Transmission Grind

[fliprayzin240sx]

K im stumped, somebody explain this to me. My SR tranny started grinding 3rd gear after changing to RP 75-90W. Well the funny thing is that it only does it when the tranny gets hot. When its cold, the shit shifts like butter. So I figured, oil might be too thin, so I dropped a QT out and replaced it with RP 75-140W. Doesnt do it as bad when warm but still does it. Didnt see any shaving when I dropped some of the oil out, drain plug had no shavings what so ever. So my question is, if my synchros are bad, WHY THE FUCK DOES IT SHIFT GREAT COLD?!?!





PS: FUCK RP, I got AMSOIL on the way...

[Bigsyke]

RP is the exact reason. Im pretty sure the owner of my tranny used RP and when I removed the drain plug for the 1st time it was a mushroom cloud of metal shavings. The owner said the tranny grinded in most gears.

Put some amsoil in and it shifts like new.

[lazysk8er2]

needs gl4 boyeeeee

[Bigsyke]

GL5 wont cause a grind. Pretty sure you can use a GL5 if its marked yellow safe.

My amsoil is GL5

[lflkajfj12123]

supposed to use gl4 for the transmission since synchros are made of copper or something like that

flip

it should be all good once you get all the rp out

its just too thin when its going through the heat cycle

amsoil will fix you right up

if still a little bit of grinding you can just double clutch to third

i usually double clutch into second on the ka

[S14DB]

My amsoil is GL5
Then you got the wrong one.

AMSOIL - Synthetic Manual Transmission and Transaxle Gear Lube 75W-90 (MTG) (http://www.amsoil.com/storefront/mtg.aspx)
Meets GL-4 performance specifications required by some models of Acura, Hyundai, Infiniti, Kia, Land Rover, Lexus, Mazda, Mitsubishi, Nissan, Subaru, Suzuki, Toyota, Volkswagen, Hino Mitsubishi-Fuso, and Zetor. Ideal for muscle car transmissions such as Muncie, Borg Warner, Saginaw, Ford Toploader, Dearborn and New Process. Also recommended for Gear Vendors Gear Splitters.

[Bigsyke]

Yes I think I did. Im reading the specs on the gear lube and the transaxle gear lube, are they really much different?

http://www.amsoil.com/storefront/fgr.aspx

Thats the only thing napa had....crap.

but wait;


Use AMSOIL Extended Drain Synthetic Gear oils in differentials, manual transmissions or other gear applications where one or more of the following standards are specified: API GL-5 & MT-1, MIL-PRF-2105E, Dana SHAES 234 (Formerly Eaton PS-037) for 250,000 miles, Dana SHAES 256 (Formerly Eaton PS-163) for 500,000 miles, Mack GO-J & GO-J+, Meritor 0-76N (75W-90) & 0-80 (80W-140), and Navistar TMS 6816 plus hypoid gear oil specifications from all foreign and domestic manufacturers such as GM, Ford and Daimler Chrysler. Can also be used in rear axles where API Service GL-4 lubricant is recommended.


So it should be yellow safe?

[Donedreamin]

Can GM's synchro mesh be used , effectively if a gear is already grinding?

[S14DB]

Yes I think I did. Im reading the specs on the gear lube and the transaxle gear lube, are they really much different?

AMSOIL - Long Life Synthetic Gear Lube SAE 75W-90 (FGR) (http://www.amsoil.com/storefront/fgr.aspx)

Thats the only thing napa had....crap.

but wait;



So it should be yellow safe?
No, it's safe for our Differentials that use GL-4. Most GL-4 Differentials can run GL-5 cause there is no "yellow metal"(Sycros or block rings).
Can GM's synchro mesh be used , effectively if a gear is already grinding?
No, synchromesh is a different oil weight.

[Donedreamin]

So just so i know, i CANT use it?

[Bigsyke]

may sound noobish, but can I use it untill I get an order of the correct amsoil in? (aka a week or so)

[fliprayzin240sx]

Yes I think I did. Im reading the specs on the gear lube and the transaxle gear lube, are they really much different?

AMSOIL - Long Life Synthetic Gear Lube SAE 75W-90 (FGR) (http://www.amsoil.com/storefront/fgr.aspx)

Thats the only thing napa had....crap.

but wait;



So it should be yellow safe?

I almost did the same shit, they only had gear lube on island. I returned it yesterday after I somebody pointed it out to me. I just ordered MT oil just to be sure.

