Transmission fluid recommendation. Redline, mobile 1, Toyota? (1 Viewer)

[esoniat]

Fj60 with stock 4 speed manual transmission. I bought it new and for as long as I can remember I've been running redline synthetic fluid. I forgot to spec it last time and got mobile 1 synthetic this time.

Before the shifts were unnoticeable, super smooth and easy. Now not so much.

Is this all in my head?
Recommendations?

 

[WarDamnEagle]

Redline MT90

 

[OSS]

Mobile 1 75w-90 gear lube is specifically recommended to NOT be used in transmissions.
Decades ago it was the cat’s meow of synthetic gear lubes but they’ve found (and I found) it doesn’t play nice with the synchros. The oil is too slippery so the synchronizers can’t grab the gears to slow them down - so the shifting gets un-smooth.

Use redline MT-90 if you want a 75w-90 oil or use Mobile’s Delvac Synthetic Transmission Fluid 50 if you want a straight (synthetic) GL4 gear lube (my favorite).

Even the regular ole Sta-Lube 80w-90 is fine.

 

[dbbowen]

The Redline MT90 is pretty well known for smoothening out shifting in old transmissions with brass syncros. You were pretty much using the best stuff you could from the get go.

 

[esoniat]

Thanks for the feed back. I'm might be crazy but the transmission shifting doesn't prove it.
I'll dump the Mobile 1 ASAP and go back to Redline.

 

[SteveH]

You can also run a custom blend. In my '98 4Runner, I ran 2 qts. conventional and 1 quart synthetic. Now that it's older and tired-er, it I run full synthetic and it shifts well. It seems many people's experiences vary, depending on how they shift. In your case, I would start (as you indicated you would) with Redline and go from there.

 

[brian]

Anything gl4 rated is just fine.
These trans and transfers are not picky enough to care about anything other than the rating.

 

[John McVicker]

I’ve ALWAYS used Walmart brand gear oil. Not at all saying that’s the best…just what I have used. These are not Maserati’s we’re driving.

Bought my ‘75 40 new, still a shared daily driver. Have had my 60 for 19 years now…400k miles. No issues using this stuff.

 

[scottcb]

So I’m going to bring my 06 Corolla into this conversation to help support the pro-redline theory. Bought the thing with 150k for my kids to drive. They are out of the country right now so I’ve been driving it. Since acquiring the car, we have done all the maintenance on it. But as I’ve been driving it, I started wondering about the transmission oil and realized or figured it had never been changed. So I got the bright idea to change it and put mobile one synthetic in. That was a huge mistake! Prior the car shifted pretty much just fine, a little clunky from 2nd to 3rd or fourth the third. But for a car that old I didn’t have any concerns. As soon as I changed it to the mobile one, every time I shifted from third down to second, I was grinding like crazy. I figured it was the oil and called the local transmission shop, and he told me to switch to the cheapest convention gear oil I could find that met the original specs. I did that, and the shifting improved with less grinding, but when the transmission got extra warm from extended use, it would grind a little bit again. so after reading all the reviews about the red line transmission oil, I drained it a third time and replaced it with the red line. I have not had any issues since and the transmission is now shifting better than it ever has. So my conclusion is if there is extended wear in your old transmission, the red line stuff is a good way to go. Now I do have an 85 fj60 and I changed the transmission oil out about three years ago. Don’t drive it a whole lot but shifting down to third has always been a little rough. I usually just engage the gear extra slow or skip it all together. So I am going to, try the red line in the Land Cruiser and see if it improves that issue.

 

[OSS]

and put mobile one synthetic in.

I used to use that oil - and yes it’s too slippery. Synchronizers can’t get a grip. Mobil doesn’t recommend it for transmissions anymore.

 

[Spook50]

I used to use that oil - and yes it’s too slippery. Synchronizers can’t get a grip. Mobil doesn’t recommend it for transmissions anymore.

I've become a die hard AMSOIL fan lately. A few weeks ago put their 75-90 "manual transmission fluid" in my H55F and it feels noticeably smoother at highway speeds than Redline or Royal Purple did. Also made the notchiness shifting into 3rd (worn synchro ring I'm certain) barely noticable when before I had to be careful shifting or it would catch and give me hell shifting. No other oils I tried were able to do that so I'm definitely sold on it.