For you guys who are running a synthetic tranny oil (Amsoil, Royal Purple, etc)....what intervals are you guys changing it? I'm currently running Amsoil in everything (engine, tranny, transfer case, and differentials)....I've got around 35k to 40k on the tranny fluid/filter.

I checked the fluid level the other day and it was fine. The oil also still looked decent. The weak link in all of this is the tranny filter and how long it can go till its not being sufficient...right?

Anyways...what are you guys doing?

 

All the tranny fluid for an auto is synthetic. I change mine every 20,000 miles, along with a new filter.

 

Engine oil every 10,000. Trans by/before 15,000. Diffs every 50,000

 

FYI, Mopar ATF is NOT 100% synthetic its made from group III crude oil. Mobil lost its lawsuit to Castro that in turned allowed group III oils to be called/labeled synthetic. The judge said the word synthetic is just a marketing term and why most oils and fluid sold in stores cost a lot less then group IV and group V oils & fluids from Redline, Amsoil and Royal Purple.

Amsoil web site states that its recommended for use up to 50,000 miles under severe service and up to 100,000 miles under normal service. I'll add if you race or drive in dusty and dirty environment you may need to change it sooner.

http://www.allpar.com/mopar/transmissions/fluids.html : The paper noted that one alternative was to use synthetic Group IV base stock, which are even more expensive than the ATF+4 solution, which provided Group IV style performance from Group III stock.

About oil groups:

Group II are the most common base oils in “dino juice,” with good performance in most areas except cold temperature viscosity.

Group III are called synthetic, and have high molecular uniformity and stability. Group III oil bases are used in most synthetic oils.

Group IV are chemically engineered stocks, arguably with the highest performance and longevity.

 

Pull a sample and send it in for testing.That will end any guessing and controversy.

 

Yeah, pretty much sums it up right there...I've never done an analysis on my tranny oil yet. Done several with engine oil...

 

Then you can come back on this same post and give us the results.Its been in my 1998 1500 in my sig. 54k(since about 40k and now 94500)and fliud looks good,shifts great and no torque convertor shudder on lockup which it did have before Amsoil installed.I used a BG Exchange machine way back when and swapped it out 100 percent.Haven't touched it since.

 

Well you are required to use an ATF-4 which is called synthetic aren't we?

 

ATF+4 is a group 3 which is highly refined but not a true synthetic.Amsoil and some others are a group 4 synthetic which is a top tier synthetic.The Amsoil is more then OK if you look at what its approved for.I've used it for hundred's of thousands of miles in Fords,GM and Chrysler vehicles.