Which Transmission Fluid is best?

[MADMODDER]

2010, Ranger Sport, 4x4, 5 speed manual. I believe I have the M5OD-R4 transmission but I dont KNOW for sure. Hopefully somebody here can tell me.

Is oem fluid the best or should I look at Redline or Royal Purple?

Also, for the fill and drain plugs, is there a crush washer that seals? Are they one time use type plugs like the engine oil drain plug. What's the deal with them?
And tq spec if somebody can find that for me as I was not able to.

Thanks in advance.

EDIT- if you do not want to read through 6 pages of my newbness, for the diff I've gone with this.

75W140NS GL-5 Gear Oil

Contains extreme pressure additives like our 75W140 GL-5 oil, but lacks friction modifiers to balance slipperiness

www.redlineoil.com

And for transmission and tranfercase fluid.

D4 ATF

Our most versatile ATF, use where Dexron III®, Dexron II®, Mercon® and Mercon V® fluids are recommended, provides a GL-4 level of gear protection

www.redlineoil.com

 

[Dirtman]

You only use an oil drain plug once?

The fill and drain plugs are NPT thread which means the threads have a tiny taper to them which makes them tighter and tighter the more the plug is inserted. This is how they seal. Unless you lose one, they are are good for life.

Ford wouldn't design something and then use sub standard fluids in it. Motorcraft mercon V is excellent fluid and what I would recommend. You wont gain anything using overpriced stuff like royal purple.

 

[adsm08]

You have an M5OD-HD.

The R4 was used for only a year or two, in 4-door Explorers, for the South American market. To find one in the US is EXTREMELY rare. I think US usage of the R4 was something like <2% production for the 2002 MY only.

The transmission uses crush washers on the fill and drain plugs. They are not torque critical, which means that tight enough is tight enough, too tight is broke. I know someone will get on my case about bolt fatigue from not using the torque spec, but these are fasteners that are meant to be tightened down only two or three times over the vehicle's designed life span. You will not fatigue them beyond the point of reuse unless you break one.

Motorcraft fluid is good, some people report better results with Redline, almost nobody I have talked to liked Royal Purple better than the factory stuff, unless they had an earlier version of the trans.

Engine oil drain plugs, even the ones with the integrated gasket like the 4.0 SOHC has, are reusable. They can be reused until they start to leak. The only single-use drain plug Ford ever made was used on the early 6.7L diesel and were made of plastic. Those ones don't stay tight if you reuse them.

 

[Josh B]

Is it the same for the R1 M50D ? I've been using Mercon V but somewhere got the impression I should use plain Mercon in it, anybody?

 

[adsm08]

The R1 and the HD are functionally the same transmission, with the same internals. The HD has an extra bell bolt hole.

Early R1 units, built pre-95 seem to not respond as well to the use of Merc V. R1 units built 95 and up, as well as all HD units seem to handle Merc V better. Some surmise it is because Merc V is "too slippery" for the older blocking rings, I personally think it is something in the formulation of the fluids. Something the original stuff had that the newer stuff doesn't, that the metals became dependent on, kind of like how if you use ether to get an engine started for too long eventually the rings dry out and it won't start without it.

 

[MADMODDER]

You only use an oil drain plug once?

The fill and drain plugs are NPT thread which means the threads have a tiny taper to them which makes them tighter and tighter the more the plug is inserted. This is how they seal. Unless you lose one, they are are good for life.

Ford wouldn't design something and then use sub standard fluids in it. Motorcraft mercon V is excellent fluid and what I would recommend. You wont gain anything using overpriced stuff like royal purple.

According to Ford and the "Work Shop Manual" book, the drain plugs are good for 2 uses because of the integrated seal. I just replace it every time. It's only like $4 at my local dealer.

I know what NPT is but, as a newbie to this forum, I appreciate you explaining it like I'm 5. Sincerely.

According to the next guy, they have a crush washer.
Are they NPT and use a crush washer?

