another favorite T5 fluid question

HISSIN50

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
#1
Hello,

i noticed im a little low on trans fluid for the T5 (88 GT vert, stock-ish). i try to keep up on this stuff, but some of you are sharper than I, and more 'in the know.'

I'm running Redline D4 right now. seems to work alright. in the back of my pea-sized brain, i still remember people talkin about synchro issues with Redline. i can also locally get Royal Purple Synchromax. I have no experience with the RP. IIRC, the literature says it is intended for manual trannies specifying ATF, so im wondering if it might be tailored a little more for our T5's.

i would love any feedback (of any sort) you might have. :)

many thanks. :nice:
 
#3
What year T-5? The older T-5's from the early-mid 80's had gear oil, but all the newer ones are suposed to use ATF. I ran regluar atf, then M1 5w30 oil and then drained it out and put M1 ATF synthetic in my T-5. It shifter better with the M1 ATF, but then I broke it but when I opened up the case the gears were like new looking and everything was very clean.
 
#7
i have had best results with regular mercon dextron or whatever. I have asked a lot of peolple before using it and that was there suggestion. Although redline is a little more of a product, people have said it causes synchros to go bad. I would just play it 100% safe and use what the factory uses. I mean they do know whats good for their product right.
 
#8
Matt - put the car on stands front and rear (so it's level). Crawl under passenger side, and there are two plugs on the side of the tranny - they have square fittings on them. The lower is the drain plug; upper is the fill plug or fill line. Undo both - catch the old fluid - container needs to hold 3 qts. Once empty, put some thread sealer on the lower plug and retighten it.

To refill you can 1) use a manual hand pump to pump fluid in the top hole; 2) you can run a tube into the hole from the engine compartment, and use a funnel to gravity feed fluid into the upper hole through the tube; 3) you can remove the shifter from the car (interior) and pour the fluid into the top of the tranny through the shifter hole. Any way you fill it, fill till fluid just begins to come out of the fill hole. It will take about 2.75 qts.

Or, you can roll the car on it's roof......
 
#12
Redline has two different ATF fluids they sell: Regular ATF, and ATF D4. The D4 is specified right on the box to use in manual transmissions that are specified for ATF, therefore I don't see how the synchros could go bad. I use it in mine and it shifts smoother than non-synthetic ATF.

One common fluid that you should NOT use is GM synchromesh. They are designed for transmissions with bronze synchros (new tremecs)

90mustangGT- I believe the early SROD transmissions used gear oil. To my knowledge all T-5's use ATF. (World class versions for sure though)
 
#13
thanks for all the replies guys. i was in a rush earlier to get this thread up, so i could buy stuff tomorrow. i left out details.
since i need to spend either 10 bucks, with tax on D4 (what i run now) for a bottle, or 22 bucks out the door for 3 bottles of RP Synchromax, i figured now would be the time to figure out which was best since im muddling with it.

Mav0716, thanks for the info. ive long since tossed my old bottles and did not remember that it specified it was for manual trannies (gonna hit their site later). the stories i read (mostly in vette forums, with 6 speeds) about tranny failure after running Redline always made me wonder if there was something better out there.

on my 88, the shifting can be a little notchy (i just about always granny shift and match revs pretty decently - heel toe). i kind of wondered if the D4 is perhaps a little 'too slick' - and the synchros dont quite grab all the way, as a result.

ill try and find some hard data. i'd hate to drain my D4 (2K miles over 1.5 years on it), for RP, then hate it and have to swap back (it would be an expensive trans fluid top up, which is all i set out to do). i thought someone might have the RP in their ride, or perhaps used both at one time or another (Stangbear, where are you? - i think you have tried one of every product for stangs). :)

again, many thanks guys.
i should ask, as general as it is, with synthetic ATF's, do you have notchy shifting at all?

Jason, let us know how you like the new trans. :) i saw your thread and was glad to hear you were able to get a new one so fast!

thanks again everyone. :nice:
 
#15
89MustangGX said:
I believe the Redline that can cause problems is MTL (in colder weather). The D4ATF is supposed to be very good with the T5.
Click to expand...
Adam, thanks for the reply.
i read some threads in the corral and a group of guys seemed to really bash the D4. but since i dont post over there and dont know the people whom posted, i do give that much creed.
i know i wont get a comparative answer, so i think ill just grab another bottle of D4 to top up my existing D4 in there already. i guess im just curious if people have tried synchromax and if they liked it.
thanks again, Adam. :nice:
 
#16
It was Bob Hanlon who recommended it to me many years ago. He was also the one who warned me about MTL in colder weather, though he did say he preferred it in racing (warmer weather of course).

I wouldn't think twice about running D4, it's the only Redline fluid approved for a T5 AFAIK.

Synchromax I have never tried, nor have I looked into it.
 
#17
89MustangGX said:
It was Bob Hanlon who recommended it to me many years ago. He was also the one who warned me about MTL in colder weather, though he did say he preferred it in racing (warmer weather of course).

I wouldn't think twice about running D4, it's the only Redline fluid approved for a T5 AFAIK.

Synchromax I have never tried, nor have I looked into it.
Click to expand...
Adam, thanks bud. :)
i think Mr Hanlon knows a thing or two and would heed his advice. i had also asked Redline about the use of MTL (im familiar with it, as i run a mixture of it and MT90 in the transaxle on my eclipse) in my stang. it is normally driven in ambient temps of 60*-110*. i wanted to ensure i was not running something too thin in the heat. they still said to use the D4.
(you are right, AFAIK also - it is what is recommended by Redline). ive not used RP products before, but they have a ton of new vendors, so i was curious (i had used Redline cuz it is available locally).
thanks again, bud.
 
#18
man im getting confused....manual trans using ATF? chilton says use ATF too... so i can use any ATF? i'm going to be dropping my trans for a clutch install...i may as well change the trans fluid too...

after reading all these fluids from these threads i'm not sure which to use. i want a fluild proven to work. really don't need redline or royal purple. just oem stuff will do.
 
#19
i cant remember what flavor of atf we use offhand. i would look it up and use the appropriate type. i think all WC T5's use atf.

BTW, for 21 bucks you can run synthetic - think of how often you shift and how seldom you need to change the fluid. hence why i run synthetic. some guys do prefer conventional atf. to each his own. :)
 
#20
Well, I have been using the Redline MTL since october when I did my T5 conversion, and with nothing else to reference against, the shifts seem buttery smooth. 89Mustang mentioned the MTL and cold weather don't mix, but since it never gets cold here in Hawaii, I have been putting of changing the fluid to the D4. So far so good.
 
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