How does GM synchro mesh transmission fluid solve 3rd gear issue? Can someone explain in detail? (no semi-educated guess please)

 

There has not been a single post that clearly states what causes the tranny to not fully engage 3rd gear. There is a lot of speculation but no one knows for sure, at least no one has stated it on this forum. With the acknowledgement that no one knows exactly what is wrong no one will be able to state with any authority what GMFM fluid actually fixes. Everyone knows it fixes the problem but no one knows why.

 

Semi educated opinon coming up

I take it the design on the 3rd gear synchro and stock fluid and possibly clutch engagement point makes it possibly to grind 3rd gear which rarely is my problem never had it pop out on me which has a bunch of other possibilities. I'll only grind when its really cold and even then im thinking its because I don't fully depress the clutch.

Just switched out my GM Synchro FM fluid for some Amsoil Synthetic Synchromesh 5-30 and it feels pretty good, a little slicker probably closer to Penzoil Synchromesh viscosity since the FM version feels thicker to me. Well i'm looking foward to testing out the fluid in colder temps lets say when I start it in the morning and take off andshft into 3rd for the first time.

 

That's exactly what I was thinking when I first saw 6spdtls post. Nobody I know of has actually done any science on this with actual parts and testing equipment.

I use the GM stuff but here is a Redline Oil publication that I found interesting and informative. (link ). Read the section called "BENEFIT SUMMARY" (which is most of the first page) and it may open your eyes to some of the various things that could be affected by MTF formulation. To me it almost as if they wrote it about the TL's 3rd gear.

I'm not an expert but I really think it's simply a case of the friction and viscosity attributes of the GM fluid just happening to be more suited to the synchros in the TL. Not saying the TL's design is bad, the GM fluid is superior or anything like that. I'm just saying I think it's synchros and thankfully the GM stuff is around.

6spdtls - I know you said no "semi-educated" guesses, it's not, it's a wild ass guess (WAG)

 

I was having issues with my 3rd gear and what the dealer first did was change the trans fluid, but after a couple of weeks the issues were coming back. After that, the dealer changed the synchro for the 3rd gear.

Well, after the change, my 1st gear was having the same issues and some times it would happen with the 4th. The tech told me at cold temps it can do that, and generally that's when it happens. I asked if it just needs to be "warn in", but never really gave me an response....

So, what I'm going to do is wait a little and see if there is any improvement, if not I'll have them replace the whole trans -- this would be the 3rd time I had to get this fixed. Anyone know about the "lemon law"??

 

I reported the same problem with my manual 07 type-S. I called the regional case manager, awaiting an answer about it..

 

I also have the third gear notchy shifting issue. Acura replaced the fluid today, and on the drive home it felt a lot better. Part number 3 08798-9031A Fluid.

Will post again in a few hundred miles to see if the problem remains solved.

 

no need to lemon law. just put in gm synchromesh and your problem will go away. 100 new transmissions will not fix your problem. i replaced my fluid with gm syncromesh like many others and have been problem free.

 

I doubt the GMFM fluid will fix the problem since the dealer already messed it up worse than it was. It is time for a new tranny. My second tranny is problem free with the Acura fluid. This is a very common problem but it is not on the majority of cars. Anyone that replaces the tranny stands a very good chance that they will not have the problem again.

 

I suggest to go over all major 3rd gear problem threads and check out the RR journal in the 3G Garage and on S2K on tranny oil. It gets technical with the 3rd gear syncro but the RR guy did an analysis and comparison on the GM juice and it proved a better quality oil than the old water thin Honda stuff. No wonder that oil doesn't provide adequate lube in the long term. Their oil is only part of the problem though...

In other news, the new reformulated Honda oil is a marked improvement. The 3rd gear goes in much smoother, no popping so far. I'll see how it holds up over time though, fingers crossed, I'll keep the interested posted.

 

Remember, you need to get the "Friction Modified" fluid:

Part #12377916 -GM SyncroMesh Manual Transmission Fluid- Friction Modified.

I use it in mine, and I, along with every single person who I've come across that uses it, swears by it. No, we don't know why it works, but thank goodness that it does work!

 

so this begs the question, Redline MTL or GMSMFM, Nice article Adobeman, very imformative!

 

I just got my 07 TLS back from service. They told me my transmission fluid was "contaminated" and that is what caused the 3rd gear problem. I guess they replaced all of this fluid. Does this make sense?

 

No, it does not. Did the new fluid help?

 

Need to test more, not sure.

 

I'm going to install some GM shizit in my tranny in about a week, i'm looking forward to the results.