Is synthetic fluid in transmission's better than regular transmission fluid.

Jeff

in general there are many (myself included) that believe Synthetic is better. You weren't real specific in your question tho regarding what type of vehicle you have, or type of tranny. Heat is what will kill an auto. tranny faster then just about anything else. Heat breaks down the fluid. synthetic can take much more heat before it starts to break down. so in theory synthetic can take more heat than fossil fluid. I believe that is true so I use synthetic wherever I can.

Having said that, you need to look into making sure the synthetic is a compatible replacement for the fossil fluid. The Allison that GM uses has Trans-synd (think that is what they call it) that is a synthetic. But it is made by Allison and they have not release the formula for anyone else to manufacture it. So your really limited to using their fluid. AMSOIL reverse engineered it and sell it in their product line if that is any consolation.

In the case of the `05 and `06 Fords (effects me) there is no other brand to go with except Ford's fluid.

using anything else but a compatible replacement will void your tranny warranty.

Short answer is yes. It tolerates heat better. Main thing is use the correct type for your transmission as specified by your owners manual, regardless of whether it is dino or synthetic.

My transmission (Ford 4R100) requires MERCON and the owners manual states do not use MERCON V. Mobil 1 ATF (a good synthetic) used to be MERCON but is now MERCON/MERCON V. so I dont use it. I use Royal Purple Max ATF synthetic (a MERCON labeled fluid). Synthetic ATF runs $7 or more per quart and I needed five gallons. Considering a new transmission would cost me over $4000, spending around $150 on fluid was worth it. If you are towing, adding a transmission cooler like a "Tru-Cool Max" and a transmission temperature gauge is worth it too. If you have a ford with a factory dash trans temperature gauge, those are no more than idiot lights that only go to "hot" way too late to save your tranny.

Two Bit is telling you straight. My study on synthetic oil indicates use of it will allow a full 100 degrees F higher temperature before breaking down. It produces no varnish as it ages and that in its-self is worth the extra money. The longer you let the oil go without changing it, the more important it is that you use synthetic. Its a lot more money but I feel its worth every penny of it.
Jim

bob is the oil guy
read here it has everything and then some you ever thought about wanting to know or forget about lubricants

Dodge

Not sure if ATF+4 is a full synthetic, but I recently purchased and installed a case of the stuff (Vavoline from a NAPA Store, much less expensive than the MOPAR ATF+4) in a '96 Dodge gasser with 130K miles. No problems making a 360 traveling from Boise to Sacremento, through Yosemite even though tranny temps approached 300 deg F. for short periods. (the tranny temp sensor is mounted between the torque converter output and the radiator cooler).

Dodge transmission TSB's
http://dodgeram.info/tsb/2004/21-004-04.htm

ATF+4 News
http://ilma.enewsletterpress.com/news/default.aspx?IID=63

New to the forum.

Just installed myself a Banks Powerpack, Ottomind, transcommand on 2004 Damon Instruder with V-10. Live in Colorado and pull ATV trailer weighing about 3500#.

First trip to nearby ATV location and system worked well particularly the shift points. However, at highway speeds when downshift was needed it works well but on the upshift under acceleration, there was a very brief high pitched noise just before the upshift. Don't know if that is the tranny slipping. Only have 11,000 miles so I'm going to check with banks. May switch to the royal purple but the change out sounds a little complicated.

thoughts?

Read this thread entitled synthetic oil-isn't, before making a desicion. Read all the linked documentation of the article to confirm the authors veracity.

I held off going to synthetic and decided to switch this spring at my mechanic's recommendation with 82,000 miles on the truck. Only one camping trip this year so far, but I can see the trans is running 20 degrees cooler when towing. I also think it shifts a little crisper, especially at higher RPMs (2500-3500).

Change was done with both a pan drop and filter change, followed by a machine flush to get the rest of the dino out and replace with synthetic.

I had been cahnging fluid every spring since the truck was new, but may let the synthetic go two years, we'll see how it performs this summer.

Still running dino oil in the motor, change with the filter every 3K miles.

How about Royal Purple or Mobil 1 in a Ford C6 behind a Ford 7.5L?

I know factory fill in many sumps and crankcases now are synthetic, and an Amsoil rep told me that military jets have been using synthetics for years.
I switched the 7.5L Ford engine to synthetic, and it made a HUGE difference in the temperature increase when climbing the same grade out of the Columbia River Gorge. Synthetic Blend = over 30 degrees. Full synthetic = maybe 4 or 5 degrees!

With that visual proof of what I have been hearing for years, that synthetic dissapates heat faster than fossil, and knowing that HEAT is what kills auto trannies, can anyone tell me why I should NOT switch my C6 to full synthetic? Would like to avoid any little "OOPS" that anyone might know of, peculiar to that particular changeout.

Thanks in advance,
Ken