You have an M5OD-HD.

The R4 was used for only a year or two, in 4-door Explorers, for the South American market. To find one in the US is EXTREMELY rare. I think US usage of the R4 was something like <2% production for the 2002 MY only.

The transmission uses crush washers on the fill and drain plugs. They are not torque critical, which means that tight enough is tight enough, too tight is broke. I know someone will get on my case about bolt fatigue from not using the torque spec, but these are fasteners that are meant to be tightened down only two or three times over the vehicle's designed life span. You will not fatigue them beyond the point of reuse unless you break one.

Motorcraft fluid is good, some people report better results with Redline, almost nobody I have talked to liked Royal Purple better than the factory stuff, unless they had an earlier version of the trans.

Engine oil drain plugs, even the ones with the integrated gasket like the 4.0 SOHC has, are reusable. They can be reused until they start to leak. The only single-use drain plug Ford ever made was used on the early 6.7L diesel and were made of plastic. Those ones don't stay tight if you reuse them.

Ok. Sweet. Thanks for clearing up which trans I have.
Are the plugs not NPT as stated in the previous comment?

I'm always mindful of torque specs. "Do it right or do it twice." I mean, I got 3 tq wrenches, 2 of them snap on. I will get my monies worth out of them.

I have this super skookum book "Ford Work Shop Manual". That says the engine oil drain plug is only good for 2 uses. I just replace it at every use because it's only like $4 at my local dealer.

I'm a retailer for redline, it's likely no more expensive for me to get that than OEM fluid. As long as it doesn't cause issues, I may run with that.

Do you have any insight on the transfer case and differentials? Fluids and covers for the diffs? I was looking at the G2 cover.

 

[Dirtman]

Adsm knows more than me so if he says they have a crush washer I'd believe him. All the old manuals and diffs I've messed with, the fill plugs are usually npt so I assumed it was the same on the m5od. But again... listen to Adsm lol.

 

[4x4junkie]

Mercon V is actually what is specified for 2008 & up M5OD, so in theory that should be fine in a '10 (a synthetic like Royal Purple or Redline should be fine also... I put RP in my '90 and it seemed like maybe I picked up a teensy bit more power to the wheels in all gears but 4th, but it could also be placebo effect, I'm not sure... I've not dyno'ed it).

The fill & drain plugs on the M5OD do use crush washers. I've reused them at least half-dozen times w/o issue (my factory Ford service books also make no mention of needing to replace any washers or seals on the M5OD when changing fluid). The only NPT plugs that come to mind are fill plugs for the axles, and the t-case fill & drain.

Early R1 units, built pre-95 seem to not respond as well to the use of Merc V. R1 units built 95 and up, as well as all HD units seem to handle Merc V better. Some surmise it is because Merc V is "too slippery" for the older blocking rings, I personally think it is something in the formulation of the fluids. Something the original stuff had that the newer stuff doesn't, that the metals became dependent on, kind of like how if you use ether to get an engine started for too long eventually the rings dry out and it won't start without it.

Something present in Mercon that Mercon V doesn't have? I s'pose that's a possibility... Except that putting Mercon (Dex/Merc) back in the trans after it having seen Merc V didn't seem to resolve the issue (not fully anyway). My thought is there's something in Merc V that impregnates into the soft metals of the synchros and forms a lubricating layer on them that reduces their friction too much, affecting their function.

 

[adsm08]

I know what NPT is but, as a newbie to this forum, I appreciate you explaining it like I'm 5. Sincerely.

Sometimes we put information out there that the person we are responding to may know, but we do it for the next guy who finds the thread and may not.

Ok. Sweet. Thanks for clearing up which trans I have.
Are the plugs not NPT as stated in the previous comment?

Not on the trans. The only NPT plugs Ford uses are the ones that take the 3/8 square drive.

I'm always mindful of torque specs. "Do it right or do it twice." I mean, I got 3 tq wrenches, 2 of them snap on. I will get my monies worth out of them.

