Synthetic vs. Conventional> What fluids do you guys use?

[DieselDaze]

I'm looking for comments and or advice on what fluids to use in my truck. I'm going to replace all the fluids from radiator to the rear axle. I'd like to know from users rather then a guide as to what weights and types of oils seem to work best. There are so many brands out there it seems its more marketing then performance to sway a persons decision. When looking for diesel motor oil does it have to be 'diesel' oil or just motor oil.

I've also heard of some using motor oil in the TC? is this true? And if so this is just what I'm talking about marketing, put plan motor oil in a pretty bottle and inflate the price 'because it must be good I paid a lot and its cool looking'. The ol addage 'sometimes less is more' applies more then not in life, especially for bass players.

 

[racinmike77]

yes sir 5w30 in the transfer case, ive been running it for 20000miles

75w90 synthetic for the differentials valvoline is good stuff maybe some locker additive from gm to help keep everything working smooth, transynd for the transmission and rotella for the motor, rotella comes in either 5w40 synthetic or 15w40 conventional both do an excellent job and cost only $10 a gallon.

 

[03 D-max]

i use Johndeere +50 in my motor and amsoil torque drive in my tranny

IMHO valvoline makes very good oils

 

[McRat]

The only area I'm not endorsing synthetics is the engine at this point. When I ran syn in Blue and Wendy, the oil pressure under high load was less. Our vette is the opposite. Casper doesn't get syn in the engine simply because the oil is changed too often. $$$.

 

[NelsonDiesel]

my LMM gets amsoil

my 02 gets delo


i do this because of the cost. I plan on keeping the lmm for a long time so the extra money in good oil is worth it in the long run. The 02 will blow up in due time and the money won't be wasted on helping extend the life of the engine.

I like synthetics but i do not agree with massive change intervals....

 

[NelsonDiesel]

diesel and gas oil are different.

engine oil in the transfercase is something that many are doing. I still go old fashioned and run trans fluid in there or i will step it up and run the blue stuff from gm.

if youa re looking into amsoil let me know. I can get it sent to you at my cost.

 

[Dzlnut]

John Deere Plus50 15/40 in the engine.

 

[coldLBZ]

I am running a 15w40 in the engine, Torque Drive in the trans, 75w90 in the diffs, and 5w30 in the T-case. All Amsoil synthetic. I don't agree with the long change intervals either, atleast not on my truck.

 

[whitetrash21]

What Pat said.... Hauling trailers around Vegas in mid summer with synthetics in can make oil pressure drop by 10-15lbs since it gets so hot. However the oil pressure is more consistent year round than it is with delo. I have delo in right now (same 15-40w) and the pressure will top 100 psi in the morning at 45*.... Once warmed up it idles at about 25 psi. That high psi @ cold temps is usually indicative of oil not doing what its supposed to be doing.... lubricating well. Thats why I dont put a load on it until it's warmed up....

rear diff has 75-90 Syn
trans has some form of synthetic (cant remember what now)
no transfercase and no front diff so.......

 

[03 D-max]

John Deere Plus50 15/40 in the engine.

WOW i thought i would be the only one :hug:

 

[TannerJP]

I swear by synthetics.
No huge feat, but we have an '01 cc lb dmax that we use to pull around 5th wheels, bounce around in the mud, run up an down the highway, etc. It's at 250k mi and it still out runs my '03 when the tuner is off. It gets 15k mi per change with filter every 5k and a top off (or sometimes not... it's dad's truck).

We sold a 1997 z-71 with 240k mi on it that we ran synthetics in from day one. It got no less than 10k miles per change. We did head gasket right before and the cross hatches were still on the bores; no ring grooves of any kind.

I've got 5-30w synt. in my t-case as well. So far so good.

I'm about to fill my trans with transynd. With Allison running thier fleet truck 200k miles per change, it's gotta be good stuff.

 

[LarryJewell]

I am running a 15w40 in the engine, Torque Drive in the trans, 75w90 in the diffs, and 5w30 in the T-case. All Amsoil synthetic. I don't agree with the long change intervals either, atleast not on my truck.

I changed to Amsoil in the motor and rear dif so far

 

[Dzlnut]

WOW i thought i would be the only one :hug:

I am a Tech for Deere so i get it at cost..the msds sheets say it is made by Shell or Chevron so you can't go wrong either way in my opinion.

 

[Noreaster]

Amsoil in everything
motor-10k change
tranny-torque drive-5k spinon, 25k internal
transfer case-5-30w-10k
differentials-75-90-100k

 

[DrededSS]

LB7:

Engine - 15w40 Schaeffers
Transmission - Full synthetic Schaeffers
Transfer Case - 5w30 synthetic Schaeffers
Rearend - Can't remember weight but also Schaeffers

I swear by that stuff since the fluid in everything except the engine still looks brand new.

LLY:

Engine - 15w40 Rotella with 1 bottle of GM EOS
Transmission - Schaeffers
Transfer Case - Standard 5w30
Rearend - 75/90 Valvoline

Poor dually doesn't get as much special treatment.

 

[E.carter]

John deere 15-40 plus 50 also....... The price is so good and its very easy to get even in bulk

 

[coldLBZ]

I changed to Amsoil in the motor and rear dif so far

How are you liking it so far? Are you running the AME 12 TBN 15w40? That's what I use.

 

[LarryJewell]

How are you liking it so far? Are you running the AME 12 TBN 15w40? That's what I use.

Whatever the marine/diesel heavy duty stuff is I like it, the motor seems a little quieter and what really impressed me was I can go pull the dipstick and the oil isn't black . I havent decided if I'm going to put Amsoil in the trans or not, I'll ask Mike L. when the time comes.

FWIW, i'm not doing extended oil changes, it will be every 5000 miles unless i'm giving it hell :angel: and then it would be a lot sooner than that.

 

[rainman4195]

Allison Trans - Pennzoil Dex III with No-Mo Friction additive
Engine - Mobil 1 15W-40 with No-Mo Friction additive
Front and Rear Differentials - Valvoline Syn 75W-90 with No-Mo Friction additive

I have not changed the transfercase yet because I was not sure what was the best thing to use. I would much rather find a GOOD alternative to the GM recommended fluid. If anyone has a good history with a better alternative, I would love to learn more!

Regarding the anti-friction additive, this stuff is GREAT! The only change I made other than fluid on my last service was adding the very small recommended amounts to each area and the MPG went up 2 MPG on average! In addition, the motor sounded smoother, and the trans shifter better. It is worth a look! The cool part is that you don't have to put the additive in everytime you change the fluids.

 

[Noreaster]

Whatever the marine/diesel heavy duty stuff is

Amsoil SAE 15W-40 Heavy-Duty Diesel and Marine Motor Oil