[JRas]

Yes I think I did. Im reading the specs on the gear lube and the transaxle gear lube, are they really much different?

AMSOIL - Long Life Synthetic Gear Lube SAE 75W-90 (FGR) (http://www.amsoil.com/storefront/fgr.aspx)

Thats the only thing napa had....crap.

but wait;



So it should be yellow safe?

sounds like you should be fine.

I use Redline MT-90 ( GL-4 ) It's not very good cold, but when it warms up it feels golden.

[slider2828]

Well guys, just to have ACTUAL usage review. I actually have used BOTH Amsoil GL4 (transmission and transaxle) and GL5 (Sever Gear Oil).

GL5 - It feels good both cold and hot. (I have been on the track and no problems)

GL4 - Much improved, better shifting for sure than the GL5 especially when warm.

He flyp, I also had the shifting problem you are describing, but only at 7000RPM shifting, (feels fine on the street) and in less than 2 weeks my slave cylinder blew out. Get a new one and replace. Mine wasn't leaking either when it blew out. Now I have a Tokico and its better and do a clutch line flush as well.

I think this with GL-4 will help and noticeably better than GL-5. I have used MT90 and Whatever blah... MT90 is junk.... get rid of it....

[Bigsyke]

Good to hear.

Im still concered about the gear lube vs the transaxle oil. Both are the same weight.

Ive read around the amsoil gear lube has slightly more detergents (EP) than the transaxle oil.

[Tom25666]

when I got my invoice for my motor swap, it says they used 75W-90 Severe Gear Amsoil MTG-01 and I have the same problem, only it is 2nd gear. Shifts fine when cold, then after about 10 minutes, grinds the shit out of 2nd.

[slider2828]

Mine didn't grind at all on the Amsoil unlike MT90 from Redline. never did.... Only grind would be around 7200 RPM shifting, but I think that is because the RPM doesn't match cause of the lightened flywheel, steel shaft, and probably a slave cylinder that was going out.

[Bigsyke]

TYPICAL TECHNICAL PROPERTIES
AMSOIL Long Life Synthetic Gear Lube 75W-90 (FGR)
Kinematic Viscosity @ 100°C, cSt (ASTM D-445) 15.9
Kinematic Viscosity @ 40°C, cst (ASTM D-445) 122.6
Viscosity Index (ASTM D-2270)138
Brookfield Viscosity, cP (150,000 Max)92,325 @ -40°C
Flash Point, °C (°F) (ASTM D-92) 150°C Min.212 (414)
Pour Point, °C (°F) (ASTM D-97)-51(-67)
Copper Corrosion (ASTM D-130) 1b Max @ 121 °C (250°F) / 3hr 1b
Falex Procedure B (ASTM D-3233) (failure load, lbf.)1500
Foam Stability (ASTM D-892) (20/50/20 maximum)0/0/0


TYPICAL TECHNICAL PROPERTIES
Synthetic Manual Transmission and
Transaxle Gear Lube 75W-90 API GL-4 (MTG)
Kinematic Viscosity @ 100°C, cSt (ASTM D-445) 14.7
Kinematic Viscosity @ 40°C, cst (ASTM D-445) 84.5
Viscosity Index (ASTM D-2270)181
Flash Point, °C (°F) (ASTM D-92) 150°C Min.204 (399)
Pour Point, °C (°F) (ASTM D-97)-46 (-51)
4-Ball Wear 75°C, 1200 rpm, 40kg, 1 hr.0.45mm
Brookfield Viscosity @ -40°C44,200
Foam Stability (ASTM D-892) (20/50/20)0/0/0
Copper Corrosion (3 hr, 121°C) (ASTM D-130)1B

[Bigsyke]

TYPICAL TECHNICAL PROPERTIES


AMSOIL Long Life Synthetic Gear Lube 75W-90 (FGR)



Copper Corrosion (ASTM D-130) 1b Max @ 121 °C (250°F) / 3hr 1b




TYPICAL TECHNICAL PROPERTIES
Synthetic Manual Transmission and

Transaxle Gear Lube 75W-90 API GL-4
(MTG)




Copper Corrosion (3 hr, 121°C) (ASTM D-130)1B




Just read around BITOG. It seems that if the gear oil passes the ASTM D-130 (aka a 1a or 1b) it will NOT harm a copper strip and thus they have the exact same ammount of sulpher


Synchromesh Manual Transmission lubes we're developed specifically for manual transmissions and transaxles, and not for differentials or industrial gear boxes.

