I have 30k on Royal Purple SyncroMax in my Mustang. I am completely satisfied, it improves the shift quality significantly over the factory fill.

Dave

 

The factory fluid is C SERIES MANUAL & DUAL DRY CLUTCH TRANSMISSION FLUID
Part Number - 68092630AA

Not easy to find out what exactly cross references.

 

http://www.dodge-dart.org/forum/dodge-dart-transmission/27849-15-c635-trans-fluid.html

Found this thread that gives some info about it.

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There is a very similar in name fluid, MOPAR C Series DDCT SAE 75W Hydraulic Fluid that is used in the fluid reservoir of a DDCT trans. I am wondering if this is where people got the 75W idea. I went through many pages of google trying to find the equivalent and got nowhere. 75W is awfully thick stuff. The hydraulic 75W in a DDCT is completely separate from the gear oil. Yes, the gear oil is the same Mopar C for both trans but I really doubt it would be thick 75W. That's what I use in my truck's rear diff.
Here is the pic from the FSM and may be the cause of the confusion:

 

There is a very similar in name fluid, MOPAR C Series DDCT SAE 75W Hydraulic Fluid that is used in the fluid reservoir of a DDCT trans. I am wondering if this is where people got the 75W idea. I went through many pages of google trying to find the equivalent and got nowhere. 75W is awfully thick stuff. The hydraulic 75W in a DDCT is completely separate from the gear oil. Yes, the gear oil is the same Mopar C for both trans but I really doubt it would be thick 75W. That's what I use in my truck's rear diff.
Here is the pic from the FSM and may be the cause of the confusion:

View attachment 89465

So, now that we are talking about transmission fluid changes... Hows about showing us the procedure to change it on the manual transmission darts???

 

21 - Transmission and Transfer Case / Manual, C635 / FLUID / Standard Procedure

FLUID DRAIN AND FILL

NOTE: It is acceptable to top-off fluid level in the case of fluid loss due to service of halfshaft, seal, etc.
•On vehicles equipped with 1.4 L engine, add fluid until it reaches bottom of the fill hole.
•On vehicles equipped with 1.4 L Turbo Engine, The minimum acceptable fluid level is 15 mm (0.6 in) below the bottom of the fill hole.
•On vehicles with 2.0 L and 2.4 L engines, add fluid until it reaches the rolled lower edge of the sloped ramp 40 mm (1.5 in) inside the threshold of the fill hole next to the differential ring gear carrier. This surface is approximately 8 mm (0.3 in) below the bottom of the fill hole.
•On vehicles with 2.0 L and 2.4 L engines, the minimum acceptable fluid level is 23 mm (0.9 in) below the bottom of the fill hole.


To fabricate a fluid level dipstick, cut a 15 mm (0.6 in) wide strip, length wise, from a common business card. At 30 mm (1.2 in) from one end, fold the strip to 90°. The short end of the strip is the dipstick and the long end is the handle. Insert the paper dipstick into the fill hole and press the handle end against the flattened threshold so the dipstick end turns downward into the sump near the differential carrier. Remove the paper dipstick and immediately measure the distance from the fold crease in the paper to the top of the fluid line. As time passes the paper will absorb the fluid and the witness mark the fluid left in the paper will become invalid. The distance from the fold to the fluid mark is the fluid level.

1.Raise vehicle on a suitable jack or hoist.

2.Remove the belly pan.

3.Place a suitable drain pan under transaxle.

4.Remove transaxle drain plug to allow the fluid to flow (1) into the drain pan until transaxle (2) is empty.

5.Install the drain plug and tighten to 25 N·m (18 lbs. ft.).

6.Using regulated 344 kPa (50 psi) compressed shop air or stiff bristle brush, clean the area around the fill plug to avoid contaminating the transaxle during the filling operation.

7.Remove the rubber fill plug (1) from the transaxle (2), located rearward and above the left halfshaft.

8.Fill the COLD transaxle with 1.7 l (1.8 qt.) of the proper fluid type. (Refer to 04 - Vehicle Quick Reference/Capacities and Recommended Fluids/Specifications) .

9.Install the fill plug.

10.Install the belly pan.

 

According to that other thread, the gear oil is 75w which sounds about right for a manual transmission.

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Maybe right for a 3 or 4 speed manual trans from 1970 but I really wonder if that's right for a modern 6 speed manual or DDCT. And let's not forget all the additives that might be missing in a straight 75W fluid.

 

Will do when I go to do it, just need to make a call on which fluid I'm going to use. Looks like Royal Purple, Amsoil, and Redline are all about the same quality and similar price.

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If you look closely at the pic, it has the part number on the bottle. Had to look a couple times before I saw it.

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If you look closely at the pic, it has the part number on the bottle. Had to look a couple times before I saw it. View attachment 89473

I would still be concerned about additives in the Mopar fluid that might not be in a straight 75W fluid or another brand that claims universal compatibility.

 

Looking like as long as it is 75w API GL4 it should work. That's kinda why I started the thread, was to see if anyone is using the aftermarket options to refill and having good luck.

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Sorry if I'm stepping on toes posting links to vendors, but this is what I'm seeing.

https://www.redlineoil.com/product.aspx?pid=45&pcid=7

http://www.amsoil.com/shop/by-produ...t/transmission-fluid/manual/manual-transmission-and-transaxle-gear-lube-75w-90/

http://www.royalpurpleconsumer.com/products/max-gear/

I'm with @alpinegreenneon not sure if there is some kind of additive that needs to go with these or not.

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I am not an automotive engineer. I am pretty sure that the Dart manual trans has fiberide synchros, not brass or bronze. The Neon SRT4 T850 had a huge issue with a friction modifier that should never been added because it ate the fiberide synchros. And that modifier was added because of a stupid tsb. The links to the above fluids claim them to be universally compatible. I am not sure I would want my trans to turn out to be the exception.

 

People on a Chevy Cruze Forum were saying that AMS Oil Synchromesh was the best to use on that car for a manual transmission, but I don't know what the best oil for the Dart would be.

 

I would have to go with @alpinegreenneon on this one... Dont put your transmission at risk. If there is no CLEAR evidence that the fluid from Mopar shares the same makeup as the other brands stick with the one you know will work correctly with your car!

 

If I understand correctly, the transmission fluid and hydraulic fluid are different fluids and not interchangeable despite both being SAE 75W API GL4 fluids.

 

Correct, there are two different part numbers and the one for the manual Dart says 75 W manual & DDC transmission Fluid. The one for the Dart DDCT clutch fluid reservoir is says that it's 75W hydraulic fluid.

68092638AA

68092630AA

Both the manual and DDCT use the 68092630AA 75W transmission fluid in the gear box of the trans.
ONLY the DDCT clutch fluid reservoir uses the 68092638AA 75W hydraulic fluid. Please note the last numeric digit in the part numbers are different. A hydraulic fluid does not need the same lubrication properties as a gear fluid. Brake fluid is a hydraulic fluid and you would never use that to lubricate gears. The two fluids should not be interchanged.

Please disregard my earlier post in this thread when I did not realize that the label on the bottle actually said 75W. While 75W is a rather thick viscosity, obviously the engineers that decided on that fluid specification know way more than I do. The fact that there are two different 75W fluids only accentuates the fact that different additives in each type can make a considerable difference.

 

FWIW, 75w hypoid gear oil is approximately the same viscosity at room temp as 10w motor oil. You can't compare viscosity of gear oil and motor oil by the SAE rating.

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I was helping another forum member in another thread:
http://www.dodge-dart.org/forum/dodge-dart-gt/45433-how-my-gt-has-gone-so-far.html

Found this NOTE in the FSM:

NOTE: If a fluid with anti-friction additive is used in a C-365 transmission the synchronizers will fail, requiring synchronizer replacement.

This is what I was referring to when I mentioned the T850 SRT4 trans. Since you have NO IDEA what is in the formulation of universal compatible 75W fluids, why risk it????

 

I understand what you're saying about potential damage caused by not running the right lubricant.

Still haven't heard from Dodge/FCA about options for aftermarket oils. *Shock* I did however find a company in the uk called Morris Lubricants that has a DCT formula that supposed to be compatible with the C635, http://www.morrislubricants.co.uk/products/auto/gear-transmission-oils/multitrans-dct.html
This could be really good news. Wouldn't run this brand, but it gives me hope that others will also work. Will keep you guys posted. Thanks for everyone's help.

