going full synthetic

davig

Member
Jun 28, 2012
195
1
18
west jordan, utah
My truck just hit its 150, 000 mi. Mark. So am Planning on going full synthetic on all of my fluids. I tried gathering as much info from other posts and other peoples questions. But I just wanted your guys final opinion and make sure am not going to screw up my truck!

1st flush the system with essentialube
2nd putting amsoil synthetic 15w 40 in the motor
3rd amsoil synthetic 5w 30 in the t case
4th schaffers synthetic plus with molybdenum 75w 90 in the differentials.
And lastly putting allison approved transynd synthetic kit from the dmaxstore.

If there's any oil fluids missing or something I should be changing let me kno. Thanks
 

paint94979

Beer Nazi
Sep 18, 2006
11,715
8
38
37
I switched to Amsoil synthetic at 35,000 miles in my diffs, tcase, and engine. Maybe Amsoil is the reason my engine is alive still :joker:
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,685
5,840
113
Phoenix Az
brian is special.

ill be swapping my diffs back to full syn in a few months. ran reg crap when i was a tech cause i got it free. Currently motor has reg oil in it to get my rings to seat finally, trans uses dex III as mike told me to use that for a built trans over the transynd, t-case has 5w-30 full syn in it.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,685
5,840
113
Phoenix Az
no not for a stock trans. transynd will be better. the reason has to do with the clutches being harder for a built trans. mike would be better at answering the exact reason why though.
 

TLyons90

New member
Apr 22, 2013
1,631
0
0
Greenville, SC
I switched to Amsoil full syn when I bought my truck with 52,000 on her and she loves it! Eventually switching over everything to Amsoil and syn where I can!
 

Hot COCOAL

May the farce be with you
Jun 9, 2012
4,433
0
0
My truck also just hit the 150k mark, I just put royal purple 15-40 in the engine and it is running awesome! I have new gears, and after the break in I am using redline full synthetic, as it is the stuff on the shelf at Randy's ring and pinion, where I bought the Yukon gears, the guy who built my trans likes dex/merc 5 for fluid, and I am running the standard t-case fluid from the dealer, I thought it was synthetic???

I ran Mobil full syn 5-40 in the winter, and my truck didn't like it to well, at least I don't feel like it did, it seems to run better on 15-40, wether its syn or standard

Running synthetics won't hurt your rig, just make sure they are the proper weight and viscosity for each application:thumb: