Redline MTL vs Motorcraft Full Synthetic Manual Transmission Fluid (XT/M5/QS)

[Don A.]

I have no idea what fluid is inside my manual right now, but I am curious to see what the Redline MTL will do for it. Service records show that that it was changed at the dealer (60k service). If it hasn't been done since, it needs to get done. It shifts great when warm, but is definitely a little stiffer and less compliant when cold.

I imagine just having new clean fluid is going to be an improvement from old. I have a feeling all the fluids in mine are all overdue and since it’s at 100,000 and I’ve decided to just change everything out for peace of mind. My diffs and TC are getting done this weekend.

 

[Rooscooter]

I recently bought the TJ in photo to the left. It's in unbelievable shape for a 15 year old Wrangler. Not a spot of rust and appears to have been off road very little. I'm going through it tailpipe to fog lamp. 1st was a new stereo (can't do the rest in the garage without some tunes!), second was new plugs and a coil rail (serious improvement in idol and acceleration) and today I swapped out the 6 Speed's fluid or Redline MTL. It was a decision between the Redline and Royal Purple's similar product. The local Jeep shop recommends these two as suitable replacements for the Mopar fluid.

The shifting is noticeably smoother and the syncros are pushing when they should. The Jeep has 90K on it and the drain plug looked like Bart's hair. The fluid was clear but it was obvious that the fluid had been in there a while.

....next up the Dana 44's.....then the TC.... then the brakes..... then maybe back to the sound system. I do have a small intermittent squeak in the front left wheel when I turn to the right. Gotta chase that one down too.

 

[Longjeeprubi05]

Since no one here is a petroleum engineer who has tested both products, I doubt you'll get a meaningful comparison of the two. Did you try Redline MTL in your NSG370? It receives consistently good reviews in the NSG370 and NV3550. I dunno why you'd be tempted to try Ford's without knowing if it meets the NSG370 requirements as Redline's MTL definitely does.

I am about to change my 05 rub trans and transfer for the first time. What weight redline mtl is used?
Thanks

 

[Jerry Bransford]

I am about to change my 05 rub trans and transfer for the first time. What weight redline mtl is used?
Thanks

Redline MTL has just its one normal 75W-80 viscosity.

 

[Rickyd]

Not knowing anything about transmissions, I have no clue what could be wrong. I drove another guys 6-speed from the Same year and it was definitely smoother. What could be wrong?

edumacate yourself

 

[Longjeeprubi05]

Redline MTL has just its one normal 75W-80 viscosity.

Any recommendations for the NVG 241 transfer case fluid?

 

[Jerry Bransford]

Any recommendations for the NVG 241 transfer case fluid?

Any good quality ATF.

 

[Longjeeprubi05]

Any good quality ATF.

Thanks

 

[Don A.]

I figure I should update this I case any stumbles on it. I ended up switching to Amsoil Synchromesh trans fluid. That’s what required for the NSG370 and it works great. No issues.

 

[cb4017]

I figure I should update this I case any stumbles on it. I ended up switching to Amsoil Synchromesh trans fluid. That’s what required for the NSG370 and it works great. No issues.

What made you decide to change from the MTL? Problems?

I used the Amsoil MTF in my 08 JKU and had no problems with it.

My TJ is due and trying to decide what to go with. I had almost decided on the Redline until I saw your post.

 

[CJ with a TJ]

I just used the Redline for the first time, and I'm a fan. That weird grind from 1st to 2nd is gone now, the shifting is much more smooth. No idea what I was using before, but it wasn't anything special.

 

[Don A.]

What made you decide to change from the MTL? Problems?

I used the Amsoil MTF in my 08 JKU and had no problems with it.

My TJ is due and trying to decide what to go with. I had almost decided on the Redline until I saw your post.

Hi. So in short, yes. I had problems.

My TJ is an ‘06. The NSG370 transmission is designed to use synchromesh fluid. It’s “basically” automatic transmission fluid; thin viscosity…(like ATF). The Redline is a gear lube is gear lube, so it’s thick like honey. A lot of very knowledgeable experienced Jeep owners told me redline was the way to go cause that’s what they used for years. But they weren’t as experienced with the later models. The NSG370 6sp manual was introduced to our TJs in 2005. So there’s 3 different manual transmissions that were used Depending on the year.

I live in Michigan so when the weather is warm my jeep would shift fine but on cold mornings or in the winter the redline was so thick I could barely shift gears. It was almost undrivable. I finally just followed the FSM and used what was recommended (by Jeep) and it shifts smoothly.
Amsoil is the best in my opinion. The website has a really good breakdown of the fluid type and quantity needed for each system by vehicle. I’d plug in your model info and see what they recommend for your year of TJ.

I’d definitely recommend using any brand of synchromesh trans fluid over a gear oil in the 6sp NSG370.

 

[Don A.]

I just used the Redline for the first time, and I'm a fan. That weird grind from 1st to 2nd is gone now, the shifting is much more smooth. No idea what I was using before, but it wasn't anything special.

It depends on the year of your jeep. The 6sp NSG370 specifies synchromesh fluid but I’m pretty sure the earlier 5sp manuals can use redline no problem.

