transmission fluid

[QIKSILVR]

What type should I use?  99 Chevy Silverado 5.3 anto trans.  Should I stick with the GM factory fluid or switch to another brand?  Synthetics...good or bad for transmission and transfer case?  Thanks guys.

[Black02Silverado]

Synthetics are always a better choice due to the fact that they out perform conventional oils. It depends on what you want to do with your vehicle. Do you plan on a lot of towing, or hauling or just plain run it hard? If so then synthetics are the way to go. Better protections under the stress of heat and better in the cold for fluid flow.

 

Now if you don't do much but normal driving and change your transmission fluid and flilter on a regular basis say every 25k. Then conventional ATF will work fine.

 

I can afford synthetic and it gives me a piece of mind to have it in the vehicle. I also like to do all my own maintenance so that saves me money also.

 

Stick with a good brand name fluid and you will be fine. You don't have to use specifically GM fluid.

 

Mobil 1, Redline, Schaffers,  and Amsoil are really good synthetics.

 

Hope this helped.

 

 

 

[QIKSILVR]

I heard somewhere down the line that synthetics in the transmission are "to slippery".  That it needs some friction modifiers of some sort.  Don't know if this is fact or fiction?  What type of synthetics are you useing?  I was looking at Redline.

[Black02Silverado]

Synthetic ATF is just fine for an automatic. I have had it in my 02 for a year now.  I know others in various makes and models, Mopar, Ford, Toyota that have it in theirs with no problems.

 

I run Amsoil's ATF. I flushed the entire system, 16 qts when I changed over to synthetic. That way I knew I had changed all the conventional fluid out and would get the full benefit of synthetic.

 

Redline is a good oil. I'm not that familiar with it. I would go to their web site  and get the proper part number of their fluid for your transmission.

 

[QIKSILVR]

If you had to choose between Redline and Mobil1, which would it be?  Is one superior than the other?

[CMNTMXR81]

Castrol TranSynd in the 2500HD

Redline ATF D4 Dexron III in the Z28's T-56

 

And anything name brand that's Dexron III ATF for everything else in the driveway.  I think currently I have Valvoline ATF Dexron III.

 

As to the synthetics, they'll work, but I've read numerous things about them not being good for a transmission.  In a manual, a full synthetic is a better choice than in a automatic as it helps shift smoothness and synchro operation.  Howver, generally, this is one of those cases where regular old ATF Dexron III will work fine.  As long as you provide normal routine maintanance and as an added bonus, periodically powerflushing the trans and converter, you'll be fine.  Regular (non-synthetic) fluid can go 50,000 miles in a passenger car or truck used similarly as a passenger car!

[americanmuscleman]

I'd recommend you not use a synthetic in your tranny.  I've used regular ATF in my trucks tranny since it was new with no problems.  I flush the tranny every 20k.  

 

I have synthetic in my camaro's 4L60-E, and when the synthetic was new, it shifted too soft (slower shifts).  I used to bark the 1-2 shift, and afterward, it would just slide through the shift.  After a few thousand miles, it got better, but its almost as if the synthetic is still too slick.  I added the synthetic to help reduce tranny temps and to help prolong the life of the tranny, which I think its doing, but my shifts aren't as firm as with regular ATF.  Not to mention, I also flushed my tranny with synthetic ATF and used almost 18qts of Mobil 1 ATF which cost over $100 in oil alone!  

 

I would recommend using regular ATF, and just flushing your tranny more often.  

[SilveradoWV]

I use a plain old Dextron III just like the manual says, and plan on changing the fluid and filter every 30,000 miles. I dont use any synthetics except gear oil and thats only because it was recommended by GM. For my purposes syn oil and tranny fluid is a waste, I am not saying syn's dont work, its just that I believe conventional oil and tranny fluid far surpass the needs of the engines and the tranny's for my purposes.

[clk7711]

[QIKSILVR]

Thanks for the info guys.  I have heard that in some cases that synthetics are too slippery.  I think I'll save my cash and just use the regular ATF.  ACDelco ok or do you recommend another brand?

[americanmuscleman]

AC Delco fluid should be fine.  Most ATF's are pretty much the same.  As long as you stick with one of the bigger manufacturers (Mobil One, Pennzoil, Quaker State, etc..), you'll be fine.  

 

The key to making a tranny last a long time is regular oil changes (and keeping the heat low).  

[ronbuick]

You can also use Ford's Mercon V, it is a synthetic blend and has the correct additives