Manual transmission fluid

I just purchased this truck from the original owner. It has 167 k miles but none of the fluids have ever been changed. The clutch and tranny seem okay still. Both are stock. However, I've been noticing in the mornings it's a little rough to upshift until it warms up. I want to replace all the fluids. Any recommendations on a preferable brand? The manual calls for 75W-90. Thanks

 

I mean, if it was me, and I wanted to go with non-synthetic, I'd go with Lucas 80w90 for your MT. If I wanted synthetic, I think Valvoline has their 'Daily Care' or whatever 75w90 that's designed for the 4spd MT.

 

I always liked Red Line MT 90 in my Tacoma with a manual tranny. But there are plenty of good fluids out there...

 

Are Tundra synchros made of brass? I’ve been told newer GL-5 oils contain sulfur and are corrosive to brass and that a GL-4 oil is a better choice. It will soon be moot as manuals are getting so rare as to be deemed millennial anti theft devices. Maybe an engineer on this forum has some insight?

 

I can't imagine the 2001 Tundra manual transmission was much different than my 1998 Tacoma. I definitely used GL4, which is what the Red Line MT90 is.

 

Second on the Redline MT90. Really really good stuff.

I run Redline oils in my Fiat and it made the transmission shift significantly smoother and killed a lot of the differential whine. I also put their Shockproof Superlight in my old Honda Insight when it had similar symptoms to yours. Worked like a charm.

 

I'm just going to assume you mean none of the fluids except engine oil.

 

That's correct. Yes he was very anal with that but never believed in changing any of the fluids. Lol

 

I'm not sure if there's an advantage to going synthetic or not?

 

Regarding the Redline MT90, should that only get used for the MT? Reason I ask is because it looks like the transfer case and MT both take the same GL-4 or GL-5 75W-90 gear oil. The front diff takes a GL-5 75W-90 hypoid gear oil and the rear diff takes a GL-5 SAE 90 hypoid gear oil. If I'm changing all of them out, can any of the same fluids be used more than once or so I need all different fluids?

 

So you use the Shockproof Super light in one of your MT's instead of the MT90 or mixed together?

 

I'd be hesitant to run the MT90 in the differentials or transfer case. I believe it is specifically designed for use in a manual transmission, not in a transfer case or differential. It's a GL4 so it will not harm brass synchros.

I personally run Valvoline gear oil in my transfer case and differentials, and I think that most of the gear oils you could buy at a parts store would suffice. Unless you are towing or hauling very frequently, I don't think it's critical to run super fancy oils in the diffs and transfer case. When I changed mine after 100k miles they were all surprisingly clean. Redline oils, while being very good, are also very expensive.

I used Shockproof Superlight in the transmission in my Honda, as it called for a very light weight oil. For your transmission, I'd recommend MT90. It's a 75W-90 (not sure why it isn't called MT75-90) that's meant specifically for manual transmissions.

 

Thank you!

 

It's annoying to buy multiple fluids, but probably safer. I don't know enough to know, which is why I use what they call for. Transmission calls for GL4, other gearboxes GL5.

Benefit to synthetic? If you believe the hype. Many of us do. The transmission on my 98 had a whine when I bought it, at around 190,000 miles. I don't know what my friend (first two owners were friends) used, but I started using Red Line. Whine stuck around for years but never got worse, and eventually went away. I sold the truck at 330,000, original transmission.

I don't think Red Line or any other synthetic fluid are a magic cure-all, but I think good fluid and regular changes can head off some problems if you catch them early enough, and there seems to be some benefit to using a synthetic on gearboxes that were abused/neglected.

 

Thanks for the info! I use synthetic engine oil in all my vehicles too and they run great with over 250k miles on each. I ordered the MT-90 for the tranny. How often did you change out the tranny fluid on that 98 truck? I'm assuming that was a MT too?

 

Yeah, it was a manual. I didn't stick to any strict oil change protocol other than once a year. I towed with it, so it saw heavier duty use. T-case and front diff were another thing, but I'd try to get the rear diff and transmission once a year, in the fall after I was done towing the camper for the year. I think 20-30,000 miles is a good ballpark interval though for most people.

 

I changed out all the fluids and used the MT-90 for the tranny and it is noticeably smoother now; especially when cold. Thanks for advice! I guess 23 year old fluids finally needed to get replaced!

 

Has anyone tried Swepco 201 in their manual transmission? It’s the oil of choice in the vintage Porsche community.

 

South Western Power COmpany makes trans lube?

 

Its worth a try.

The Porsche folks use SWEPCO 201 for the 901 transmission, which can be described as vague, notchy, and somewhat temperamental. The 901 served its purpose for many years and typically works on the race track (which is the point). Definitely adds character to the pre-1987 911 driving experience.

 

Sounds expensive.

Knowing I'd be changing my gearbox oils at the end of the year, I'd order one quart at a time, as I could afford them, until I had enough to change fluids. Something like $20/quart for Redline last I put one in my cart. Can't imagine paying more than that.

 

How's your stick shift feel otherwise? Sloppy/floppy, or pretty tight? My Tacoma never needed it, so maybe Toyota finally upgraded that part, but on all my previous Toyota pickups, replacing the plastic bushing that sits at the seat of the stick shift made the transmission feel like new. They get thin, brittle, crack into pieces.

I do miss being able to fill my transmission through the shifter hole in the cab. Way easier than laying underneath, pumping.

 

Red Line is perfect, good stuff.

 

Shifting feels tighter in the cold temps. Especially 2nd gear until it warms up then feels like before. I'm not familiar with the plastic bushing you mentioned. I'll have to look it up to see if my year has it.

 

Seat and bushing. I'd guess you have them, but that doesn't mean they're worn out. Pretty easy to check.

 

If you're replacing those, consider getting marlin crawler upgraded ones.

 

I replaced those on my Tacoma that I had. They were basically worn to nothing. It made such a crazy difference and I had wished I knew about it sooner. In third gear you could shake the shifter like it was in neutral.

 

Yep. In older pickups it made my transmission feel like new. Not sure why the Tacoma's were fine even at really high mileage, but in previous trucks it took the transmission from feeling completely sloppy, to really tight. World of difference.

 

Syncromesh

 

I had several older Toyota PUs and replacing the seat and bushing really improved shifting if they were worn.