tranny and rear diff oil

[palmerc]

Have a 2000 7.3 and am upgrading the tranny pan and rear diff to the Mag HyTech...
What tranny oil would you guys recommend, brand and weight
What rear diff oil would you put in, same thing
thanks and the it is a limited slip

[MrJohnWayne]

tranny is Mercon SP. You could be amsoil synthetic. Hear some really good stuff about that.

rearend is 75W140 synthetic. Could go amsoil there too. I've used the royal purple that already has a friction modifier (which you'll need for the lim. slip) added into it and have not had problems.

[mschn99]

Originally Posted by palmerc

Have a 2000 7.3 and am upgrading the tranny pan and rear diff to the Mag HyTech...
What tranny oil would you guys recommend, brand and weight
What rear diff oil would you put in, same thing
thanks and the it is a limited slip

I wouldnt reccomend the Mag HyTech pan without first doing an additonal trans cooler. The extra fluid will take longer to get hot, but if it does get hot it will also be harder to cool down without the additional cooling....

The trans takes Mercon (Mercon 5 from ford, as their new formula is compatable with both fluids)

The rear diff takes synthetic 75-140 and you should add friction modifyer to it if the clutch packs for the limited slip chatter at all after the fluid change. That will clear the chatter up after a couple days if it does happen.

[mschn99]

Originally Posted by MrJohnWayne

tranny is Mercon SP.

Nope...only the torqshift trannies take Mercon SP.....Mercon or fords new Mercon 5 for all 4R100's......

[Lord Tauk]

Synthetic 75W-140 on the rear diff. Probably all the synthetics pretty much now have that friction additive for the springs in our LSDs, usually says on the lable.

Any Dexron III/Mercon trans fluid. The Mag Hytec Trans pan holds a lot more than the factory 4x4 pan, the diff cover holds more too.

FWIW, I just added the pan without going to a bigger cooler, temps haven't gone above 180 degrees in our summer weather, and it takes by my guess a normalish time to cool down, I even raced up at Cecil a few times a few weeks ago, no issues with it staying hot and not cooling down fast enough.

I'll get a bigger cooler sometime down the road.

[palmerc]

I thought the reason for getting the larger tranny pan was to keep the temps down, bigger better pan??????
I am adding the 4" exhaust this weekend with the EVO2 programmer and also changing out the pans of course......I was not told about having to have an auxillary cooler, I live in Reno, Nevada, gets hot here 90-100 in summer but only drive once a week with it, towing occasionally

what's the thoughts out there, anyone running these mods without the aux. cooler??
how much does the rear diff take to fill??

[mschn99]

The stock diff takes 3-3.5 quarts to fill......im guessing the new cover will add about half a quart so 4 quarts should do ya...

The bigger pad does add more fluid, and it does take longer for a larger amount of fluid to get hot. Problem is if the fluid does get hot, then it takes a long time to get it cooled down cause there is more there. I personally would get the larger cooler before putting the larger pan on myself...

[palmerc]

Well, the rear diff cover from Mag says to put in 6 quarts of the 75w 140 and it took it all plus 7oz. of friction......
Did the transmission change and I am having a hell of a time finding out if I have over filled the transmission fluid....maybe it is just me but the whole **** stick looks pink to me, cold or hot, maybe someone out there can tell me how to figure this one out