seabiscuit

Can anyone give me a link to some good Manual Transmition Fluid for Mustang GT or at lest name and brand, reference code. What color it should be? I was thinking that it is Dexron III ATF with Mercon spec - so Red one. But when I check the level it is clear one so what is that?

Embalmer

I've been using Royal Purple Synchromax in my manual trans for a couple thousand miles and I noticed an improvement in shift feel and MPG. I also changed my rear gear lube at the same time to the Royal Purple stuff. I get 23.6 MPG now and before I got 22.5.

seabiscuit

By the Rear Gear you mean you changed for that one: Max Gear 75w-140? http://www.royalpurple.com/gear-oil.html

Embalmer

Yes, that's what I used.

seabiscuit

Ok last question about Rear Gear Oil. Did you add to that some Friction Modifier XL-3 - 4oz. as the Mustang guide suggest or Royal Purple Max Gear do not need that?

Thanks a lot for your help.

jasongt06

I put Motorcraft Mercon V in my manual 07 GT and it shifts very smooth.

Bullitt995

Redline everything is the best money can buy as far as fluids go.

Embalmer

Friction modifier isn't necessary. It's included in the fluid already.

ronslakie

I have used Redline in my other vehicles (manual transmission, differential and transfer case) and the results have been excellent.

metroplex

I use Redline High Temp ATF in my 07's TR-3650. For the rear-axle, I am using the factory-fill gear oil in the Stang. In the other Fords, I always use Redline gear oils.

gkaufman

I changed my transmission and differential fluid 2 weeks ago. I used 3qts of Royal Purple Synchromax for the tranny. 2qts of Royal Purple Max-Gear 75w140 + XL-3 in the diff. I had heard issues with just relying on the friction modifier built into the gear oil so I added the 4oz XL-3 to the mix just in case. I think my mileage went up slightly .. hard to say. There was a huge difference in the way the shifter goes through the transmission now. Really great stuff.

seabiscuit

Can you explain more why you add XL3 Ford modifier if Roayal Purple Max Gear is already modified with Synerlec technology?

BTW what you think about that KENDALL Modifier? Did any one heard about that?

http://cgi.ebay.com/ebaymotors/Posi-...mZ320259885179

SeanD

How hard/easy is it to change the transmission oil? I heard that there is no drain plug on it, is this true?

gkaufman

I researched and found that some people had noise in the rearend on tight turns after adding just RP. After adding a 4oz bottle of XL-3 the noise went away. I decided to add the bottle anyways so I didnt have to revisit it again. I really dont think there is any harm done by adding the XL-3 to the mix. It locks hard on launches and no longer groans on tight turns. All with 68k miles.

There is a drain plug on the bottom of the tranny. You simply slip a 3/8 ratchet on it and take it off. Be sure to open the fill plug first. It is located on the passenger side about 4 inches up. The fill plug and drain plug are the same type of plug. Opening the fill plug first will prevent the fluid from "glopping" out with lots of force. Thus splashing eyes and floor around the drain pan.

You need thread sealant and Loctite for the plugs. I added the 3qts back in via a hose run down the shifter hole into the fill hole of the tranny. Granted it's a little scary squeezing a bottle of Synchromax into a hose(3ft should do it) inside your interior. Just be careful. The level of the fluid should be 1/2 inch below the fill hole. I used a small allen wrench to place in the fill hole and measure with. Be careful not to drop the wrench in . 3 quarts of Synchromax was exactly the right amount for me. I did have a 4th bottle just in case.

Its rather easy to change the tranny, the differential is another story. It's easy as well but requires more time to clean the inside out and remove all the old RTV. The effort put in here pays off by not having any leaks.

wjones14

Mobil 1 Synthetic ATF is another alternative. Synthetics are always better than non-synthetics in oil and transmission fluid. http://www.mobiloil.com/USA-English/...hetic_ATF.aspx

RadBOSS

Adding more friction modified to an oil already formulated for a posi is probably overkill and may even be detrimental to the differential clutch pack . More is not always better, other wise they would recommend putting in 2 or 3 bottles of that stuff.

This trans does have a drain and fill plug (see attached).

seabiscuit

We know the trans have fill and drain plug but rear differential do not have.

gkaufman

Doubtful. The only "detrimental" thing would be that the posi doesnt lock as hard. Which isnt true either since it seems as though its locking harder now after my fluid change.

seabiscuit

Ordered today Roayal Purple set of oils for trany, differential and for engine as well - lets see if that is really such good oil as everybody says.
Thanks all for help. Of course I will and XL-3 to rear differential friction modifier as well.

RadBOSS

That was message was for SeanD's benefit, not you. I posted the shop manual pages so he would know where to look. Some people don't know what to look for manual trans drain and fill plug.