It cool that we have an oil forum. I ended up with 3 gallons of valvoline full synthetic 75w-90 for almost free so plan to run that in my diffs (d60 & 14 bolt with air lockers) and transfer case. So the question is how often should a person change out synthetic gear oil? In previous vehicles I always ran sta-lube and never changed it. But I've got a heck of a lot more money in this new rig and plan to keep it until I die so want to keep things tip top.
NP205
- Thread starter RMScout
- Start date
Oh, and out of curiosity how do gear driven transfer cases do with atf in them? I've read many times that GM specified atf for a while in np205s. Supposedly for fuel mileage. I've never taken one apart that had been running atf so have no first hand experience but would guess they wouldn't last as long.
DF Sales&Marketing
Oil Tech Moderator
Rmscout:
GM has recommended atf, or a type of atf for transfer cases for some time, and it seems to be working ok in them. I'm not sure if there is a different design or what it might be, but atf, especially the ones made for standard automotive use, including the dexron (a GM variety) do not include very much ep additives. The swepco 714-20 atf, however has a huge amount of ep additives in it, and many people have used it in the transfer cases, however if the case calls for a gear oil type lubricant, you should use gear oil, and our first recommendation would be the 210-80w140, which you can also use in the manual transmission and the differential thus utilizing the "k.I.s.s." principle.
I will not comment on how long the valvoline can be run without changing as it is not a swepco product, but providing it does not get contaminated with dirt or water, the two killers of gear oil, especially in differentials, it will probably be ok for awhile with regular checking....just make sure you didn't just get your monies worth!
Dick floryanowich
df sales & marketing
GM has recommended atf, or a type of atf for transfer cases for some time, and it seems to be working ok in them. I'm not sure if there is a different design or what it might be, but atf, especially the ones made for standard automotive use, including the dexron (a GM variety) do not include very much ep additives. The swepco 714-20 atf, however has a huge amount of ep additives in it, and many people have used it in the transfer cases, however if the case calls for a gear oil type lubricant, you should use gear oil, and our first recommendation would be the 210-80w140, which you can also use in the manual transmission and the differential thus utilizing the "k.I.s.s." principle.
I will not comment on how long the valvoline can be run without changing as it is not a swepco product, but providing it does not get contaminated with dirt or water, the two killers of gear oil, especially in differentials, it will probably be ok for awhile with regular checking....just make sure you didn't just get your monies worth!
Dick floryanowich
df sales & marketing
All versions of the 205 are basically the same as far as gears and bearings, with the exception of the syncro versions. However, from what I've read atf was specified on some NP205 vehicles both with and without syncros. Originally they called for gear oil, but GM changed the spec in about 1980 without changing anything inside the transfer case. Your 80w140 sounds good, but I'm going to stick with the full synthetic.
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Craig
Active member
Yes and those same GM engineers took a Chevy 350 and converted it to diesel. I.e. Not the best engineering move.
The engineers were willing to state the t/c could last past the warranty period running on atf in a quest for mileage.
I would run what the original engineer that built the t/c said to use. Gear oil!
The engineers were willing to state the t/c could last past the warranty period running on atf in a quest for mileage.
I would run what the original engineer that built the t/c said to use. Gear oil!
Thanks for the thoughts. I was of the same mind but after doing some research all I found was a bunch of guys on the Chevy forums saying they had ran atf for years, some since new, and never had any issues. A couple of guys had disassembled 205s that had been running atf said they looked like new. It still seems like gear oil would be better, but it's hard to argue with proven long term results. Especially when there are other benefits. Better gas mileage and better cold shifting. Not to mention all the manufacturers that have used atf in gear driven boxes.
FDChappie
Well-known member
I've run mobil 1 15-50 in my d-20 for about 15 years now. It's not any more worn out than when I started using it. This unit has seen a lot of hard use too as I used to live on a 1.5 mile dirt road with a 1000' long 23% grade.
In the spirit of complete disclosure I also ran the same oil in the t-18 on the Scout and it is now worn out. The darn thing only lasted about 400k mi. Even when built like the used to they don't last forever. That tranny was pretty worn at the start if the mobil1 trial. I do plan to change the mineral oil now in the replacement t-19 in the near future.
In the spirit of complete disclosure I also ran the same oil in the t-18 on the Scout and it is now worn out. The darn thing only lasted about 400k mi. Even when built like the used to they don't last forever. That tranny was pretty worn at the start if the mobil1 trial. I do plan to change the mineral oil now in the replacement t-19 in the near future.