Synchromesh fluids and GL-# ratings....

[MolaKule]

Supposedly, Yes.

For example, Motul Gear 300 and similar fluids are GL-4/5 rated synchromesh fluids, but that rating is because these fluids are used in a common sump, where a synchromesh transmission and a hypoid differential share the lubricant.

Subaru MT drive train systems are typical configurations.

Motul Gear Oil

 

[gregoron]

Molakule, how about adding Valvoline MTF Synchromesh in your list? I know we still don't have the PDS on it in a separate thread.

 

[MolaKule]

As soon as we can verify the application(s) and viscosities we will do that.

The problem currently is this: the data initially supplied by antiqueshell implies synchromesh applications for 10.x cSt (5W30) fluids similar to the GM and Chrysler Synchromeshes.

The one I found implies a (75W90) synchromesh with applications directed toward Toyota and VW applications and others that use a 14.5 cSt synchromesh fluid.

 

[Sequoiasoon]

Molakule,
Maybe I missed it. Where does Pentosin MTF2 fall in the list?

I'm doing the reading based on the KIA tranny thread. My '07 Sonata (5 speed manual) was horrible when cold trying to shift 1-2 and OK when warm even when it was brand new. Colder temps of course made it worse. After 1 year I switched to BG Synchroshift II to try (because it made a huge difference in my Corolla that spec'd same fluid). Shifting on the Sonata was better but still not great. Some others with same tranny had done their own 50/50 Redline MTL/MT90 mix basically making a 75W85 and said it was better than the stock fluid.

Redline has the MT85 which is on your list and matches factory spec. I just put that in the Sonata and so far I'm not thrilled (as compared to the BG). Tougher shifts when car is cold (and it's warm here in NY can't picture once winter comes) and when tranny is warm the 1-2 shift is not consistent. Sometimes smooth, sometimes notchy, sometimes almost feels like slight grind. Other gears feel a little tougher than they used to.

I'm tempted to try the Pentosin MTF2 (also seeing the TSB for the Genesis) and some where here at BITOG read the Pentosin PLUS M02S gear additive (or was it Synchromesh and M02S) recommendation but that was in a VW iirc.

I know when the shop changed the fluid for me they just did a drain and fill. Reading the Genesis TSB they say drain/fill run for a couple minutes in 5th gear or drive 1/2 mile and repeat drain/fill. I'd hate 2 waste 2 qts of any of the fluids. How much is really left that the new fluid mixes with if you don't do the second D/F. Tranny only holds 2qts.

So far the MT85 has about 1000k on it. The BG was noticeable (in a good way) after about 50 miles in the Sonata and my old Corolla. The MT85 i;m not sure when I started noticing teh tougher shifts but definitely the last 300 miles its been annoying me.

 

[MolaKule]

You may have to try the lower viscosity sychromesh's to determine which works best.

Redline MT85 is a 12 cSt MTF.


Quote:
Molakule,
Maybe I missed it. Where does Pentosin MTF2 fall in the list?



The Pentosin MTF 2 is a 7.7 cSt MTF. I am in the process of updating the list.

The BG Synchroshift II is an 8.2 cSt MTF.


Quote:
B. The next higher viscosity MTL would be the 7.5 cSt versions (About the same viscosity as a DexronIII)

1. Royal Purple's Synchromax

2. Ravenol MTF-2

3. Honda MTF

4. VW part number G052512A2

5. GM Manual Transmission and Transfer Case Fluid

6. BMW (Pentosin MTF 2) MTF-LT-1, 2


C. The next higher viscosity MTL would be Castrol Syntrans V FE 75W-80 8.0cSt

D. The next higher viscosity MTL would be BG Synchroshift II 8.2 cSt

E. The next higher viscosity is Mopar Type MS-9417 MTL 9.0cSt

F. The next higher viscosity MTL would be Pennzoil Synchromesh 9.3 cSt

 

[MolaKule]

Did you check with Helen (site Owner) or any of the mods such as Wayne Wilson to see if this is allowed?

 

[dwgwater]

My 1970 MG midget specs SAE 30 motor oil for the trans (non-synchro, straight cut first gear, synchros on the other 3), and for many years people have been using 20W-50, which I'd guess shears down to 30 weight pretty quickly. Would one of these MTFs be suitable to substitute for motor oil in a transmission, as opposed to the gear oils discussed so far? It might be nice to have a modern friction modified synthetic lube leaking onto the garage floor for a change

 

[MolaKule]

For 30 weight applications of approx. 10.0 cSt, any of the fluids listed below will provide better anti-wear protection than would any engine oils, especially Group G.:

Quote:



E. The next higher viscosity is Mopar Type MS-9417 MTL 9.0cSt

F. The next higher viscosity MTL would be Pennzoil Synchromesh 9.3 cSt


G. The next group of MTL’s are in the 10.x cSt range are:

1. Redline MTL 70W80.

2. Amsoil MTL

3. GM Synchromeshs’

4. Volvo MTF 645

5. Ford Motor Craft XT-M5-QS

 

