A friend of mine recently had a Luxus mechanic suggest to him that he add a qt of tranny fluid to his crankcase just before his next oil change to clean it out. The Luxus had 130K miles on it.

Anyone every try this on an Isuzu? I know tranny fluid is high in detergents and is basically 20W oil. Thoughts?

Don't do it! If you want to de-sludged your motor I suggest you drop the pan, clean the pickup screen and oil filter mount passages. It's a dirty job but, someones gotta do it... I'm sure once you put that stuff in there you'll never get it all out and your just going to ruin the viscosity of your new oil.

Bologna!



Running a quart of automatic transmission fluid just before an oil change will not hurt a single thing. Yes, it will work to help cut some varnish out and keep things nice and clean inside. People have been doing this for years and I do it myself. It works just as well as any "engine cleaner" additive that you buy off the shelf.
Just before you change your oil (30 miles or so) add a quart of tranny fluid (just don't over fill the crankcase... drain a little out if you need too) and go drive it for a while... Once you add the tranny fluid in, I recommend changing it out as soon as you've driven it some (without shutting down..) By that, I don't mean don't shut the engine down.. I mean don't wait 3 days later to change it. Go out and run it for an hour or so and then come back and change it... Be sure to change the filter as well... and you won't have a bit of problem.

No thank you! <img src="/forums/images/graemlins/shame.gif" alt="" />

I guess if it works for you that's great. <img src="/forums/images/graemlins/kewl.gif" alt="" /> I wouldn't do it and that's my 2 pennies...

Well, if you don't want to do it, that's fine. But you shouldn't be giving people false information that it will ruin the viscosity of the new oil. That is completely false. It will not ruin anything. People have been using transmission fluid to clean out engines for years.

This is with auto tranny fluid, right?

Yes, this is common. I dont normally do it on many engines... BUT...it WILL NOT hurt anything....

Anytime we find a car that has been sitting(like those beautifull 60s era cars that have been sitting in a barn for 15 years), we drop the oil and filter, replace with one qt fo Dexron, adn the rest with a nice this oil..0-30, or 5-30, than a few ounces down the intake, rotate by hand, abot 3 revalutions, adn let it sit for a few days...

Come back, fire it off, let it get warm, and let it run for about 20-30 minutes... then drian the crankcase adn replace the oil, fileter, adn plugs....

Has worked so far....

Anyway, ATF has tons of detergents, adn friction additves(only work with certain materials IIRC), so, thats why some people recommend it... especially on a high mileage engine, to get the "sludge" and other crap out....

Chase

Calm down TIGER <img src="/forums/images/graemlins/zombie.gif" alt="" /> that's what the wire is all about! <img src="/forums/images/graemlins/notooth.gif" alt="" /> If i'm wrong then I'm wrong you don't have to take my advice, the subject will be discussed <img src="/forums/images/graemlins/mrt.gif" alt="" />
Like I said I wouldn't do it and if I recall the question was .Tranny fluid has very little friction additives(otherwise the clutch plates get burnt and slips!). Now why would I substitute 1qt of friction additives found in engine oil for low friction stuff just to clean the crap out! I feel there may be a better chance of bearing/metal to metal damage.

I think the key is to run it briefly with the AT fluid, then change the oil/filter immediately. It's not something you want to leave in there for any extended period...

First off, if you have proper oil pressure you aren't going to have bearing to metal contact... As such things with a crankshaft, rods, and cam... all ride on a film of oil and don't have a metal to metal contact except for initial start up... in which it doesn't matter what oil you run, unless you have a pre-oiler, you run the inital split second dry, until oil pressure is built up.

And just an FYI, do you realize that motorcycles have wet clutch systems, very similar to that of an automatic transmission? Have you ever looked at the recommened oil for a motorcycle? It doesn't contain the 'friction additives' that you are talking about. Why? Because it will cause the clutch pack to slip... Doesn't seem to hurt motorcycle engines... which last time I checked, still use crankshafts, cams, and rod bearings.

It's also funny how mechanics have been using transmission fluid as a cleaning agent in engines for the last 50 years and it's never hurt anything before. Like I said, if you don't want to use it fine... but don't give other people false information about it ruining your engine or your oil viscosity. Viscosity is the 'thickness' of the oil. It's measured by determining how much fluid (oil) will flow through a given orafice in a given period of time. Now, if you add a quart of 20wt tranny fluid to 20wt motor oil, how do you figure the viscosity is going to change. This has absolutely nothing to do with the friction additives that you are now talking about, which you didn't mention in your first post... you said it will ruin the viscosity.

And as BigSwede stated:


That was pretty much the advice given above.