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Royal purple suggests their Synchromax transmission fluid is compatible. Link to the cross reference here.

They state this fluid is compatible with all friction materials (which implies they don't use any anti-friction additives) and that it is safe with soft metals found in some transmissions. Product description here.

 

Out of curiosity, I looked up a price comparison.
@AllMoparParts.com
Fluid-C series transmission - Mopar (68092630AA)
List Price: $31.20 You Save: $9.69 (31% off) Sale Price: $21.51

Amazon
Royal Purple 01512 Synchromax High Performance Synthetic Manual Transmission Fluid - 1 qt.
Price: $19.15

Then I looked closer at what the link for the Royal Purple says and read this:
"Synchromax is recommended for manual transmissions that specify an automatic transmission fluid."

Automatic transmission fluid is more like a 5W30 motor oil not a 75W! The SRT4 Neon had ATF+4 from the factory and likely they are referring to that application. So who wants to save $2.36/qt and put possibly the wrong fluid in their trans?

 

Dude, I don't want to run the factory fluid. It wasn't designed for any kind of heavyduty/performance application. Based on some of the transmission horror stories I've seen on here, it doesn't sound like the factory fluid is very good.

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But the Dart is not really a performance car. The SRT version that never happened would have been a performance car. Why are you so sure that the problems with the manual trans are caused by the factory trans fluid? From my reading it seems like the CDV (clutch delay valve), the rear mount, and dealer incompetence are the actual problems.
Dude?? Can a 69 year old guy be a dude?

 

But the Dart is not really a performance car. The SRT version that never happened would have been a performance car. Why are you so sure that the problems with the manual trans are caused by the factory trans fluid? From my reading it seems like the CDV (clutch delay valve), the rear mount, and dealer incompetence are the actual problems.
Dude?? Can a 69 year old guy be a dude?

yes anyone, any age can be a dude...

 

Found some white papers on why aftermarket is better than stock fluids. I also understand that this isnt tests of the fluid I want to replace.
https://www.google.com/url?sa=t&rct...senseoil.com/G2457-GearOilWhitePaper.pdf&usg=AFQjCNHHHSLgrj6HbkTaP0o5TXd3WEqnYA

 

Fluids that have been ound to work well in Giuliettas (with the same C635 transmission) are:

Castrol syntrans Multivehicle 75w-90 GL4
Fuchs Titan Sintofluid FE SAE 75W

and the factory fill is Tutela Transmission Gearforce. that's a 7.1 cSt fluid at 100°C.

People are running overfilled gearboxesif they see more heavy use than just commuting. Since bottles are typically 1 litre, they dump in 2 bottles for a slight overfill.

I'll be changing to Castrol this summer, in my DDCT.

Red Line MTL would be a suitable candidate (especially in cold regions) as the cold viscosity is the same at -40° as the original fluid, as is the pour point. MTL is however thicker at operating temp which isn't an issue. Even Castrol which is double the viscosity of the original fluid at 100°c/212°F shits better. MTL however is rarer than hens teeth in Europe, and costs at least twice what the others cost.

 

Thank you, sir.

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All those trans fluids, Castrol Syntrans Multivehicle 75w-90 GL4, Fuchs Titan Sintofluid FE SAE 75W, and Tutela Transmission Gearforce, are in Europe, except the Red Line MTL. You can find info on all searching google. Good luck.

 

So I'm at about 50k miles now still running the factory transmission fluid... (I know, I know don't yell at me!) I noticed today driving that the feeling in the shifter is getting "different" and feels a bit sticky (for lack of a better word)After reading this thread completely and researching the different fluids out there... I feel as though a better transmis sion fluid might be a better idea for a daily driven and tuned dart. I am going to give the royal purple 01300 75w-90 a shot and see how it feels. I'll try and post some stuff when it comes in and let you guys know how it goes!

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I would go with the Royal Purple SyncroMax. It is made for manual transmissions and made a noticeable improvement in the shifting of my 15

 

+1 on the Syncromax

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Are you both running the syncromax now?