[dwgwater]

Thank you MolaCule. Can I follow up up about viscosity in a gearbox without hijacking the thread? In my gearbox (and in most, I assume) the lubricant isn't being pumped, so the resistance to flow aspect of viscosity isn't comparable that in to an engine. I envision the gears/shafts essentially spinning in a bath of oil. If I use a lower viscosity lube, like the Pennz. Synchromesh (cSt 9.3) (which is relatively cheap and available) vs. one of the higher viscosity MTFs, what am I losing or gaining, if anything? Perhaps a thinner film, but is that offset by the superior characteristics of the EP/AW compounds of the GL4 vs. motor oil? What role does viscosity play in gearbox oil?

 

[MolaKule]

Quote:
What role does viscosity play in gearbox oil?



What vehicle and year?

Try this reference and see if answers your questions.

Technology of MTs and MTLs

 

[SHOZ]

I've got a 2010 Hyundai Genesis Coupe with the 6 sp manual transmission. It's a horrible trans and is hard to shift into rev and 1st, and has a 5th gear grind when warm.

Currently I have Redline lightweight shockproof in it. Hyundai originally called for 75w90 and then revised it to 75w85. They have even tried an ATF type fluid. No really help.

But they specifically say (now) that the Shockproof/MTL type fluids should not be used.

Any insights in what would be a good fluid to use?

 

[MolaKule]

Quote:
But they specifically say (now) that the Shockproof/MTL type fluids should not be used.



Schockproof and MTL fluids are not the same type of fluids nor in the same league. The shockproof oils are differential fluids.

Is there a TSB out on this problem?

Some transmission designs are just, well, crummy.

I would try a lower viscosity (thinner) dedicated MTL such as:

Redline MTL70W80, Amsoil MTL, Pennzoil SYnchromesh, or any of the GM Synchromesh's.

Let us know how any of these work out.

 

[SHOZ]

The only TSB is to change from the original 75w85 to 75w90.

Quote:
DESCRIPTION:

This bulletin provides the availability of genuine Hyundai 75W/90 (API GL-4) manual transaxle oil through the Hyundai Motor America parts distribution system.

All Hyundai manual transaxles produced beginning July, 1998 (1999 MY) have been filled at the factory with 75W/90 (API GL-4) oil.
NOTE
Hyundai vehicles produced prior to July, 1998 were filled with 75W/85 (API GL-4) manual transaxle oil.
75W/90 (API GL-4) manual transaxle oil can also be used in all Hyundai vehicles produced prior to July, 1998.

The characteristics and benefits of the 75W/90 (API GL-4) oil are:
Improved low temperature viscosity
Excellent shear stability
Excellent oxidation stability (long term lubrication characteristics)
Improved load capacity
Improved long term shifting performance
PART INFORMATION:
PART NAME PART NUMBER SPECIFICATION QUANTITY
Manual transaxle oil
08950-00010-A
75W/90 (API GL-4)
[SAE 75W/90 (TGO-6)]
As specified in the Owner's Manual (see Vehicle Specifications) of applicable model




Seems the Redline MT85 is the best but still does not fix the problems. Some are using a Mitsubishi Diaqueen 75w85 3717610 oil to but it's only been a month.

 

[MolaKule]

Some MT trannies are simply finnicky, and you cannot fix a worn tranny or a bad design with a simple fluid fix.

Try the MTL70W80 or any of those I listed to see if shifts better with a lower viscosity fluid.

The Redline MTL70W80 has more than an ample anti-wear additive pack so you won't be risking wear while testing it.

 

[SHOZ]

Thanks, I'll order some. It appears to be an assembly problem. It's made by Hyundai and they know what the problem is. They just keep warrantying them out. Some are on their third trans.

 

[gregoron]

My 2k Jetta manual tranny has issues downshifting to first gear as seen in multiple VW threads. I had in it the G60 OEM MTF which was thinner than the original G50 specified for it in 2000. It exhibited notchy and no shifting at 1st gear. Since I replaced it with the thicker and original application spec Redline MT90 75W90, the notchiness has diminished significantly. I don't have non-shifting issues anymore.

 

[MolaKule]

When I produced my own fluids, I never recommended anything lower in viscosity than my 75W90 MTL-R for VW's.

But my inference above was to try the lover viscosity oil first for about 1000 miles, and if the performance doesn't improve, then go up a notch (no pun intended) to say MT85 (12.0 CsT), and then if that doesn't do it, go up to a 14 cSt (75W90).

In many cases, the manf. of smaller HP vehicles usually over-specifies the viscosity for their MT's as a CYA spec. and to cover their crummy transission designs.

I can't tell you how many racing tranny manf. have come to me after the design and testing to ask me to build them a fluid to cover their mistakes.

I work with them but also point to the fact that if they had included a lubrication engineer early in the design phase, development would have been lest costly.