synthetic 75w 90 manual tran oil awesome!!!

Redline makes some awesome M/T gear oil. Probably what I'll end up going too. Not sure on the diffs though

 

I use Redline MTL in my tranny/transfer case, good stuff!

 

I would use

$34 Ford XT-M5-QS Full Synthetic Manual Transmission Fluid - 1 Quart , black

Ford XT-M5-QS for the trans, particularly if yours calls for a GL4 lube. You can buy it OTC at a Ford dealer. If they do some SVO parts business they'll know what it is, if they don't, they'll look at you like you have two heads. Be careful, and don't take substitutes! I've heard there are other lubes with similar nomenclature, but it's not the same mix. Guessing here, but I think your spec will be 75/90, but GL4. Using GL5 is not recommended if GL4 is called for, because GL4 is bronze synchronizer friendly, and GL5 is not.

I've used/recommended this to several in the autox / HPDE world and it made a nice difference for everyone who tried it. Even over Redline, Amsoil and RP. While I guess you could say it's a boutique lube (not available at big box parts houses and WalMart) you don't have to go mail order either.

But it's not cheap. Its worth doing if you either are hard on your transmission, want better shifting, or are willing to extend your OCIs.

If you are fairly easy on your vehicle, 50k OCI will be quite satisfactory; the 30k OEM recommendation is for dino.

For the rear, I'd use Mobil 1 in the correct wt/GL. Guessing that will be 75/90 GL5, but check your book first.

 

That's why so many of us love Redline MTL! Cheaper than the Ford fluid, too.

"Safe for brass synchros, as it lacks the reactive sulfurs found in most GL-5 oils that cause damage"

Redline MTL

 

Understood. I've used it. But you might want to re-read my 2nd para. Its better than Redline. Not just IMHO, but in testing by tribologists. The average user is fine w/dino. But if you are taking advantage of syn, go all the way!

 

They make MT-90 for manual transmissions and a regular 75w90 oil for gears (diffs and t-case). I've heard nothing but good things about their 75w90 as well.

 

Thanks gang, looks like I'll be checking into the Redline stuff,

I have lifetime oil changes thru my dealer as a perk from 2015 so I am seriously considering keeping this truck as long as we can.

BUT the other maintenance is up to me, lol...

Appreciate the responses.

There is something special about being in the 4-cyl forum,

 

A couple of years ago, I changed the dino transmission oil to valvoline synthetic 75w90 GL5. A short time later, it started grinding a bit when downshifting from 4 to 3 or 3 to 2. A couple of weeks ago, I changed the oil to MT-90 GL4. What a difference! The transmission now acts like it used to. Downshifting is smooth in all gears. I was surprised, but it worked for me.

 

Yep. I followed the lead by @clearwaterbill via a similar thread I had going a cpl weeks ago on this, but for my 3rd gen 6sp mt. Noticeable immediate improvement and has been getting better since.

 

Absolutely without the intention of being critical, I'll just say that I can't find reason in deciding to go with a less desirable lubricant due to the imo negligible cost difference of around $10 all-in spread across 30-50k miles. That could be made up for in clutching practices alone.

 

Amsoil in everything in mine. So far so good.

 

How fast do you go? I'm thinking of trying to stay below 65mph. I get 21+ mpg at speeds up to 80 which isn't bad.

AmsOil in everything for me. I used what they recommend.

 

My front and rear diffs and transfer case and transmission fluids need to be changed soon, STUPID thing is according to my owners manual I need THREE different types of oil! For Real?

I am going to seek info about this!

 

If I remember right off the top of my head, the manual trans takes GL4 rated oil and the diffs take GL5. It's not 'stupid', it's so that the components of each are protected against heat and wear, respectively.

This is a good article explaining the difference

https://www.linkedin.com/pulse/diff...l-5-gear-oils-manual-transmission-daniel-shi/

 

Use the same GL-5

$30 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 oil for the diffs and tcase, and use GL-3 or GL-4 75w-90 for the transmission. The diff doesn't care if it's 75w-85 or 75w-90.

It's interesting that the oil specs are different between the early 2nd gens and late 2nd gens. My 08 says to use GL-4 or GL-5 oil in the transmission and 80 weight, 90 weight, or 80w-90 in the differential.

 

Thanks for the info in the link, I just was able to read it. Makes good sense...
Guess I'll stick with wat my owners manual recommends as I may be keeping this truck until it or I die.

Gess stupid was to strong of a term,

I think the GL-5 stuff in the diffs was to help the diff and such right? I'm not all educated up on the differences in GL-4 vs GL-5 and such.


It would just be great if I could get one great synthetic for all four components.

 

I use the same GL5 fluid in the diffs and tcase but GL4 for the trans, so I only have to purchase 2 different kinds. I've got a 1st gen though, but I've never had any issues with it. Definitely use GL5 in the diffs though.

 

GL-4 for the tranny is recommended because GL-5 can eat the brass syncro's over time because of the high pressure additives that are in it.. So they say. Many dealers and some on this forum just use GL-5 in everything. I don't. I use Amsoil GL-4 in the tranny, their 75-90 in the transfer case and their 75-110 in the diffs. So far, so good. I use Amsoil because I hate getting under there and changing fluids. With Amsoil I can go at least twice the recommended intervals without changes. I'm up to 8500 miles on the engine oil and might be able to go 10,000 eventually and even though I don't have to, I'll change all the gear boxes next summer, have an oil analysis done on them and then decide how long I can run the gear boxes between changes. I'll probably have about 50,000 miles on the gear boxes by then. Maybe more. Amsoil says something like 150,000 miles or some other ridiculous number so I'll play it safe just like I do with the engine oil. I'll work upwards with the mileage between changes based on oil analysis.

No, I'm not an Amsoil dealer and even if I wanted to be one I wouldn't. No time for that hassle with my job. I just know Amsoil is one of the best out there and easier to get than many think.

 

Thanks bud, appreciate the info!

I’m looking into doing it in the next few weeks.

I’m not due an oil change just yet but would like to wait and knock it all out at the same time.

 

Redline makes several GL-4 for transmissions: MTL, MT-85 and MT-90. The MTL is 75W-80, MT-85 is 75W-85 and (shockingly) MT-90 is

$30 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90. The owners manual for my 2008 recommends 75W-90.