I have this super skookum book "Ford Work Shop Manual". That says the engine oil drain plug is only good for 2 uses. I just replace it at every use because it's only like $4 at my local dealer.

I have that book too. All of them in fact. If you want to get out the torque wrench for every tiny fastener and replace the drain plug every time, more power to you.

I also have over a decade of day-in day-out practical experience that tells me most of those torque specs were issued because the legal department said to and not because it is critical to torque them exactly to spec each time, and that those drain plugs can go 100K miles or more before they start to leak.

I'm a retailer for redline, it's likely no more expensive for me to get that than OEM fluid. As long as it doesn't cause issues, I may run with that.

Do you have any insight on the transfer case and differentials? Fluids and covers for the diffs? I was looking at the G2 cover.

If it is an electric shift transfer case I'd use actual transfer case fluid. If it is manual either t-case fluid or Mercon are OK.

For the diffs just use a high quality gear oil of the correct weight, and a factory diff cover. The shape of the cover makes large contributions to the oil flow and heating/cooling characteristics of the diff, and many after-market covers give up that flow characteristic in favor of a larger sump, and end up working the oil harder and running the diff hotter.

 

[Ranger850]

what does NPT stand for? I get the explanation, just want to know what "NPT" is

 

[ford4wd08]

what does NPT stand for? I get the explanation, just want to know what "NPT" is

National pipe thread
National Pipe Thread Taper (NPT) is a U.S. standard for tapered threads used on threaded pipes and fittings. In contrast to straight threads that are found on a bolt, a taper thread will pull tight and therefore make a fluid-tight seal.

 

[Ranger850]

National pipe thread
National Pipe Thread Taper (NPT) is a U.S. standard for tapered threads used on threaded pipes and fittings. In contrast to straight threads that are found on a bolt, a taper thread will pull tight and therefore make a fluid-tight seal.

thank you

 

[fastpakr]

If it is an electric shift transfer case I'd use actual transfer case fluid. If it is manual either t-case fluid or Mercon are OK.

Why does the shift mechanism affect what fluid you choose to use?

 

[Shran]

Why does the shift mechanism affect what fluid you choose to use?

I'm questioning that too, aside from the motor on the back... the t-case guts are virtually identical.

I have reused the fill plugs many, many times and only replace them if they're rounded off. Same with oil drain plugs.

 

[MADMODDER]

Mercon V is actually what is specified for 2008 & up M5OD, so in theory that should be fine in a '10 (a synthetic like Royal Purple or Redline should be fine also... I put RP in my '90 and it seemed like maybe I picked up a teensy bit more power to the wheels in all gears but 4th, but it could also be placebo effect, I'm not sure... I've not dyno'ed it).

The fill & drain plugs on the M5OD do use crush washers. I've reused them at least half-dozen times w/o issue (my factory Ford service books also make no mention of needing to replace any washers or seals on the M5OD when changing fluid). The only NPT plugs that come to mind are fill plugs for the axles, and the t-case fill & drain.

Not NPT on the trans. Got it.
I find it weird that the books dont advise to replace crush washers. They only crush once and that's it. Like stretch bolts. They can only get so tight until they give and over stretch which decreases the clamping/fastening capabilities.

I have that book too. All of them in fact. If you want to get out the torque wrench for every tiny fastener and replace the drain plug every time, more power to you.

I also have over a decade of day-in day-out practical experience that tells me most of those torque specs were issued because the legal department said to and not because it is critical to torque them exactly to spec each time, and that those drain plugs can go 100K miles or more before they start to leak.



If it is an electric shift transfer case I'd use actual transfer case fluid. If it is manual either t-case fluid or Mercon are OK.

For the diffs just use a high quality gear oil of the correct weight, and a factory diff cover. The shape of the cover makes large contributions to the oil flow and heating/cooling characteristics of the diff, and many after-market covers give up that flow characteristic in favor of a larger sump, and end up working the oil harder and running the diff hotter.

