So I know this is asked many times on different sites but here we go again. I have a 53 Chevy pick up that the T5 started not working well. So I took the T5 that I bought for my model A conversion that I am waiting so long to complete and put that in the pick up. The T5 I had in the pick ran ATF fluid. after doing too much research on the web seemed advisable to use synchromesh. So I put Valvoline synchromesh in the one that I just put in. It has a deeper fifth gear than the one that I took out. I believe it’s .76. It shifts fine, however, at a full stop. It is very difficult to put in the first year . Should I drain out the synchromesh and replace with ATF fluid? And if so, what would be the best fluid to use.
Like engine oil, which oil to use in a T-5 is the subject of much debate. From the original OEM manuals, you can see the following information: All NWC T-5 use 70WT Gear Oil or Redline MTL. ALL WC T-5 use ATF. ALL subsequent manuals tell us to use ATF in ALL T-5. So, what's the story? The OEMs originally used a 70WT gear oil in the early NWC transmissions. As the automakers were focusing on NVH and MPG, the switch to ATF was made and this coincided with the WC upgrade. It is generally safe to use in the early T-5 as well. However, do NOT use gear oil in a WC T-5 though - it will ruin the blocker rings/synchros. Use a quality synthetic oil (regardless of which type you need to use) & change it frequently (every 15-20K). Fill to the fill plug; about 5-1/2 pints or 2-1/2 quarts. Taken from this thread; https://www.jalopyjournal.com/forum/threads/tech-ultimate-t-5-article.171291/
So, Mojo, it’s safe to say I should drain the Sycromesh and add a quality ATF? Possibly my shift to first may be better?
I have two T-5 NWC behind bangers. I use Mobil 1 synthetic gear oil SC 75-90W. They have been happy They do not like to go into first gear if you are not to a full stop Had a buddy that was having problems with his S-10, T-5 going into gear and it wound up being clutch adjustment Can you get the transmission in and out of first gear with the car at rest and the engine not running?
That 75-90 is good in a warmer area and works good. My trans rebuilder who's done a couple 100 S10 T5's for me always puts a tag on every rebuilt trans recommending Dexron 3. Right or wrong we've had no failures so far. There is also a T5 fluid available from GM parts but I can't remember it's name. Most of you are not old enough to remember when the factory filled a bunch of the trans with the wrong fluid and they worked fine when it was warm but wouldn't shift when it got cold. Rather than drain, flush and refill the replaced them with new units. I found an enterprising parts man in a large dealer ship that rather than destroy the trans as ordered they found their way into his stash. I can't remember how many but I bought a large number of them, flushed them and resold them. The other way they were destroyed them was to break off an ear. There was another parts man that rat holed a large number of those and made a replacement ear and tig welded it back on. I bought quite a few of them and resold them.
Ran a NWC behind a flathead for years using Dexron ATF – zero issues with shifting and I drove it a LOT in all types of weather. (we get ALL the seasons here in the midwest)
The ONLY correct lubricant for a NWC T5 is 70W gear oil, and it has to be API-GL4, unless you can find 50W GL4. If you are using anything else, you are on borrowed time.
Have been running ATF in my T5s (5, both Ford and GM) for 30 years, both WC and NWC. Never had a problem and the synchros work perfectly. To the OP, you probably have a WC and definitely should be using ATF. Warren
Red Line 75-80 Manual transmission fluid. Non-world class T-5s use 70 weight fluid. Red Line has the correct properties.
If you've got issues getting in to first at a stop it's likely the clutch or the input shaft is dragging
The only T5s from S-10s that were WC began in 1993. Almost all of them were the ones with a Ford style bolt pattern on the front, except for the 1352-222 I had that was WC with a Chevrolet pattern. The Ford pattern S10 T5s used a hydraulic throwout bearing.
The first gear hard shift is the signature of an S-10 T-5. I had one, did everything under the sun but no results to get it to shift easier into first. I finally used some Royal Purple syncro fluid that helped a teeny bit, but that's all. Never cured it, sold the car but have a 700r4 sitting in the garage i was going to change out--it just drove me nuts trying to drive it in town. Almost everyone with the S-10 unit has the same problem.
If any consolation, the used (NWC, S-10 4 cyl version) that I put into my 52 Chevy Ute with a 235, has the same problem being hard to get into 1st gear. Doesn't matter if completely stopped or rolling. Slow rolling is better to get it into gear. Any other gears slip in and out just fine stopped or rolling. Many times I just give up and use 2nd gear to start. The 4 cyl version trans and 3.70 rear gear, with the 235 can pull it fine, just a little harder on the clutch slipping a tad more. I use the manual trans fluid in it.
Use ATF. Love the way it shifts into 1st gear. Have no idea what S10 trans it is just know I paid $225.00 for it from a friend.
I had a transmission business rebuilding T5 transmissions for nearly 30 years. I recommended ATF for all of them. I never had one come back that wasn't broken from abuse.
WC and NWC T5's are different enough in design that they may as well be two different transmissions all together. The absence of several bearings present in a WC T5 easily explain the different lubrication requirements of a NWC T5. Borg Warner was not guessing.
The use of ATF is to promote mileage to meet EPA requirements. I always use heavier synthetic. You need to go back to the old school method for shifting into first. Put it in second this stops the gears spinning and then go into first.
I had the first gear issue in my OT Thunderbird. A transmission rebuilder told me to put 1/2 bottle of Slick 50 in it. It solved the problem. I may have just been lucky, I don't know but it worked for me.
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