Is my MT bearing failure oil-related ?

[circle1m]

One year with Motul Gear 300 in my MT (1993 Nissan D21 Hardbody). I switched because cold weather shifting was pretty miserable. A year and ~20,000 miles later, I have a noisy bearing. Shifting great, but a noisy bearing. I will be having the necessary repairs made soon and need to decide what to use. The Motul is GL-4, GL-5. The recommendation for my MT is GL-4.

To be fair, the truck has 321,000 miles on it and I had a bearing go south probably around the 150,000 mile mark, +\- 25K. Don't remember exactly.

The conundrum: The Motul absolutely cleared up the knotchy (and beyond knotchy) cold shifting issue. I have been loving it.

However, I'm now questioning if the GL-4/5 Motul contributed to the bearing going down. I want to think that if this was oil-related with soft metal damage I would have shifting issues, which I do not. I am far from a mechanic and I simply don't know the answer to this question, so I give it to you guys.

If the recommendations lead me to choosing a strictly GL-4, I am leaning toward Amsoil because it had the lowest temperature pour point (not as low as the Motul, but the lowest of the GL-4s) that I could find. My issue was primary a cold weather issue. Does that make sense with regards to pour point, or do I misunderstand what that means ?
Thank you.

 

[aquariuscsm]

I hear of people using the Motul stuff in Z32's with excellent results. What are your noisy bearing symptoms? What fluid were you using before the Motul? Go with MT90 if you decide to switch it out.

 

[circle1m]

Symptom- whining noise in every gear except 4th (and maybe reverse). Prior to Motul, which was my decision, I believe my mechanic used and standard GL-4 (unsure if it was syn or non-syn). He used Lucas additive, I think, because I told him that I would like to clear up the cold shifting issues. I had no failures, but it didn't do much for the cold shifting, thus the move to Motul.

 

[zeng]

What's the viscosity grade in it prior to Motul Gear ? and factory's recommended ?

 

[gman2304]

I had a similar problem with my 1995 Nissan D21 5 speed MT. I changed the factory fill at 50,000 miles and used Mobil1 75w90. At 150,000 miles, I changed it to the Amsoil. I can't remember if I used gl4 or gl5 but I remember researching it and I used the type that was recommended. At the 170,000 mile mark, 3rd gear started making a whining noise. I sold it at 175,000 miles but have wondered if I had left the Mobil1 in it if it would have been OK, or the Amsoil had something to do with the bearing failure. I have since read the 5 speeds were the weak link in an otherwise bullet proof little truck. Not trashing Amsoil, but that was my experience. IDK.

 

[Kestas]

There are many reasons a roller bearing can fail besides lubrication.

I'm not sure about 1993, but lately I've been finding out that automotive gear cases (transmission, transfer, and differentials) are very dirty environments for roller bearings, relatively speaking. Compounding this fact is that manufacturers are shaving off any robustness with the bearing. They are operating on the fine edge of perfection.

I've been finding bearings in automotive gear box operation often suffer from debris denting, which develops into surface spalling. I've been trying to convince manufacturers to incorporate a fluid exchange at the consumer level after the units are broken in to remove break-in debris, but I don't think that will ever happen. Instead, they want bearing manufacturers to pull a magic rabbit out of their hat and make a bearing that is resistant to debris denting ($$). They want their fill-for-life.

 

[Kuato]

+1 on Kestas' comment about shaving robustness. You did say a bearing failed at 150k. If it's the same bearing this time then it is a weakness in the transmission, and not the lube's fault. (and I highly doubt that the Motul would have caused the failure anyway)

That said, I drove a 70s Chrysler product manual transmission that had a whine in it. Replaced the bearing, within maybe 15-20k it was whining again and never had an issue for another 150k miles...and it whined the whole time.

 

[Greasymechtech]

http://www.nissanpathfinders.net/files/NTB97-009a - FS5R30A TRANSMISSION WHINE.pdf

Incorrect fluid capacity caused by incorrect fill plug location.

 

[MolaKule]

Quote:
However, I'm now questioning if the GL-4/5 Motul contributed to the bearing going down. I want to think that if this was oil-related with soft metal damage I would have shifting issues, which I do not.


+2 on what Kestas stated.

I seriously doubt there is any connection between a steel bearing failure, the brass synchronizers, and the fluid you're using.

Bearing failures in MT's are not uncommon no matter what fluid is used.

 

[Chris142]

A roller bearing does not need much lube. I'm guessing any reasonable lube would be fine for the bearings.

I think it just wore out

 

[Kestas]

Manufacturers are presently going toward thinner oils in their quest for better efficiency and CAFE numbers. This works against the bearing's resistance to heavy stress loads and debris denting.

