Ever hear of running 5W-30 Mobil 1 in the transmission??

[OT-OF-HERE!!]

I've heard of this recently, and from a lubrication perspective it is suppose to be better,... also cooler running. Anyone hear or know of this. Just repeating what I was told by long time transmission guy.

 

[fox]

The trans-go shift kits recommend using it!!

 

[klenger]

What kind of transmission?

 

[Reb.B]

trans go used to recommend it, but i never see it any more. I believe they said up to 5-6 qts. I've had to put it in before, and never had a problem. With today's newly modified oils, i don't think it would be a good idea though. You lose your friction modifiers running less ATF.

 

[OT-OF-HERE!!]

I don't know for sure, but was told

A repair guy friend who has rebuilt many trannys tells me that ATF actually doesn't do that much in the way of lubrication and more with keeping things clean and that's why he thinks the Mobil 1 works good/better. Any real transmission guys know for sure????

 

[OT-OF-HERE!!]

what kind of transmission

What kind of transmission?

The transmission in question is the 48re.

 

[OT-OF-HERE!!]

Mobile 1 in transmission

I just talked with Joe Prince at Suncoast and he said no go on the Mobil 1 as it doesn't have friction modifiers in it suitable for the transmission.

 

[fox]

A reason to run something better than a 7-10 weight oil/fluid in a modern auto trans is to lube the overdrive section.

When in OD, a planetary is running and the fluid will thin when hot. I often wonder if the OD is getting the lube it needs.

Maybe adding a better lube-mobil 1 - might help things to last. Notice I said to add, as 100% might be too thick to work correctly in cold weather.

So, I wonder what might hurt things if 5 quarts are used in a total capacity of 12 quarts or with a deep pan 19 quarts. ?

I am not a oil/lube specialist.

But, I do know that oils are specially 'built' to each purpose. It is more than just dieing some oil red.

Detergents, lube modifiers, antifoamers are added in proven amounts.

I hope a trans guy gives us some comments.

 

[Nordby]

Using 5w-30 synthetic in the transmission is common for the Getrag 5spd used in the first gen's up to 1993. Overfilled by a quart as well. Maybe that is where this came from. My Getrag has 100K miles set up this way, about 160K total (dealer rebuild at 60K to try to fix a vibration, didn't fix it!)

jon

 

[BigGunZ]

I'm no transmission guy but I am a hydraulics guy. Personally I wouldn't do it. Modern ATF is actually hydraulic fluid and an auto transmission is essentially a self contained hydraulic system with unique lubrication needs. It would be far safer to run non-ATF4 fluid than to run motor oil.

 

[steved]

I know of guys around here running 100% 5w30 in 47REs without any issues... but (and I mean BUT) they are running modified trannies that were setup to run the 5w30... they are not a stock transmission... they have different clutches in them.



steved

 

[fzrace]

Bad idea. It's not the transmission clutches that you have to worry about, its the converter clutch that will have problems. To correct converter chatter problems, dodge came out with the +4 atf. It has friction modifiers specific for their trannsmissions. Best to not try to reinvent things thinking you are going to outsmart the manufacturer. Don't you think that if dodge could eliminate problems, they would use engine oil too?

 

[steved]

Bad idea. It's not the transmission clutches that you have to worry about, its the converter clutch that will have problems. To correct converter chatter problems, dodge came out with the +4 atf. It has friction modifiers specific for their trannsmissions. Best to not try to reinvent things thinking you are going to outsmart the manufacturer. Don't you think that if dodge could eliminate problems, they would use engine oil too?

The clutches aren't the only thing that's modified in these trannies... I know they are running 5w30 without any problems... with well over 50k on the rebuild (several years ago)... if I had know about it sooner, I would have had the 47RE in my 99 rebuilt the same way...



