Having followed recent gear oil post

[NWMO]

Good afternoon all,

The Rusty Frog had set for an undetermined length of time before I aquired it and recently started using it as my daily driver. It currently shifts fantastic up and down, but I know I need to change the gear oil. Here is the product I have purchased, any concerns?



Chris

[Jonymoto]

I use 75W-90 oil myself, but there seems to be a concern about using GL5 oil in the Tercel gearbox. Apparently they erode the brass synchros. I've been using GL5 for years and I haven't had any issues. Maybe the others with more experience with our gearboxes like Petros or Xirdneh might like to comment on this point.

[Gottolovem]

Oh boy here we go lots of opinions here about what oil to run in the gearbox.
I think what you have there will due fine (others will not) perhaps one quart of good synthetic in the mix is a good idea.

[xirdneh]

Pretty sure FSM says GL 4 or 5 is OK
I would look but am not near home

[Jonymoto]

The FSM says API GL4 or GL5. However check the post below:-
viewtopic.php?f=2&t=9667&start=30#p89436

[dlb]

haha, agreed with gottolovem. you'll get tons of different opinions on this but here's mine: if the manuals all say GL 4 or 5, i think they're fine. trans gears naturally wear over time so it's not surprising that most of these transmissions have worn synchros -- i think if GL 5 stuff was going to destroy the brass parts, there would be no working tercel transmissions at this point since that's what they probably came with and what most of us have continued to put in them for the 30+ years they've been around.

[Jonymoto]

I agree with you too dlb. I've been using GL5 for the last 32 years with no issues as I wasn't aware of the brass synchros issue till a week ago. So I'm glad you guys are not concerned about it and probably using it too.

[The Professor]

I would hesitate to use any oil rated for "Limited Slip". This means it has extra friction modifiers that will increase wear on your syncros.

[NWMO]

Hey All,

After nerding out some this morning I am providing the following links for those interested:

heady stuff

Redline MT (pic 3) "not for use in most manual transmission with sycronizers, as it's slipperiness may cause gear clash"

If it shifts ok, it sounds like the protection is ok


possibly my choice

I don't want to provide MY synopsis as it may influence others before reading.

Chris

[NWMO]

Good Morning,

With a lack of responses at this point, I will provide a VERY brief synopsis (as I interpret the attached article).

GL-5 gear oils will likely provide better protection for the differential gears, however, it appears they also INCREASE wear on the synchros (not because they "attack" anything, but because the viscosity characteristics cause it to grip the synchro better and thus remove additional "brass" material as the oil is stripped away.

GL-4 gear oils will likely provide less protection for the differential gears, however, they apparently decrease wear on the synchros as they do not grip the brass as enthusiastically and thus when the bond is broken, less brass is removed.

So, depending on which components likely have a better "service life" and/or are easier to find/replace, a decision could go either way.

I would ASSUME the synchros are more challenging to find and replace, thus I would likely select the GL-4. However, if they are sufficiently "over built" in the first place such that they almost never wear out (as reported), it may be better to go GL-5 and provide more protection to the differential gears? Then again, I would expect with the light weight of the Tercel and the limited power of the 1.5L engine, the differential gears are probably "over built" and less likely to be a failure point than the transmission and thus select GL-4 gear oil.

Does this remind anyone else of the "poisoned drink" sequence in The Princess Bride ?

Either way, I will NOT be using the pictured gear oil above. All comments appreciated.

Chris

[dlb]

Does this remind anyone else of the "poisoned drink" sequence in The Princess Bride ?

yes! great scene, great flick. funny because i was actually just thinking about that scene the other day.

[ARCHINSTL]

Does this remind anyone else of the "poisoned drink" sequence in The Princess Bride ?

yes! great scene, great flick. funny because i was actually just thinking about that scene the other day.

For those who may have forgotten: https://www.youtube.com/watch?v=U_eZmEiyTo0
Tom M.

[Ridlbox]

That's one of the greatest comedic films ever written great post to buy myself will be going with the less abrasive

[NWMO]

That's one of the greatest comedic films ever written great post to buy myself will be going with the less abrasive

Thanks Tom & Ridlbox,

Tom - thanks for the video, I truly enjoy that movie. Better yet, it's on Netflix, guess what I'm watching this weekend! Of course, I'll have to wait for my better half to be busy or go to bed, I don't know that I have ever met a woman that cares for that movie

Ridlbox - Thanks for the input as I do feel a bit like Vizzini. I expect the transmission synchros are harder to come by and will be using the GL-4.

Chris

[Petros]

both my daughter's liked that movie. The whole movie is so odd I think it has taken on cult status and has become an underground classic.