 7XWYY numbers are for the viscosity rating and not the protection rating.
I am sorry, but I meant to specify that MTL is 75W80 and is also GL4. I didn't mean to imply that 75W-80 is synonymous with the term GL4. How do you figure that the specs for the t-case are a GL5 75W-90 when the manual clearly states "Hypoid gear oil, SAE 75W/8OW conforming to API classification GL-4 or higher". The link that I provided was not the spec. It was a recommendation. Really want to push things to the ragged edge as far as how slippery the fluid is in the name of fuel economy even if slightly over reliability. This is just a hobby. GL5 seems more fuel economy oriented as compared to GL4. The question is, would a 75W-90 GL5 provide for better fuel economy than a 75W-90 GL4 fluid? Thanks
 
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MolaKule

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Originally Posted By: dx92beater
Originally Posted By: MolaKule
It sounds as if is speced for a GL-5 rated 75W90 differential lube, since the torque transferred by the spiral bevel gears may be higher than for a manual transmission. Redline 75W90, Ansoil SevereGear, Mobil 1, etc. in 75W90 should work.
Quote:
... MTL (GL4 seems to be 75-80)...
This a common misconception:
Quote:
We should emphasize again that the GL-4 rating for gear lubes is primarily a gear and bearing protection rating for systems that are not as heavily loaded as those found in hypoid differentials or Heavy Duty truck transmissions.
The 7XWYY numbers are for the viscosity rating and not the protection rating.
I am sorry, but I meant to specify that MTL is 75W80 and is also GL4. I didn't mean to imply that 75W-80 is synonymous with the term GL4. How do you figure that the specs for the t-case are a GL5 75W-90 when the manual clearly states "Hypoid gear oil, SAE 75W/8OW conforming to API classification GL-4 or higher". GL5 seems more fuel economy oriented as compared to GL4. The question is, would a 75W-90 GL5 provide for better fuel economy than a 75W-90 GL4 fluid? Thanks
The reason being is they use the words "hypoid" and "GL-4 or higher" which tells me that even though they are using spiral bevel gears in the TC, they are expecting high torque transfer through the gears, hence a GL-5 protection rating.
Quote:
The question is, would a 75W-90 GL5 provide for better fuel economy than a 75W-90 GL4 fluid?
A GL-4 dedicated manual transmission fluid has a lower viscosity than does a GL-5 rated differential lube, so no, just the opposite. If you want Max wear protection for the TC, then stick with a GL-5 fluid.
 
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dx92beater

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Originally Posted By: MolaKule
Originally Posted By: dx92beater
Originally Posted By: MolaKule
It sounds as if is speced for a GL-5 rated 75W90 differential lube, since the torque transferred by the spiral bevel gears may be higher than for a manual transmission. Redline 75W90, Ansoil SevereGear, Mobil 1, etc. in 75W90 should work.
Quote:
... MTL (GL4 seems to be 75-80)...
This a common misconception:
Quote:
We should emphasize again that the GL-4 rating for gear lubes is primarily a gear and bearing protection rating for systems that are not as heavily loaded as those found in hypoid differentials or Heavy Duty truck transmissions.
The 7XWYY numbers are for the viscosity rating and not the protection rating.
I am sorry, but I meant to specify that MTL is 75W80 and is also GL4. I didn't mean to imply that 75W-80 is synonymous with the term GL4. How do you figure that the specs for the t-case are a GL5 75W-90 when the manual clearly states "Hypoid gear oil, SAE 75W/8OW conforming to API classification GL-4 or higher". GL5 seems more fuel economy oriented as compared to GL4. The question is, would a 75W-90 GL5 provide for better fuel economy than a 75W-90 GL4 fluid? Thanks
The reason being is they use the words "hypoid" and "GL-4 or higher" which tells me that even though they are using spiral bevel gears in the TC, they are expecting high torque transfer through the gears, hence a GL-5 protection rating.
Quote:
The question is, would a 75W-90 GL5 provide for better fuel economy than a 75W-90 GL4 fluid?
A GL-4 dedicated manual transmission fluid has a lower viscosity than does a GL-5 rated differential lube, so no, just the opposite. If you want Max wear protection for the TC, then stick with a GL-5 fluid.
Thanks, learned something new. MTL it is then to meet this hobbyist objective.
 
