Engine/Transmission (1994 - 1998) Automatic transmission oil

[Kenr]

It's time for me to change my automatic tranney fluid again and the fluid I have been using (Castrol ATF+3) is no longer available in my area. Can someone point me in the right direction as far as what would be the best oil to use? I have used Amsoil Syn. in the past and after one of my many tranney rebuilding jobs a technician at BD told me that from his experience I should not be using this fluid. As of 9/26/01 I have done all the upgrades that I know of except the Kevlar clutch disks. The average fluid temp is 140 degrees to 165 degrees (200+) when backing up a steep grade (2 wheel drive in 4 low range engaged). I need to install a electric fan on one of my 2 tranney coolers.



Why only ATF+3 or 4? Why not Dextron3 Mercon; Aamco+3 is readily available but I don't know anyone who uses this product. By the way my truck is overloaded 90% of the time and is constantly pulling a trailer with a weight range of 4,000 lbs empty to 14,000 lbs loaded. Oil change intervals are every 7,000 to 8,000 miles. Any help would be greatly appreciated!

 

[Blakers]

I am running Dextron 3. The Aamco stuff is the same as ATF+3 and is available from AutoZone.



From what I was told, the ATF+3 is required only in certain Chrysler midget van transmissions to make them function properly. Rather than recommending a variety of fluids for different vehicles in their fleet, they just recommend the ATF+3 for everything. The Dextron 3 is fine for our transmissions and is about $1 per quart cheaper.



Blake

 

[SlyBones]

I am interested in why BD told you not to use amsoil. Many others including myself have been using it. I have been running it for over a year in my transmission. When first installed, I observed it does lower transmission temps too.

 

[Bob Wagner]

I agree with Slybones, Amsoil Universal ATF+4 works great

 

[BushWakr - RIP]

Bob, correct me if I'm wrong here but... .

The main difference between ATF +3 and +4 is this... the ATF +4 has more friction modifiers in it and will generally give you smoother/softer shifts. To do this the friction modifiers allow a bit of 'slippage' to occur thus creating a softer feeling shift.

The +4 has better heat properties due to the modifiers as well.

I'm running Dexron fluid in my system and it is a more "aggressive" fluid and firms your shifts up a bit.



Well, was I close???



BTW, I ran Amsoil in my stocker and had no problems with it AT ALL!



Bob.