 

[JustDandee]

Redline user here I just used the by application on the website and change out the everything- always have been happy with their product. Including the product description note the synchromesh reference.l and to use GL4 not GL5

MTL 75W80 GL-4 - QUART​

• Popular for BMW, Honda/Acura, Ford Focus, late-model Mini Cooper, Land Rover/Range Rover LT77S, Mitsubishi, Dodge & Jeep NV1500, NV3500, NV3550 and NV5600 truck transmissions
• Popular replacement for and improvement over GM Synchromesh® (#12345349), Auto-Trak II® (#12378508) and Chrysler spec MS-9224
• Safe for brass synchros, as it lacks the reactive sulfurs found in most GL-5 oils that cause damage
• Offers quicker shifts, A perfect synchronizer coefficient of friction
• Eliminates notchy shifting, even when cold
• High performance gear protection and longer synchro life
• Satisfies the gear oil viscosity requirements of 75W, 80W and motor oil viscosities of SAE 30, 10W30 and 5W30
• Recommended for GL-1, GL-3 and GL-4 applications as well as where most special synchromesh fluids are specified

 

[OldBuzzard]

Red Line MTL is "synchromesh" lube, and GL-4, and Chrysler MS9224, which Chrysler recommends for the NSG370.

 

[Don A.]

Red Line MTL is "synchromesh" lube, and GL-4, and Chrysler MS9224, which Chrysler recommends for the NSG370.

View attachment 619375

Redline user here I just used the by application on the website and change out the everything- always have been happy with their product. Including the product description note the synchromesh reference.l and to use GL4 not GL5

MTL 75W80 GL-4 - QUART​

• Popular for BMW, Honda/Acura, Ford Focus, late-model Mini Cooper, Land Rover/Range Rover LT77S, Mitsubishi, Dodge & Jeep NV1500, NV3500, NV3550 and NV5600 truck transmissions
• Popular replacement for and improvement over GM Synchromesh® (#12345349), Auto-Trak II® (#12378508) and Chrysler spec MS-9224
• Safe for brass synchros, as it lacks the reactive sulfurs found in most GL-5 oils that cause damage
• Offers quicker shifts, A perfect synchronizer coefficient of friction
• Eliminates notchy shifting, even when cold
• High performance gear protection and longer synchro life
• Satisfies the gear oil viscosity requirements of 75W, 80W and motor oil viscosities of SAE 30, 10W30 and 5W30
• Recommended for GL-1, GL-3 and GL-4 applications as well as where most special

Well, I can say from personal experience that Redline did not play nice in my transmission.
I think I ran it for roughly two years and in the summer or general warmer months it worked okay. But once the temperature drops the difference is night and day. It was barely shiftable in winter. If using it down south or the southwest it’s probably way better being warmer and all.

Redline is not a synchromesh fluid. It’s way more thick or viscous. It’s “safe” for synchronizers but it’s not made for the NSG370.

After I put the type of fluid the manual calls for in it, it shifts great and I don’t have issues shifting come January. I first used some cheap pennsoil fluid just to try it out before buying something pricier. Huge improvement. Amsoil has by far the most data from testing available for their products than any other company out there so I switched to them.

Just put in what the manual calls for At least, that’s the moral of the story as I came to understand it lol.

Not being argumentative or anything. Just my experience with my jeep.

 

[CherokeeKid]

I figure I should update this I case any stumbles on it. I ended up switching to Amsoil Synchromesh trans fluid. That’s what required for the NSG370 and it works great. No issues.

Hi. So in short, yes. I had problems.

My TJ is an ‘06. The NSG370 transmission is designed to use synchromesh fluid. It’s “basically” automatic transmission fluid; thin viscosity…(like ATF). The Redline is a gear lube is gear lube, so it’s thick like honey. A lot of very knowledgeable experienced Jeep owners told me redline was the way to go cause that’s what they used for years. But they weren’t as experienced with the later models. The NSG370 6sp manual was introduced to our TJs in 2005. So there’s 3 different manual transmissions that were used Depending on the year.

I live in Michigan so when the weather is warm my jeep would shift fine but on cold mornings or in the winter the redline was so thick I could barely shift gears. It was almost undrivable. I finally just followed the FSM and used what was recommended (by Jeep) and it shifts smoothly.
Amsoil is the best in my opinion. The website has a really good breakdown of the fluid type and quantity needed for each system by vehicle. I’d plug in your model info and see what they recommend for your year of TJ.

I’d definitely recommend using any brand of synchromesh trans fluid over a gear oil in the 6sp NSG370.

According to the product data sheets, Amsoil has a viscosity ~2.65 times higher at -40°C. Redline has a slightly lower pour point temperature as well. KV at 40°C and 100°C are about the same between the two.
Amsoil will be the thicker of the two at low temperatures and nearly identical to Redline at high temps.

https://www.redlineoil.com/Content/files/tech/MTL_GO_PROD_INFO_2020.pdf
https://amsoilcontent.com/ams/lit/databulletins/g2080.pdf