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Use a GL5 in your rear diff and transfer case. Go thinner and/or full synth for more mpg. Try: http://www.redlineoil.com/product.aspx?pid=40&pcid=4 Ford, GM, Toyota, Honda, Driven... also have GL5 75w85 hypoid gear oils. There are also 75w80 GL5 gear oils if you want thin as possible in the xfer case and rear diff. Use the GL4 in the manual transmission. Amsoil MTF, Redline MTL, BG Syncroshift,... are about as thin as I would go for GL4. But with an MPG quest, Ravenol, Pentosin, and OE Castrol BOT fluids can be had in the 6-7.5cst range. Royal Purple Synchromax is another. Lubegard can also be added. [url= http://www.lubegard.com/~/C-269/LUBEGARD+Gear+Fluid+Supplement]Lubegard Gear[/url]
 

dx92beater

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Originally Posted By: Greasymechtech
Use a GL5 in your rear diff and transfer case. Go thinner and/or full synth for more mpg. Try: http://www.redlineoil.com/product.aspx?pid=40&pcid=4 Ford, GM, Toyota, Honda, Driven... also have GL5 75w85 hypoid gear oils. There are also 75w80 GL5 gear oils if you want thin as possible in the xfer case and rear diff. Use the GL4 in the manual transmission. Amsoil MTF, Redline MTL, BG Syncroshift,... are about as thin as I would go for GL4. But with an MPG quest, Ravenol, Pentosin, and OE Castrol BOT fluids can be had in the 6-7.5cst range. Royal Purple Synchromax is another. Lubegard can also be added. [url= http://www.lubegard.com/~/C-269/LUBEGARD+Gear+Fluid+Supplement]Lubegard Gear[/url]
I just missed this post. Ended up running MTL 75-80 GL4 in the T-CASE with one tiny lick of Synchromesh....(didn't have enough MTL laying around so I had to top it off with a tiny bit of Synchromesh). Thanks for the info. Here are the specs on the rear BTW. Looks like GL5 is mandatory for the rear. Above -23°C (-10°F): SAE 90, 85W-90, 8OW-90 From -34°C (-30°F) to -23°C (-10°F): SAE 8OW, 8OW-90 Below -34°C (-30°F): SAE 75W Suggestions on the rear now? 75-80 GL5 was mentioned but from where? I'd even do straight 75W if obtainable. Redline's site down right now, so I am having trouble getting ideas.
 
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Although my car is different, it still uses a similar transfer case. Mine called for Dia-Queen LS SAE90 GL-5. I first changed it out for VWB 80w90, and it worked fine. Later, I used RP 75w90. For the rear differential, it also called for the same Dia-Queen stuff, I used VWB 80w90 first, then used RP 75w90. I would never experiment with anything below an XXw90 oil, but if I was willing, I would look into Redline 75w85 GL-5. What are you using in your Galant VR-4? It is my understanding that they have a very similar drivetrain to the DSM.
 
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you will be hard pressed to beat Redlines lubes, except the price of course. check their web + put your vehicle in their application finder, otherwise call them + you will talk to a real person + get a professional recommendation. i use the MT-90 in my trannies + its great. Redline products are real synthetics of superior quality. the higher cost is because esters are the most expensive base lubricants to make
 

JHZR2

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Originally Posted By: oilboy123
I love Amsoil trans, and Severe gear oil........ harder to get, but worth it.
+1. I've found that redline gives good initial feel, but shift quality degrades faster. Amsoil mtf and diff lube stay consistently good.
 
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