Thread: What Tranny Fluid should I run?

The problem with such a survey is that people rarely can give you valid reasons for why they love/hate a particular fluid outside of things like "It worked for me", "I never had a problem", "Thats what so and so uses" and on and on.

I remember when I first got interested in this subject probably back in the very early 90's that I would ask people after they told me "This is all I ever use" why they say that. The blank stares were priceless.

Originally Posted by SyntheticShield

The problem with such a survey is that people rarely can give you valid reasons for why they love/hate a particular fluid outside of things like "It worked for me", "I never had a problem", "Thats what so and so uses" and on and on.

I remember when I first got interested in this subject probably back in the very early 90's that I would ask people after they told me "This is all I ever use" why they say that. The blank stares were priceless.

However to a lot of us as long as it works and creates no problems we are happy. I can respect both sides on this. If it works why waste precious time searching for the magic bullet. And believe me I certainly understand the flip side of us that can't leave good enough alone either.

Back in the day story. I bought a brand new 78 Honda Civic off of the showroom floor for $3200. I decided to take a trip to Virginia with my parents but take my car as well. Being intrigued by the Mobil 1 ads, I went to the Mobil service station and had Mobil 1 put in the right before the trip. 600 miles later we arrived at our destination. I guess at the age of 17 and investing what I considered a fortune for an oil change decided to check my oil to see how things were going. Opened the hood and the oil fill cap was gone. There wasn't a drop on the dipstick either. For years I was impressed that I never had a problem after that incident, especially driving though the appalachian mountains and how hard it was on the engine. Yet the Mobil 1 must have provided enough protection to keep the engine from seizing. I was a big believer for a long time...

Exactly. As long as there are no 'perceptible' problems, people assume its working. But just because you have no apparent issues doesnt mean it is working as it should nor is it the best for the application.

I mean I can put a 40 weight engine oil in the motor if I wanted. Will it work? Yeah and quite possibly for a long time. Is it the best thing that can go in? No. You may not see any 'perceptible' problems for quite some time but the added stress on the pumping system and such will take their toll.

Originally Posted by SyntheticShield

Exactly. As long as there are no 'perceptible' problems, people assume its working. But just because you have no apparent issues doesnt mean it is working as it should nor is it the best for the application.

I mean I can put a 40 weight engine oil in the motor if I wanted. Will it work? Yeah and quite possibly for a long time. Is it the best thing that can go in? No. You may not see any 'perceptible' problems for quite some time but the added stress on the pumping system and such will take their toll.

I suppose I should have mentioned using fluid or anything for that matter within the required specifications. I'm most impressed by the guys with more that 300K miles on their vehicles that have used the same thing with no lubrication related failures.

You guys have reminded me I need to address my tranny. Kinda scared. Its running 100% fine, but not sure if the previuos owners ever flushed it. I have 110k on it. Last FWD high mileage car I had flushed by Valvoline the tranny died 6 months later. I have heard good and bad about flushing high mile trannys. I dont know what to believe. Maybe a pan drop, new filter and max life fluid is my best bet? I did top it off with some Lucas about 30k ago.
On another note I also use full synthetic oil with the synthetic Lucas additive. I considered RP because of the speed channel's review. Gibbs racing has their own oil. I spoke with an engineer for Gibbs and he said it was designed for the Nextel cars. Wonder how that would be for our cars?

Originally Posted by archemedes

I hate those flushes when the pan is not dropped, there is a filter there, it's like draining your engine oil and leaving the old filter, not to mention you pull debris through the system (everyone I have ever talked to that had a trans flushed ended up with a new trans a few months later)

After my carnage, A good friend of mine managed a valvoline and said they started recomending against a flush on high mile engines because of the cars who had issues afterwards. My Z-34 had no tranny issues and I decided to have it flushed thinking it was a good idea. 6 months later I was stranded on an interstate 6 hours from home. The guy who replaced it told me stay away from flushes. Needless to say I have never done a flush since.
Like I said I think I should go the route of dropping the pan and replacing the filter. Then refilling with a high mile fluid like maxlife.

To address your statement a little. You can change your engine oil and leave the filter on and vice versa. But I would caution against it unless you use a filter that is extremely good and filters really well.

I have pulled HUNDREDS of oil filters apart and I can tell you the good high quality ones from the cheap ones without even seeing the name on the filter. I have seen high quality filters that are run for 15k+ miles and have pulled them apart and the element was still evenly spaced, pliable and in good condition.

I just serviced a vehicle not too long ago in which the person put only 1500 miles on the oil due to the fact he was running an engine cleaner and that was what the directions recommended. He brought it to me to service and we went through it front to rear (Jeep Cherokee). I pulled his filter off and cut it open for him and after 1500 miles the element was in horrible shape. The spacing between the pleats was horrendous, and the element was so brittle it just crumbled under slight pressure.

