If you’ve found this article, it’s probably because you have been searching for the correct kind of transmission fluid to put in your T5 transmission. First off, if you are not aware, you should know there are two types of T5 transmissions, the World Class, and the Non-World Class. The Non World Class T5 transmission came out first, in the early 80′s. World Class transmission came out later sometime in the mid to late 80′s, think of them as a ‘second version’ of the original Non World Class T5. Most internal parts are not interchangeable, and as such, neither are the fluid requirements. I won’t get into details on the differences of the two T5 transmissions or how to tell the difference, but there is a lot of information out there on that topic.
Now onto the point of this article – The type of transmission fluid you should use for your T5 transmission. Much like you, I was so confused as to what fluid I should use in my T5. There is so much mixed information out there, and everyone has their own opinions and own experiences. I don’t claim to be a professional transmission expert by any means, but I have now owned 3 of these transmissions, and have had varying degrees of problems related to different fluids.
My first T5 was a Non-World Class I bought from a junk yard, I was told to put in regular Automatic Transmission Fluid, which I did. After a few thousand miles I ended up destroying a main shaft bearing, and the output shaft was also damaged. At first I chalked this up to just being an old and worn transmission that was on it’s way out.
Instead of spending a ton of money to have it repaired, I decided to source out another used T5 transmission. After a month long search I was able to source out a World Class T5. Again I used Automatic Transmission fluid. The labels on the World Class transmission state to use Automatic Transmission Fluid, and most of the information I read on the internet state to use Automatic Transmission fluid as well. Again after a few thousand miles the transmission started making a funny noise, and it sounded much like my first Non World Class transmission did when it threw a bearing (or two). I never took this World Class transmission in to get diagnosed, so I don’t know the exact problem.
After destroying a second transmission, I decided to take the first Non-world Class T5 back to the shop that originally diagnosed the problem. Non World Class parts are cheaper than World class parts, and since this was going into an old 1963 Chevy C10 with an inline 6 I didn’t see the benefit of using the more expensive World Class T5. The transmission shop was unable to locate a new output shaft for it, and they told me in the long run it would probably be cheaper to just get a re-manufactured transmission.
I purchased my re-manufactured Non World Class T5 transmission, using my broken one as the core exchange. Speaking to the transmission repair guys, they told me that I should definitely be using Syncromesh fluid, which is what they use and what the re-manufactured of the transmission requires too. They told me using the new Dextron III type automatic transmission fluid might have been the cause of my bearings going out as well as the damage to the output shaft.
Since I have installed the new T5 in my truck, and filled it with 2.8 quarts of Syncromesh transmission fluid, I have not had any problems. I have to admit I have not put that many miles on it yet, and I will report back later if I do encounter any problems, but so far everything is running great and it shifts great too.
Now to be fair I can’t prove that using ATF in my Non World Class, and World Class transmission were the cause of the problems, after all they were used junk yard transmission and they may have been on their way out to begin with. However I trust the shop that diagnosed my problem, as well as the company that sold the re-manufactured transmission, they are providing a warranty after all and I’m sure they wouldn’t ask me to use a fluid that would cause damage they’d have to repair later.
A couple common questions that get asked quite commonly are below:
Q: How many quarts of transmission fluid to I use in my T5 transmission?
A: Both World Class and Non World Class take 2.8 quarts of fluid or oil. The general rule of thumb though is to fill the transmission up until it is completely full and fluid is coming back out of the fill hole.
Q: What type of Transmission fluid should I use in my World Class T5?
A: Truth is, I can’t answer this. The labels on the World Class T5 say to use Automatic Transmission fluid, however that was back when they made the Dextron II ATF. They no longer make it, and only make the new Dextron fluids. Newer Dextron III is suppose to be backwards compatible, so it should still work. I can tell you that I used Dextron III ATF, and I ended up with a damaged World Class transmission, as I stated in the article. Though I don’t know that the fluid was the cause of the damage. I would call a transmission shop or Tremec who took over the Borg and Warner line of transmissions to confirm the proper fluid.
Q: What type of Transmission fluid should I use in my Non World Class T5?
A: As I stated in my article, the transmission shop and company that re-manufactured my new Non World Class T5 told me to use Syncromesh fluid. This can be bought at any auto parts store. I currently am using the Pennzoil Syncromesh because it’s all that is available at the Advanced Auto near me. There are other brands too. DO NOT USE ANY TYPE OF AUTOMATIC TRANSMISSION FLUID!
Q: How can I tell the difference between the World Class T5 and the Non World Class T5 transmissions?
A: I recommend the following 2 websites to help you out:
And now just for fun, here is a photo of my re-manufactured World Class T5 transmission
My re-manufactured World Class T5 Transmission