Notices
1973 - 1979 F-100 & Larger F-Series Trucks Discuss the Dentsides Ford Truck
Sponsored by:
Sponsored by: Moser

Adding ATF C6?

Thread Tools
 
Search this Thread
 
Old May 3, 2024 | 08:54 PM
  #1  
Deadbuck's Avatar
Deadbuck
Thread Starter
|
Tuned
5 Year Member
Liked
Joined: Apr 2018
Posts: 286
Likes: 40
Adding ATF C6?

Fluid level is low. I want to add some more fluid. I have no clue what fluid was in there when I purchased the vehicle. Is there anyway to tell the difference in fluids?

Half the websites say you can not mix Type F and Dexron at all ever or it will destroy the transmission. The other websites say no problem mixing.

Should I just add some type F? Should I just wait and get the fluid changed? Is it ok to drive it a little low? It’s been flaring between 2-3 gear recently.
 
Reply
Old May 3, 2024 | 09:27 PM
  #2  
tbear853's Avatar
tbear853
Hotshot
20 Year Member
Shutterbug
Loved
Community Favorite
Joined: Feb 2004
Posts: 10,836
Likes: 2,612
From: The Shenandoah Valley
What year model C-6 would help, as would reading the dip stick, Let us know. I "think" was about 1976 or 7 they changed the spec. Type F was earlier, has different friction.




Dex/Merc is a good sub for the CJ spec ...I was cautioned to base it on initial fill, my '77 was original with the CJ fluid and never been rebuilt.
 
Reply
Old May 4, 2024 | 12:48 AM
  #3  
440 sixpack's Avatar
440 sixpack
Lead Driver
5 Year Member
Photogenic
Photoriffic
Community Builder
Joined: Oct 2018
Posts: 7,893
Likes: 2,371
You can mix DEX and Type F. they're basically the same oil it's the additives that differ,

You should be using type F, other oils can cause more slippage my trans guru says.
 
Reply
Old May 4, 2024 | 06:51 AM
  #4  
Deadbuck's Avatar
Deadbuck
Thread Starter
|
Tuned
5 Year Member
Liked
Joined: Apr 2018
Posts: 286
Likes: 40
Originally Posted by tbear853
What year model C-6 would help, as would reading the dip stick, Let us know.
dip stick says ESP-M2C138-CJ oil
 
Reply
Old May 4, 2024 | 07:12 AM
  #5  
tbear853's Avatar
tbear853
Hotshot
20 Year Member
Shutterbug
Loved
Community Favorite
Joined: Feb 2004
Posts: 10,836
Likes: 2,612
From: The Shenandoah Valley
CJ had a yellow look, but as I understood it from an industry guy,it used whale oil as an ingrediant, it is "No More". Dex III/Merc or just "Dex/Merc" is good, and I still have some saved. Searches now indicate Mercon or Mercon V is OK.

I've never tried type F in mine, nor will I. Knew a guy who did, it changed to harsh shifting. Don't know what long term effects were.
 
Reply
Old May 4, 2024 | 07:58 AM
  #6  
Deadbuck's Avatar
Deadbuck
Thread Starter
|
Tuned
5 Year Member
Liked
Joined: Apr 2018
Posts: 286
Likes: 40
Do you think I would be ok to add a quart of type F for the short term until I can get the fluids changed or just wait it out and baby it if I need to drive it?
 
Reply
Old May 4, 2024 | 08:22 AM
  #7  
Rubiranch's Avatar
Rubiranch
Logistics Pro
Joined: Jun 2004
Posts: 4,790
Likes: 3,401
From: South Central Utah
Same topic, different thread. Check the last comment.

ESP-M2C138-CJ Fluid Alternative

I do know my '76 PS likes Type-F better than PS fluid.
My 2007 Lincoln calls for Mercon V.
I'm guessing it would work for a C6 too.
 
Reply
Old May 4, 2024 | 08:23 AM
  #8  
Rubiranch's Avatar
Rubiranch
Logistics Pro
Joined: Jun 2004
Posts: 4,790
Likes: 3,401
From: South Central Utah
Originally Posted by Deadbuck
Do you think I would be ok to add a quart of type F for the short term until I can get the fluids changed or just wait it out and baby it if I need to drive it?
If you don't know what's in there I'd use Type F.
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

Top 10 Fords at 2026 Carlisle Ford Nationals

 Joe Kucinski
story-1

3 Best / 3 Worst Parts of Modern Ford Ownership

 Brett Foote
story-2

10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

 Pouria Savadkouei
story-3

Every 2026 Ford Engine Explained

 Brett Foote
story-4

10 Ugly Ford Trucks That We Still Kinda Love

 Joe Kucinski
story-5

10 Things Every Truck Owner NEEDS (2026 Edition)

 Michael S. Palmer
story-6

Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

 Verdad Gallardo
story-7

Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

 Joe Kucinski
story-8

2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

 Brett Foote
story-9

Top 10 Ford Truck Tragedies

 Joe Kucinski
Old May 4, 2024 | 09:53 AM
  #9  
440 sixpack's Avatar
440 sixpack
Lead Driver
5 Year Member
Photogenic
Photoriffic
Community Builder
Joined: Oct 2018
Posts: 7,893
Likes: 2,371
The main difference between F and the others is the slippage you'll get. unless you're drag racing or heavy towing you'd probably never notice the difference, older Ford automatics were designed for type F. just do it.
 
