AK4Dave

Just wondering how many of you have replaced all the fluids in the crank, diffs, and auto trans/trans case with synthetic oil....???

How do you like it....any improvements in performance?

If you don't like the idea....why?

After the -40 below cold snap we had up here I'm seriously considering it.

Thanks for your input...

09rubicon

I have gone all synth in mine (manual trans though). I did royal purple throughout. I think the biggest difference is piece of mind. Now I dont get cold snaps nearly as bad as yours, worst I have had is a week straight at about -2, but i did notice cold starts were a little better and my gas milage improved maybe 1-1.5mpg. Also a little easier to shift when cold (most of the shifting problems in manuals are the inner shift boot, not the trans itself).

pearl-drum-man

I've done the engine and the diffs, that's all for now. Would be a bit leary of messing with the tranny fluid (auto) other than the Mopar recommendations, but would have to really research that one.

Suffolk JK

From the first oil change...engine, transfer case, front and rear diffs. Transmission, going to in about 5k.

AK4Dave

So, what tranny do you have? I take it you've liked what you've seen/felt after the synth in the diffs and trans case enough to go for it in the tranny?

Like Pearl said, I have the auto and so far so good..........no problems. But I haven't ran it very hard either. I am just a little leary about using it in the trans seeing that I went ahead and paid the extra $2k for the 70k/7 year warranty. Would hate to change over and then have the damn thing explode or somethin'.
So that IS my main question I guess.......has anybody put synth in their auto trans?
Thanks....

falconfixer

Can't give you any advice (I got a manual and still use all conventional fluids) but after breakup we'll have to get some folks together and go wheelin'

RevyJKU08

I have placed all Synthetic not in the JK (YET) but in my 04 Dodge Ram CTD. I waited till about 100,000 km before I placed full Synthetic oil in my motor...I just wanted to be sure it was broke in.....as I talked with a few diesel mechanics and they mentioned somewhere between 50K to 75K km to break in the 5.9L Diesel motor.

The diffs in my 04 diesel already came with synthetic from factory but I replace every 50K km with royal purple. Also, I replaced my transfer case and auto tranny fluids with royal purple synthetic at about 50K km. The big difference I noticed with the auto tranny (48RE) -4 speed auto was it ran about 20 to 30F cooler from normal ATF. I can monitor the tranny temps on my Edge Juice Monitor. The tranny shifted much smoother and better with the Synthetic juice.

RevyJKU08

I have placed all Synthetic not in the JK (YET) but in my Dodge Ram CTD. I waited till about 100,000 km before I placed full Synthetic oil in my motor...I just wanted to be sure it was broke in.....as Italked with a few diesel mechanics and they mentioned somewhere between 50K to 75K km to break in the 5.9L Diesel.

The diffs in my 04 diesel already came with synthetic from factory but I replace every 50K km with royal purple. Also, I replaced my transfer case and auto tranny fluids with royal purple synthetic at about 50K km. The big difference I noticed with the auto tranny was it ran about 20 to 30F cooler from normal ATF. I can monitor the tranny temps on my Edge Juice Monitor. The tranny shifted much smoother and better with the Synthetic juice.

ronjenx

The JK auto requires ATF+4, which is synthetic.
Transfer case, too.

AK4Dave

Hmmmmm....I had no idea it was synthetic. Does it say this in the manual somewhere, or how did you learn of this?