I just drained the ST 80w90 and ARX that I put in my tercel's manual transmission about 1000 miles ago. Filled it with 2.5 quarts of Redline MT-90. Shifting is smooth, but now I think I know the word "notchy". The red line seemed thinner than the Supertech gear oil. Could this be why? What can I do to make it less "notchy"?
Not sure I like this Red Line MT-90
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I had the same experience with my Tacoma.
I tried RedLine MT-90 and noticed that I was starting to miss shifts and the transmission seemed notchy. I drained the RL and went with Amsoil and don't think I've missed a shift in over a year! There really is a difference in gear oils.
I tried RedLine MT-90 and noticed that I was starting to miss shifts and the transmission seemed notchy. I drained the RL and went with Amsoil and don't think I've missed a shift in over a year! There really is a difference in gear oils.
I had high hopes when first trying Redline D4, and MTL, but they weren't that great for shifting. Random notchiness occurred.
I'm happy with Pennzoil Synchromesh, now.
I'm happy with Pennzoil Synchromesh, now.
I, too, have noticed the "notchiness" of the MT-90 in my Nissan Hardbody 5-spd. I assumed it was the result of going to a 75W-90 synthetic instead of the 80W-90 dino that I had been running for the previous two years. I've never "missed" a gear or heard/felt any grinding, though.
All in all, I'm quite happy with the Redline.
All in all, I'm quite happy with the Redline.
I put Amsoil 75W90 in my Cherokee something like 2 years ago, and it shifts as smooth as an eel's a$$.
I could easily head down the street and get some pennzoil or mobil 1, but I dont really feel like placing another internet order for Red Line. Can I drain out about a quart of redline and add M1 or Pennzoil? Will mixing be a problem? I had planned on leaving this stuff in for the life of the car. The factory dino oil was in for 76K miles.
Make sure that the fluid is topped off. I found several vehicles low on fluid that were serviced with premeasured amounts. If more can be added without leaking out of the fill plug or vent(however level is checked), then add more.
I switched to MT90 in numerous Nissans with excellent long term results.
I guess that every transmission is different.
If the clutch cable/hydraulics are adjusted/bled correctly, and if the shifter bushings/linkages are OK, then definitely try another fluid.
I wouldn't bother with just wasting one quart and hoping a little top off, with another brand, will help.
The problem with synchromesh is that it is not acceptable for all applications. I have faith that it would work in place of ATF and motor oil. But, I wouldn't use it in place of a 90wt gear oil.
There are several GL4 safe 90wt gear oils(either GL4 only or GL5 stating GL4 safe):
Redline MT90
Amsoil AGT/ALU
OEM fluids(like genuine Nissan/Toyota....)
Royal Purple Maxgear
RenewableLube 80w90 gear rock oil
Quaker State Multipurpose GL4
Noco GLX gl4
Neo 75w90HD
It seems that almost every major oil company has a GL4 gear oil but availabity is scarce. You might need to call an oil distributor out of the yellow pages, or special order the quarts online or at the autoparts stores.
I also feel that some people confuse slow notchiness with clickness. I prefer the secure shifting of a 'quick click shift' compared to typical slow smooth shifts that some want. It might require a hair bit more effort, but MT90 shifts the best/fastest in my vehicles. No gear crunching here ever!
I switched to MT90 in numerous Nissans with excellent long term results.
I guess that every transmission is different.
If the clutch cable/hydraulics are adjusted/bled correctly, and if the shifter bushings/linkages are OK, then definitely try another fluid.
I wouldn't bother with just wasting one quart and hoping a little top off, with another brand, will help.
The problem with synchromesh is that it is not acceptable for all applications. I have faith that it would work in place of ATF and motor oil. But, I wouldn't use it in place of a 90wt gear oil.
There are several GL4 safe 90wt gear oils(either GL4 only or GL5 stating GL4 safe):
Redline MT90
Amsoil AGT/ALU
OEM fluids(like genuine Nissan/Toyota....)
Royal Purple Maxgear
RenewableLube 80w90 gear rock oil
Quaker State Multipurpose GL4
Noco GLX gl4
Neo 75w90HD
It seems that almost every major oil company has a GL4 gear oil but availabity is scarce. You might need to call an oil distributor out of the yellow pages, or special order the quarts online or at the autoparts stores.
I also feel that some people confuse slow notchiness with clickness. I prefer the secure shifting of a 'quick click shift' compared to typical slow smooth shifts that some want. It might require a hair bit more effort, but MT90 shifts the best/fastest in my vehicles. No gear crunching here ever!
Most frontwheel drives designed for world market have a detent type engaugement at the end of the shift stroke. This is by design! It should be smooth comeing out of the gear and the transition to the next gear should be smooth as well. If you get a naotch,click or detent type feel the last 1/8-1/4 inch that is normal in alot of fwd car transmissions. This is much more common today then it was uears ago.