I can't recommend using thicker oils without knowing how it would affect other aspects of the unit's function.

 

[MolaKule]

Originally Posted By: Chris142
A roller bearing does not need much lube. I'm guessing any reasonable lube would be fine for the bearings.

I think it just wore out


No way, it only has 341k on it.

 

[aquariuscsm]

GL5 is definitely a no-no in your Nissan's transmission (because of the yellow metal synchros) . I bet it's the same transmission that's in my 300ZX. Drain and refill it with MT90 and see what happens. I'm 99.9% sure the Motul has nothing to do with your tranny whine,but the MT90 will be good for the synchros.

 

[DoubleWasp]

Originally Posted By: Kestas
Manufacturers are presently going toward thinner oils in their quest for better efficiency and CAFE numbers. This works against the bearing's resistance to heavy stress loads and debris denting.

I can't recommend using thicker oils without knowing how it would affect other aspects of the unit's function.


That's why I use the Mercedes gear oil in my Ram (Mercedes G56 trans), instead of the ATF+4 Mopar uses. You're not going to catch Mercedes using ATF in this trans, but Chrysler decided it knew better than the people who made it.

 

[Greasymechtech]

Originally Posted By: circle1m
Symptom- whining noise in every gear except 4th (and maybe reverse).


If an R30A transmission exhibits a whine noise while driving in all forward gears except 4th
which is more pronounced at slow speeds, the incident may be caused by lack of
lubrication to the main and counter drive gears. This noise may occur particularly on
acceleration and/or climbing hills.
A countermeasure transmission case is available to resolve this incident.

The transmission oil level has been increased from 3.6 to 5.1 L (an
increase of 1.5 L) to prevent lack of lubrication. The oil filler plug has been relocated to compensate for the oil level increase

If your transmission is the one that the TSB mentions and doesn't have 5 quarts in it, it will simply self destruct again and again.

 

[DoubleWasp]

LOL. Now that really sounds like the G56.

Time to do what we do: Overfill it by 1.5 quarts through the shift tower.

BTW, very few GL5's are left that are not compatible with yellow metals. Technology has caught up to this issue.

Make sure to use a lube with robust anti-foam properties. Never a proven theory in overfilling applications, but there's a possibility that the overfilling can make the trans more prone to foaming.

 

[zeng]

Originally Posted By: DoubleWasp
BTW, very few GL5's are left that are not compatible with yellow metals. Technology has caught up to this issue.


+1

Additives in most current day GL5's, among others with metal deactivators technology ,has long caught up with yellow metal compatibility issues in differentials/transfer cases/manual transmissions.

Just check to ensure it has a PDS/TDS displaying ASTM D130 Copper Corrosion Test ratings of 1A or 1B , not 3A rating in yesteryears.

It would be comforting to see , and I personally would not be concerned though,the product has approvals of SAE J2360 or MIL 2105E. Neither do I worry about manufacturers abstention from claims of GL4 compliance in its GL5 products.

JMHO.

 

[aquariuscsm]

But do the modern GL5's contain the LS ads that was always said to wreak havoc with the synchros,causing shiftability issues? I tried a double rated GL4/5 one time and it would grind going into every gear. Drained and refilled with spec'd GL4 and it shifted like brand new again.

 

[zeng]

Originally Posted By: Kuato
That said, I drove a 70s Chrysler product manual transmission that had a whine in it. Replaced the bearing, within maybe 15-20k it was whining again and never had an issue for another 150k miles...and it whined the whole time.


Whining noise from a typical transmission/differential/transfer case originates from worn gear profiles.

It could be further exacerbated by worn bearing rollers , and rarely a worn bearing housing.

Your attempt at replacing worn bearings would certainly help , to a certain extent.

Unfortunately it's inadequate in this instance.

Just my $0.02.

Note: A worn bearing by itself would not produce a 'whining' noise that we typically associate with a gearing system. It gave a different 'tone' of noise, if you know what I meant.

 

[Rendezvous]

Originally Posted By: DoubleWasp
Originally Posted By: Kestas
Manufacturers are presently going toward thinner oils in their quest for better efficiency and CAFE numbers. This works against the bearing's resistance to heavy stress loads and debris denting.

I can't recommend using thicker oils without knowing how it would affect other aspects of the unit's function.


That's why I use the Mercedes gear oil in my Ram (Mercedes G56 trans), instead of the ATF+4 Mopar uses. You're not going to catch Mercedes using ATF in this trans, but Chrysler decided it knew better than the people who made it.


Which Mercedes gear oil are you using?