Best trans fluid for the 3650?

[Mustang5L5]

Since i have to change a leaking rear seal, i am gonna change the fluid as well.


What's the best for the 3650? Mobil 1 synthetic ATF, Motorcraft synthetic ATF or royal purple??


I've never had the fix done as my clunk isn't all that bad. However since my rear seal has been leaking for a while i'm sure i'm low on fluid as it clunks a little more often these days

 

[SeventyMach1]

GM Syncromesh.

 

[Mustang5L5]

I prefer not to run GM synchromesh.

 

[40th GT]

I've heard no complaints about Mobil1 ATF.

 

[SeventyMach1]

I prefer not to run GM synchromesh.

Why?

 

[Mustang5L5]

Why?

Because Tremec claims it eats away at the materials used in the synchro linings and leads to premature wear. Only their 3550 line uses GM synchromesh.


Yeah, i know guys run it with no probs, but I still wouldn't run it myself personally.

 

[hotrodnut]

I called Tremec and talked to John about this, he said do not use the Syncromesh because it swells the fiber material used in making the Synconizers in the 3650 transmission.

He said use Mercon III / Dexron III at a quanity of 3.0 to 3.2 ltr. I now use Motorcraft MERCON ATF #XT-2-QDX but I could not bring myself to lower the fluid level to what he suggested though but I did fill it to the 3.7L as specified in the '04 owners manual.

He said the specified fluid of Mercon Synthetic or any synthetic, is too slippery and there is not enough friction for the syncronizers riding against the dog rings to get them up to speed to match gear engagement. That is why the TSB for the early 3650's and the new '05 Manual states using Motorcraft MERCON ATF #XT-2-QDX fluid.

 

[the98stang]

mobil 1 synthetic ATF is the sh1t

 

[Pennywise2]

GM syncromesh will performance and work the best
in a T-3650 from what I hear.

 

[Marks5.0!]

mobil 1

 

[Stang|ess]

RP synchromax.

 

[Mustang5L5]

Does anyone here have any experience putting in a new fluid and finding it helping with shifting any?

What was Ford putting in the '03 3650? Was in synthetic then or were they still using conventional?

 

[hotrodnut]

Does anyone here have any experience putting in a new fluid and finding it helping with shifting any?

What was Ford putting in the '03 3650? Was in synthetic then or were they still using conventional?

I found the non-synthetic Mercon ATF #XT-2-QDX as specified for the '04-up 3650's, at the '04 specified fill of 3.7L, to help considerably. I have been using it for a couple years now and I have no issues.

Ford spec'd 3.8L (8 pints) of Synthetic Mercon ATF XT-2-QM for the '03 3650s.

 

[kevanp]

RP 3650 fluid

Dear KP,

We recommend the RP Synchromax for the manual transmission on the 07 Mustang GT.
Takes 3.15 quarts.

Cheers,

David

Royal Purple Inc
David Canitz
1 Royal Purple Lane
Porter, TX 77365
281.354.8600
281.354.7600 fax
713.725,7207 cell
[email protected]






--------------------------------------------------------------------------------
From: KP [mailto:[email protected]]
Sent: Saturday, August 23, 2008 4:26 PM
To: rpautotech
Cc: [email protected]
Subject: Automotive Questions


Which fluid is recommended for a 2007 Ford Mustang GT with the Tremec 3650 5sp Manual transmission. Manufacturer Spec Fluid= Mercon V

Thank You

 

[Superhereaux]

I ran Castrol Domestic Vehicle ATF, basically just regular old mercon/dexron III when i installed my MGW


Did help with the 2nd gear hesitation but not by much since it wasn't really THAT bad to begin with

 

[Mustang5L5]

Holy old thread.


I never ended up changing the fluid. The clunk went away slowly over time. I have 65K miles on the original fill and it shifts great with the MGW shifter.

If it ain't broke...don't fix it is what I always say

 

[poindexternasty]

If it ain't broke, do the proper preventive maintenance so that it doesn't break. I have had Royal Purple Synchromax in my 02 GT 2/ 3650 for a year now. 1-2 shift can be notchy at times, but my car has 99k miles on it on original tranny.

 

[SPEED DETAILS]

I am going to do a fluid change, I picked up some castrol Dex/merc domestic vehicle ATF. Its all I could find that was non-synthetic. Hopefully it works fine.

Castrol USA - DEX/MERC Domestic Multi-Vehicle

 

[comporange04GT]

I have had Royal Purple Synchromax in my 02 GT 2/ 3650 for a year now. 1-2 shift can be notchy at times, but my car has 99k miles on it on original tranny.

I have had the Royal Purple in mine for about 40K and have not noticed any notchy feel.

 

[spederman]

whats the recommended mileage change intervals for the T3650?