So not NPT on the trans. Got it.

I dont use tq specs on ever nut and bolt. I'm not going to use it for the windshield wiper fluid reservoir.

But something that holds in crucial oil, I'm willing to follow the book.
You have the book? I'm a VW mechanic. Ford is kinda new to me. Is the aforementioned book a good starting point or did I waste my money?

This is where I need my hand held and Explain it like I'm 5.

What do you mean by "Electric shifter"? I have a 5speed manual transmission. Do you mean to put it into 4x4? For that, I have a dial in the cab. I'm going to assume that's what you're talking about. "2hi(?)", "4hi" & "4low". I think that is electric, unless its turning cable and pulleys to change between them.
Assuming it is electric, what brand do you recommend I go with? Do you know if Redline sells something for it?

Diff cover. I watched a thing by Banks about diff cover shapes. All the big names with larger capacity having flat plains making the oil work harder and whatnot. So I've been looking into rounder ones.

The G2 is pretty round. You dont think it's good enough?

https://www.autoanything.com/drivetrain-differentials/77A8524A3944283.aspx?kc=GOOGADW&DZID=PLA_g_1776971472_74555083092_8524-3944283_m&utm_source=g&utm_medium=cpc&utm_campaign=1776971472&utm_content=74555083092&utm_product=8524-3944283&gclid=CjwKCAjwtO7qBRBQEiwAl5WC2yZB83_HssV6XOZ7mciBS-Ryf0cvTDzcKAjzZP0EypOePsxGaIrHyBoC3A0QAvD_BwE

If not that then how about the mustang "Ford Performance" diff cover. That's aluminum and finned and round.

https://www.cjponyparts.com/ford-racing-rear-differential-cover-finned-aluminum-with-cooler-ports-8-8/p/M4033KA/?year=2010&gclid=CjwKCAjw1_PqBRBIEiwA71rmtXltIQTUFtUqHxCL9ZxWQ7E8z7Fj-Thft3Kg9Yzi8fbp5niUn_lbpRoC44MQAvD_BwE

If I'm just trying to re-invent the wheel, and all of this has been covered in depth in another thread, please let me know and share a link. I'll just go read that. But I dont see how atleast the "Ford Performance" cover is not better.

Diff oil. What do you mean by "high quality"? Like redline 75w90 full synethic gear oil? Or is OEM Ford fluid quality?

One more thing. Diff cover sealant. Or is it a gasket? I looked around and, I'm trying to keep up on different codes and MY they were on, but I read some 8.8 covers used a gasket from the factory while other used a clear silicone and yet OTHERS use the same OEM grey silicone that is used on the (I think) 12" diff for the 7.3 international engine(?). I dont know. 12" different sounds freaking huge so I'm probably wrong on that. However, that 7.3 is a beast.

Not to blow my own horn but I'm pretty mechanical savy. I've been doing the VW thing since I was a wee lad. My dad brought me up on aircooled VWs. I learned how to adjust valves on them when I was 10 or 11 and it's been down hill from there lol. I rebuilt a 5 speed tranny, from an '88 Ranger XLT with the 2.9 V6, my Junior year in hs. I've built 4bangers and big blocks. Petrol and diesel. 5 and 6 speed, FWD, RWD, AWD. Hadn't touched autos (other than DSG fluid changes). Now I have my own house and a 2 car garage that's filled with tools. I have a 30g air tank with 1" hose, 1/2" and 3/4" IR impacts, 20ton hydraulic press, engine hoist and stand, 4 tool boxes. The list goes on. Now. I'm not claiming to be a professional and it seems you're the real deal. Im just letting you know, I can do work and I take pride in my work manship. Now, I know these are apples and nazi oranges, (Ford and VW) but there are a good handful of OEM VW/Audi fluids are quality and hard to beat. Just a little insight why I'm going down this rabbit hole of oils and whatnot.