Trans fluid - Synthetic or not? Need advice

[tschwab]

40k miles on truck, have used +3 up to this point, considering going to synthetic next full change (torque converter & pan) holds about 18 qts.



Main reason for considering synthetic, is to run the lowest possible trans temps when towing, which sometimes can hit about 220-240. How much cooler would synthetics run?



Thanks - Terry

 

[Howard Durand]

I don't think synthetics run any cooler but they will withstand higher temperatures without breaking down.

If you need more cooling, an aftermarket cooler with fan would be more appropriate.

 

[Jetpilot]

What Howard said... ...



Doug

 

[Dane]

Whatever you use, don't forget to change it every 30K miles, more often if you tow/haul.

 

[Extreme1]

These transmissions do produce a lot of heat, especially in city traffic when towing. With the TC locked up and on the highway mine runs a little over 140 (sensor in the line out of the trans).



220-240 is "normal" when it's working. I use Amsoil. Check your owners manual for trans fluid change intervals. Mine is 15,000 miles and I stay pretty close to that.

 

[tschwab]

Thanks for the replies so far. Don't get me wrong, I have changed the fluid every 10k miles since the truck was brand new. What I would like to know... . everything being equal, will a transmission full of 100% synthetic run any cooler vs a transmission full of regular Mopar ATF +3?



And if so, what does synthetic approx cost per quart/gallon? Thanks.

 

[rrausch]

Mine came with Amsoil when I bought the truck used with 57,000 on it. I now have 138,000 on it. The truck came with gauges. I didn't see any temp difference when I changed to +3.



edit: Sorry I didn't realize this thread had been started by a guy with a DTT trans.

I just deleted the part about my Perf. Trans.

 

[Bob Wagner]

how in the heck can a tighter convertor equal lower temperatures?







sounds like _________

 

[Bob Wagner]

Originally posted by rrausch





I didn't see any temp difference when I changed to +3. However I did see quite a bit of difference when I got a Perf. Trans from ATS. It hardly ever goes above the 140 mark, even in heavy stop and go traffic. I was surprised at this development, as no one had told me the ATS TC would affect trans temp. , but it does keep it lower.

where is your sender located?

 

[amsoilman]

tschwab,

A true PAO based synthetic ATF will indeed run cooler, as much as 25-30 Deg F. This is due to the moleculer uniformity of the oil. All of the molecules in this type synthetic are of the same size,shape and form.



Wayne

amsoilman

 

[Diesel Gunner]

In addition, a full synthetics have higher oxidation stability. Heat, which increases oxidation rate, and shear are the two greatest contributors to ATF degradation.



Any full synthetic will outperform a conventional ATF in this arena. I use synthetic ATF in my Lincoln Mark VIII and I can tell you that the transmission is quiter and shifts better than when it is filled with a conventional ATF. Does it run cooler? I don't know as I don't have a temp gauge on it. I would think that it does because of the superior properties of synthetic ATF. Is it worh it? That you have to decide for yourself. It costs me in the neighborhood of 100$ to do it myself every 30K. It is still cheaper than having it in the shop.

 

[Bob Wagner]

terry, amsoil universal atf +4 is 5. 86/qt in NE Auburn. I've been running it since DTT upgrades going on 3 years.



Both products work 100%



(no I am not an amsoil dealer)

 

[Elite1]

a "true" synthetic=less friction=less heat

 

[78repowerwagon]

Originally posted by Bob Wagner

how in the heck can a tighter convertor equal lower temperatures?







sounds like _________

A tighter converter does not work the fluid as much, so temps are lower.

 

[Bob Wagner]

Originally posted by 78repowerwagon

A tighter converter does not work the fluid as much, so temps are lower.

a tight convertor if done right right is ready to "rock n roll" as soon as put in D



what convertor are you running?

 

[Blackcloud]

Terry-I think alot of it depends on how hard you are on your truck and how much actual heavy towing you do. I look at synthetic like this,it costs roughly 3-4 times as much as regular ATF and if you are doing changes as often as you say you do,then I feel it is not worth the extra cost. I have and do use synthetic and feel there is a place for it. Your individual use should determine if you "need" it.