What Transmision Fluid For My Tremec T-5?

Joey5.0

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Feb 13, 2006
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I just put in my new tremec T-5 and filled it with Valvoline ATF Dextron III/ Mercon, and it is leaking. Im wondering if i put the wrong stuff in....and why its leaking?
 
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is it leaking from where the driveshaft an the output shaft meet? and you can use that fluid or i have used
10w30 fully synthetic in my stock T-5 ...i think it shifts smoother an i have had no problems with it.
 
82rscapri said:
10w30 fully synthetic in my stock T-5 ...i think it shifts smoother an i have had no problems with it.

Onlt the early T-5's can run oil like that. The later 84-later T-5's NEED to run ATF. It's thin enough to reach inside and lubricate the needle bearings the gears ride on. Anything thicker will cause them to run dry and score and then whine
 
Joey5.0 said:
Well i just looked again and its leaking from the front....
The front of what?

Do you think it's coming from the bearing retainer mating to the trans?

Good luck.
 
fiveoho i have used 10w40 10w30 an 10w30 full synthetic...i find the full synthetic 10w30 makes it shift smoother. an when you shift fast you wont get that lil grind like you do with most stock t-5s with atf in them..this is from my own experience
 
from what i can remember, it should call for dexron-mercron 3. the ATF helps the blocker rings not stick to the input or output shafts, so you dont get a grind during shifts. synthetic fluid is definatly a good option though. as far as the leaking goes.. is the trans overfilled? that is somewhat of a common cause of leakage. dosent hurt to check as opposed to removing a trans. i think right about an inch below the fill plug is full.
 
WHen is it full? Right when it starts pooring out of the fill or right when it stops pooring out of the fill?

And can someone please confirm that i am using the right Tranny fluid?
 
82rscapri said:
fiveoho i have used 10w40 10w30 an 10w30 full synthetic...i find the full synthetic 10w30 makes it shift smoother. an when you shift fast you wont get that lil grind like you do with most stock t-5s with atf in them..this is from my own experience


thanks man :nice:

i think im going to try and return the other i got and go with the RP atf
 
89stangWhiz said:
wait, is this a stock T-5 or a Tremec tranny? They are not the same are they? I know that Tremec calls for GM Synthetic fluid, and its not cheap.


There is more than one Tremec transmission.


The T-5, t-45, t-56, t-3650, t-3550/TKO, t-6060


The one that most people think of when you say tremec is the 3550/TKO and is the ONLY one that takes GM synchromesh.

Everything else takes ATF
 
Tremec absorbed BW in the late 90's ('98 or '99) and so the same trans now had Tremec stamped on it.

The same fluid still exists. The synchromeshes are sometimes for some of the other Tremecs (I've seen people report its use in other trannies, like the 3000 series and 500/600's, etc. Check your specific application if using one of those).

Mercon is what I'd use for a WC T5. If you want a synthetic, I've used Redline D4. I wouldnt use motor oil or anything else when there are quality synthetic ATF's out there. If your BRAND NEW trans doesnt shift right with it, there's an issue. And if you used something else, there can be warranty (if applicable) concerns.

EDIT: Mike posted while I was typing.
Good luck.