What I [and maybe others] ,refer to as notchiness is more of a 'dry' feel to shifting.
I like fast and smooth, not slow and notchy shifts.
I like fast and smooth, not slow and notchy shifts.
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I had the exact opposite experience with MT-90. My Audi shifts much smoother and less notchy with MT-90 compared to the OEM fill.
moribundman - Like someone posted, every trans seems to prefer some fluids over others.
But in your case, I wonder if changing the original, particulate laden, possibly sheared, fluid, with any other suitable fluid, would also have produced better shifting?
But in your case, I wonder if changing the original, particulate laden, possibly sheared, fluid, with any other suitable fluid, would also have produced better shifting?
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The transmission fluid was 60k miles old when I changed it. Unlike the rear differential fluid, it came out looking clean without visible metal flakes. If I remember correctly, the transmission, even when the car was new, did not shift as smoothly as it does now with MT-90. Of course, maybe my memory is tricking me.
MolaKule
Staff member
Have you read other threads where a 50/50 mix of MT90 and MTL solved both cold shifting and notchiness problems?
In manual transmissions requiring GL4 ratings, there are three main criteria for all weather shifting and detent.
1. Correct viscosity of oil
2. proper friction-modification additives.
e. Proper level of Extreme Pressure additives.
The only difference between MT90 and MTL are the viscosities and friction-modification. The EP additives are the same GL4 set for both.
MolaKule,
How does a car/transmission manufacturer decide what viscosity to use in a particular transmission?
I remember the white paper you had posted a while back, “A White Paper on Using the Lasche and McKee Equations to Determine Lubricant Viscosity“. Does this apply to non-journal bearings as well?
Will using ATF vs 75W80 vs 75W90 make any significant difference in bearing/gear longevity? Or is the viscosity recommendation solely based on ease of shifting?
How does a car/transmission manufacturer decide what viscosity to use in a particular transmission?
I remember the white paper you had posted a while back, “A White Paper on Using the Lasche and McKee Equations to Determine Lubricant Viscosity“. Does this apply to non-journal bearings as well?
Will using ATF vs 75W80 vs 75W90 make any significant difference in bearing/gear longevity? Or is the viscosity recommendation solely based on ease of shifting?
MolaKule
Staff member
The manufacturer decides to use a certain type of fluid based on:
1. Torque/horsepower
2. type of gearing
3. material types
4. clearances
5. type of synchronizers
The Lashee-McKee thing is not used for transmissions.
It is my view that ATF is primarily specified for cold shifting requirements and not for longevity, since the AW/EP add pack's in ATF are weak compared to GL4-5 gear lubes. To prove this to yourself, go to the VOA section and search on ATF and Redline MT fluids. You will see that the MT fluids have 8-10 times more EP/AW adds than do ATF's.
In transmissions with needle bearings, a light GL4 or SynchroMesh rated lube is often specified, since it offers better AW/EP protection than does ATF.
Well Ive been using this MT-90 for a couple of weeks now. After I got over the initial "excessive shifting" to test out the new fluid, I really dont notice it anymore. Im sure its good stuff, and it better be because I drive the snot out of this car and it keeps taking it. Made it 76K on the factory fill. I dont think you ever need to change manual gear oil really. But it cant hurt once every 50K.
A) I agree w/ your comments on synchromesh - In fact I'm confused as to how they can be directly compared to GL4s. In many cases I thought transmissions were specifically designed for synchromesh and therefore don't run a traditioanl GL4 - or vice versa.
B) I don't agree about every oil company offering GL4s for several reasons. Most major nat'l brands do not. In fact you only listed one major national brand up there - the rest being limited availability, specialty, perhaps even boutique brands. THe QState, while it is a national brand, is only available if you happen to live in a metropolitan area w/ an oil distributor that can special order it for you but of course one must purchase an entire case and pay something in the range of $22 PER BOTTLE! In my opinion one must scrounge, mail order etc to even have a modicum of GL4 selection. Also I think it's worth distinguishing between pure GL4s and those that are GL5s that happen to also meet the GL4 yellow metal requirement. The reason I say this is the EP additives, beyond (potential) affect on yellow metals (A GL4 rating should negate this), may also impact 'shiftability' as some synchros tend to be sensitive to a lube that is too slippery.
C) I also agree w/ yoru point about smooth shifting and confusion - I've watched these forums for a long time and there simply is no consensus as to these perceived terms. For that matter I increasingly certain that there are differences as to which brand works best in which transmission for which owner - E.g. it quickly grows to a more complex 3 variable function! (owner shifting preference, transmission make, lube brand)
thanks,
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