Just because dodge designed it one way, doesn't mean the aftermarket hasn't compensated for it... and ATF+X was originally designed for the dodge [mitubishi-based] cars, not the trucks. They run it in the trucks as a matter of convenience. I ran straight dexronIII in my 99's 47RE for well over two years and 80k miles with not one ill effect from it... as far as I know the guy is still driving it that way today. If you think about it, even the 47RE isn't too far off from the old 727 in many ways. The shop that built my 47RE told me that ATF+X causes seals to harden and leak... what they say was the leading cause of failure in the dodge cars/trucks.



Just food for thought,



steved

 

[Dieselnerd]

I used to run about 3 quarts of Mobil 1 5W-30 in my Goerend modified 47RE. This was on the advice of Dave Goerend who modified the transmission. The reason was to lubricate the OD gears better when towing heavy. I put a lot of miles on that transmission before I sold the truck, always towed in OD, and it was working as good as new when sold. I haven't added any to my 48RE and don't plan to since my current truck is rated to tow my trailer weight with plenty to spare. The old truck wasn't which is why I had the transmission modified after I burned up the TC Clutch.

 

[fzrace]

In my 95' I switched to dexron type atf. I had converter shuddering as a result. I did'nt know about the chrysler spec oil at the time. When I swithced back, the problem went away. Go figure.



I have rebuilt the transmission in my 95' enough times that from my expierience, the planetaries seem to go bad from to much thrust clearance, eventually causing gauling on the thrust surface of the planet.



I just don't see engine oil as the silver bullet to fix or prevent transmission problems. Problems tend to go a little deeper.



If your going to use engine oil in your transmission, why not use true motorcycle oil. Cycle oil has lots of zinc in it, which plain bearings love, and a fair amount of EP additives. They use the EP additives because most motorcycle oil does double duty dealing with the transmissions that are part of the engine. It also doesn't typically have friction modifier in it as that makes motorcycle wet clutches slip.

 

[BigGunZ]

I think a proper rebuild can overcome the friction problems with the TC clutch. My biggest concern would be how the numerous small orifices within the transmission, will react to a multi-viscosity oil considering that many small passages are calibrated to achieve a certain flow rate, and certain valves need to operate at a certain speed. All that said, I can easily believe that a properly built transmission can be confingured to accept motor oil... but a stock transmission would likely not feel right.

A modern aircraft turbo-prop engine shares it's synthetic engine oil with a gearbox that can easily have to absorb up to 6000 shaft horsepower. In fact, Mobil Synthetic Jet Oil led to the developement of synthetics for automotive applications... it does work in trannies.

Motorcycles are another shining example of engine oil being shared by the transmission... and MC trannies have wet clutches as well.

 

[keimmmo]

I add one quart of 5W-30 full synthetic motor oil to the Dexron III ATF at every change on both my trucks. Have been doing so for over 100k on the 01. 5. Have been doing so for about the same on the 92... with a total of 330k on the truck. Neither one have ever had trans problems!



Steve Keim

 

[OT-OF-HERE!!]

5w-30

I add one quart of 5W-30 full synthetic motor oil to the Dexron III ATF at every change on both my trucks. Have been doing so for over 100k on the 01. 5. Have been doing so for about the same on the 92 ... with a total of 330k on the truck. Neither one have ever had trans problems!



Steve Keim

Steve,



You add the 5W-30 because,... ..... I'm looking for why some add 5W-30 in whole or in part and why they are doing it,... with the facts pls. Tks.

 

[BigGunZ]

Steve,

You add the 5W-30 because,... ..... I'm looking for why some add 5W-30 in whole or in part and why they are doing it,... with the facts pls. Tks.

Just guessing but the engine oil is likely a better lubricant.

 

[keimmmo]

Yes, for better lubrication... and it makes the trans shift better. Straight Dexron III shifts a lot firmer than ATF+4. A little 5W-30 synthetic makes it shift more like original. I have READ that it also helps keep the seals soft. Anyway, 100k miles on the mix and NO problems.



In the 01. 5 I also changed the lube in the transfer case from ATF+4 to 5W-30 full synthetic. I am told it is about the same weight as ATF. In the transfer case friction modifiers ARE NOT an issue... lubrication is! It also makes it shift really nice!



Steve Keim