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

Most Differential and Manual Transmission oils contain sulfur-phosphorous EP packages. GL4-rated oils usually contain about 40% to 60% of the amount of Differential lubricant EP’s. Therefore, both MT and Differential lubes contain the same EP additives, just in different strengths or additive ratios.

GL4 does NOT refer to any specific viscosity, but it refers to a level of AW/EP protection for the gearing and bearings in a transmission, so GL4 has come to infer a gear lube with the above percentages of EP additive. The exception of course is ATF fluid used in some of the newer transmissions.

Both differential and manual transmission fluids use chemical compounds that subdue or inhibit the corrosive effects of sulfur and phosphorous such as calcium, magnesium, boron, potassium or other basic compounds. Emulsifiers, corrosion and rust inhibitors also are included to do their respective jobs.

Differential lubes use friction modifiers to reduce mechanical and fluid friction and add some anti-shudder friction modifier for limited slip; both very different chemical compounds.

Manual Transmission fluids use a different friction modifier specifically designed for synchro engagement, a modifier that does NOT contain the same chemical compounds as do differential lubes.

Ever since the synchromesh-type fluids appeared on the scene (such as the GM Synchromesh fluid), drivers have had better shifting due to better synchro engagement, attributed to the specialized friction modifier used in these lubes. This specialized friction modifier is better for metallic and composite synchros in terms of shifting and life.

You also have to consider the viscosity of the fluid that the transmission was designed for. The spectrum now ranges from ATF to 75W90 viscosities and therefore a synchromesh GL4 Manual Transmission Lubricant (MTL) can be any viscosity from 7.0 cSt (ATF equivalent viscosity) to a 75W90 type viscosity of approx. 14.5 cSt, and contains special friction modification additives for synchronizer assembly engagement.

Current MTL GL4 viscosities are:

1. ATF viscosity Series; 6.5 to 8.5 cSt (Equivalent ATF viscosity; Note: ATF additive package is weak compared to most GL4's)

2. Synchromesh viscosity Series; 9.3 - 9.6 cSt (such as Amsoils MTF, Texaco's MTL, Pennzoil's Synchromesh, GM and Chrysler's Synchromesh)

3. 75W85 viscosity Series; 9.8 to 11.5 cSt ( Redline's MTL, RP's Synchromax LT, Nissan's MTL, Honda MTL, Castrol Syntorq LT)

4. 75W90 viscosity Series; 12.8 to 14.5 cSt (Amsoil's MTG, Redline's MT-90).

A differential lube may not kill your manual transmission in your light truck or car, but it is not the optimum lube for it. A differential 75W90 (GL5) lubricant usually has a higher viscosity than does an mtl in the same advertised weight.

Many if not most GL5 fluids rated for differentials may also be rated as MT-1. Some manufacturers, such as Amsoil®, state the following:

“Recommended for use in differentials, manual transmissions and other gear applications requiring any of the following specifications: API GL-5, MT-1, MIL-PRF-2105E, Dana SHAES 234 (Formerly Eaton PS-037), Mack GO-J, or the differential (hypoid) gear oil specifications from all domestic and foreign manufacturers such as GM, Ford and Daimler Chrysler. Can also be used in axles where an API GL-4 lubricant is recommended.”

This MT-1 rating refers to use in heavy duty truck transmissions, and as such, does NOT necessarily mean that this fluid will function properly in a light truck or car synchromesh transmission.

[S14DB]

I think the key points are:

Both differential and manual transmission fluids use chemical compounds that subdue or inhibit the corrosive effects of sulfur and phosphorous such as calcium, magnesium, boron, potassium or other basic compounds. Emulsifiers, corrosion and rust inhibitors also are included to do their respective jobs.

Differential lubes use friction modifiers to reduce mechanical and fluid friction and add some anti-shudder friction modifier for limited slip; both very different chemical compounds.

Manual Transmission fluids use a different friction modifier specifically designed for synchro engagement, a modifier that does NOT contain the same chemical compounds as do differential lubes.
A differential lube may not kill your manual transmission in your light truck or car, but it is not the optimum lube for it. A differential 75W90 (GL5) lubricant usually has a higher viscosity than does an mtl in the same advertised weight.

[n_my_coupe]

this thread has been very helpful....thank all of you peoples... :)