He also had me service his other vehicle that had the oil and filter on it for a year and nearly 10k. I cut open that filter right there in front of him and the element was still evenly spaced and very flexible, did not crumble at all.

So you can leave a filter on the oil system if it is a good one and you stay within the manufactures life cycle for the filter. But also keep in mind, you will most likely change your oil and oil filter more frequently than you do the tranny fluid and filter. So it is indeed more crucial there to change the filter with a transmission service or flush. Its a whole lot of extra work to have to drop the pan and change the filter, but it is well worth it.

I hardly ever do just a pan drop on transmissions and have never had any issues from that. I always prefer a pan drop, filter change and complete flush. In a regularly serviced transmission there should be no trouble with this process.

If you think about it, there is little difference between having the transmission flushed and doing a pan drop. If you do a pan drop and change the filter out and then flush it, there is no difference between the two.

A transmission shop simply hooks up a machine to the transmission lines and uses the transmissions own fluid pump to exchange the old fluid for new fluid. Even if the shop did not drop the pan, felt type filters (like the ones in our car) cant be back flushed. I had a hard time visualizing this until I pulled my own filter apart and its a two piece filter felt element that are sandwiched together. So debris gets trapped between the two pieces of felt and wont go back into the system.

Older screen type filters you could back flush because it was as its name implies, just a tight mesh screen. Debris got trapped on one side of it as opposed to in between the layers like the felt filters.

Originally Posted by SyntheticShield

If you think about it, there is little difference between having the transmission flushed and doing a pan drop. If you do a pan drop and change the filter out and then flush it, there is no difference between the two.

A transmission shop simply hooks up a machine to the transmission lines and uses the transmissions own fluid pump to exchange the old fluid for new fluid. Even if the shop did not drop the pan, felt type filters (like the ones in our car) cant be back flushed. I had a hard time visualizing this until I pulled my own filter apart and its a two piece filter felt element that are sandwiched together. So debris gets trapped between the two pieces of felt and wont go back into the system.

Older screen type filters you could back flush because it was as its name implies, just a tight mesh screen. Debris got trapped on one side of it as opposed to in between the layers like the felt filters.

The shop that replaced my tranny said the issue with the flush is the old fluid is removed and the new clean fuid is put in. It cleans the varnish and causes things to loosen that have seated over time. Then you end up with slippage and then failure. He said newer fluids have mild detergents and if you havent flushed regularily then its bad. 70K or so and its a first flush, not a good idea. I dont know how true this is, all I now is our trannys are expensive. 3 FWD cars later, a boatload of miles, 276k, 170k, and 130k, no flushes ,no issues Thats been my experience. Like I said I am by no means an expert, just my experience with it.

Tranny fluid doesnt not have the cleaning ability that some claim. Motor oil has better cleaning ability than does transmission fluid. And unless you run the fluid until its leather brown or something, I cannot see it building up varnish and what have you.

Trannyman would be one better to state this, but I have personally never seen a transmission with varnish build up. Now mind you Ive never broke down a tranny either but I have never seen it in the pan or in any components that reside in the pan. Whereas with motor oil you can see varnish build up over time in areas like the valve train.

Just my observations and opinion though.

Here are some pictures of my tranny cooler set up I took, when I had the motor out for my swap a few years ago.







Cheaper insurance than doing this...


Its a B&M super cooler I bought through Summit. I went to the local hard wear store and bought some 1/4" male to male brass fittings, and cut the factory rubber lines, inserted those into each one, then ran my stainless steel fuel lines to the cooler. The radiator holes that used to be used for the transmission heater, I plugged off using some brass plugs to keep stuff out of it.

This was installed in 2001, never a leak, never a hose blowing off like some see or hear about to this day. If you do the install right, and correctly, and use good quality parts, you should never have a problem.

Happy Driving!

~F~

And right on the GM Dex 6 bottle is recommended use in all Dex 3 applications

If you want to...

I have a few cases of III I need to use up first. I buy by the case at Sams, pretty cheap that way.

~F~

Originally Posted by 19SE92

yes it is and dex 6 is formulated for the newer trans's not the older ones like I have. Ive used dex 3 and i'm gonna stick with 3

Good luck finding it forever. They stopped making Dex III last year sometime. No more is being made...or will ever be made. Everything will be Dex VI from now on. The stuff you are able to buy is leftover stock. So if you want to stick with it, buy as much as you can now.

Read up here...

The big question is how prevalent Dexron-VI will become in the service fill market, which trumps factory fill volumes. The fluid will become GM’s recommendation for service fill on all cars and light trucks, although not in time for owners manuals of some model year 2006 vehicles. Moreover, the automaker is already recommending Dexron-VI for service fill in existing vehicles, noting its compatibility with transmissions built before model year 2006. To encourage the switch, the company will cease to issue Dexron-III(H) licenses at the end of 2005, meaning all such licenses will expire by the end of 2006.