Reply
Old May 4, 2024 | 02:04 PM
  #10  
beardedcap's Avatar
beardedcap
Tuned
Joined: Jun 2018
Posts: 458
Likes: 123
From: Arkansas
Originally Posted by 440 sixpack
The main difference between F and the others is the slippage you'll get. unless you're drag racing or heavy towing you'd probably never notice the difference, older Ford automatics were designed for type F. just do it.
i’d verify, I know they changed to mercon in 77. The former Ford trans engineer guy that posts on this forum, Mark Kovalsky is constantly adamant about using the right one. Afaik the clutch material is different depending on which one it uses. I know my 82 bronco took mercon
 
Reply
Old May 4, 2024 | 02:46 PM
  #11  
440 sixpack's Avatar
440 sixpack
Lead Driver
5 Year Member
Photogenic
Photoriffic
Community Builder
Joined: Oct 2018
Posts: 7,893
Likes: 2,371
Yes they changed in the late 70's. Op didn't say what year he has so since he was talking trpe F i assumed it was an earlier one. maybe not.

I wouldn't be afraid to use Type F in any c6 but if it calls for mercron that's what I'd use. seems like DEX II III is what substitutes for if I recall.
 
Reply
Old May 5, 2024 | 09:57 AM
  #12  
Rubiranch's Avatar
Rubiranch
Logistics Pro
Joined: Jun 2004
Posts: 4,790
Likes: 3,401
From: South Central Utah
When a C6 gets rebuilt I would have to think the clutches and seals would be upgraded to accept the newer fluids.
 
Reply
Old May 5, 2024 | 11:19 AM
  #13  
Viper Pilot's Avatar
Viper Pilot
Fleet Mechanic
Photogenic
Photoriffic
Liked
Loved
Joined: Feb 2022
Posts: 1,377
Likes: 709
I’m having trouble understanding why this is such an ordeal. Just fill the darn thing with some type of fluid. Don’t run it low and “baby” it. Even under normal load you’ll smoke clutch packs due to lack of fluid.

Honestly, I don’t know why you even want to change the fluid. If it smells burnt, your trans is done anyway. No amount or type of fluid is going to fix it. In fact, when a transmission is older or on the way out you’ll make the situation worse by changing the fluid because you just drained out all of the friction material from the clutches that was suspended in the fluid and helping them to apply. Add something in there to the appropriate level for now. Later, just drop the pan for a filter change and refill again. If the fluid is burned, you’re in for a rebuild eventually no matter what.
 
Reply
Old May 5, 2024 | 06:50 PM
  #14  
Deadbuck's Avatar
Deadbuck
Thread Starter
|
Tuned
5 Year Member
Liked
Joined: Apr 2018
Posts: 286
Likes: 40
Originally Posted by Viper Pilot
I’m having trouble understanding why this is such an ordeal. Just fill the darn thing with some type of fluid. Don’t run it low and “baby” it. Even under normal load you’ll smoke clutch packs due to lack of fluid.

Honestly, I don’t know why you even want to change the fluid. If it smells burnt, your trans is done anyway. No amount or type of fluid is going to fix it. In fact, when a transmission is older or on the way out you’ll make the situation worse by changing the fluid because you just drained out all of the friction material from the clutches that was suspended in the fluid and helping them to apply. Add something in there to the appropriate level for now. Later, just drop the pan for a filter change and refill again. If the fluid is burned, you’re in for a rebuild eventually no matter what.
Half of the stuff I read online said Do Not Mix atf fluids. The other said no problem to mix.

I can’t get a good read on the dipstick. Wiped clean, reinstall and remove and fluid is all up and down the dipstick. No idea how much is in there.
 
Reply
Old May 5, 2024 | 06:55 PM
  #15  
beardedcap's Avatar
beardedcap
Tuned
Joined: Jun 2018
Posts: 458
Likes: 123
From: Arkansas
Originally Posted by Deadbuck
Half of the stuff I read online said Do Not Mix atf fluids. The other said no problem to mix.

I can’t get a good read on the dipstick. Wiped clean, reinstall and remove and fluid is all up and down the dipstick. No idea how much is in there.
when are you checking it? While running and hot right? it can be hard to see but I know it's doable. It'll only be hard if you just added fluid through the dip stick tube and it will take a while for it to all run down into the pan
 
Reply



All times are GMT -5. The time now is 01:10 AM.

story-0
Top 10 Fords at 2026 Carlisle Ford Nationals

Slideshow: Top 10 Fords at 2026 Ford Nationals

By Joe Kucinski | 2026-06-09 11:10:08


VIEW MORE
story-1
3 Best / 3 Worst Parts of Modern Ford Ownership

Based on years of owning multiple modern Ford products.

By Brett Foote | 2026-06-09 10:53:36


VIEW MORE
story-2
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

SPONSORED: From muddy boots to rain-soaked cargo, these upgrades address some of the most common frustrations Ford truck owners face every day.

By Pouria Savadkouei | 2026-06-08 18:50:34


VIEW MORE
story-3
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-4
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-5
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-6
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE
story-7
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-8
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE
story-9
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE