What Fluid to run in my T5

Ok, this thread confirms that I possess an immense capacity for foolishness.

I had a mechanic friend of mine go through the car and check stuff out for me. He informed me that my transmission fluid was low (I had been experience difficult shifts) and that he added some synthetic fluid for me. It was some 75w-90 Durablend or something (this was a couple months back).

My T5 is supposed to be running ATF? Well, that may help explain some of my problems. If this is true AND its a problem, will I be able to drain the stuff out completely and add ATF without any major side effects?

Sorry 'bout that Mike - your mechanic should've known better. I'd buy 3 quarts of regular old Dextron III/Mercon and 3 qts. of whatever you want to run in it. I'd drain the lovely mix of hydrocarbons you have in there now. I'd put the regular atf in and take it for a long enough drive to mix things up/heat things up real good. Then I'd drain that and put your good stuff in there. I'd also let the mechanic know about his screw up - if there are problems with the tranny going forward related to his faux pas, I'd put him on notice now, not then. You might even save a bit of what comes out and have it sampled so you know what was actually in there.

Thanks for the advice, man.

The mechanic is a close personal friend of mine, and he does EVERYTHING for free (he said he would charge me if I still had a GM, but he loves Fords). He's likely going to feel really, really bad when I tell him about this so I'm sure he'll do what he can to take care of it. He said that his connection at Napa was a huge Ford enthusiast and recommended the fluid. The guy at Napa (he's the manager, sadly) clearly doesn't know nearly as much as he says he does.

Manager at Napa =

Maybe he can get me a new T5... Real, *real* cheap if you know what I mean.

<threatens to call Better Business>

Oh well. Do you think that any of the nasty grinding noises will vanish when proper, clean fluid is swapped in?

Since I was too lazy to crawl under my car and change the oil in the tranny, I got the local mister lube to do it. After about 15 min of arguing with the guy I finally convinced him that the tranny took ATF. So watch out there is not alot of knowlege of this in this world. By the way, I was using reg. ATF, but recently switched to mobil 1 synthetic, it shift alot smoother now!

Mike said "Do you think that any of the nasty grinding noises will vanish when proper, clean fluid is swapped in?"

That doesn't sound real promising to me Mike - but you've got nothing to lose from trying. Was it grinding before the gear lube was added to the atf? Perhaps the low fluid level is what caused the problem. How'd the level get low - she leaking?

If you take all the comments in totality, I think consensus is just run a quality fluid, and change it out every so often. You got the one guy with almost 200K on non-syn fluid (most T-5's out there - they came in a BUNCH of different cars, not just Stangs - fall into that category); and you got guys that are certain the tranny will fall out of the car if you don't keep syn in it. I don't think it makes a whole bunch of difference. I suspect the biggest variable is to keep it relatively clean - changed every so often. I only used the Amsoil syn because my brother's shop lets me have it from free. Can't beat that price. Otherwise I'd've probably just dumped Dextron III in it.

If you're racing the car or beating on it hard or subjecting it to higher or lower than normal operating temps (towing jetskis in south TX; cold starts in Calgary) I'd run a synthetic - they handle the temps better. Otherwise, I don't think it'll make a whole lot of difference. Some claim amazing transformations after a switch to syn - in most cases I suspect just getting the old fluid out and getting new fluid in would accomplish much the same. Have fun with your selection - unless you put 90 wt. gear lube in there, I don't think you can screw it up!

I'm going to get told I am crazy and my tranny will blow up by some, but I run the Redline MTL in mine.

I bought this T5-Z in August 2002. Put it in with regular ATF, then changed it out at about 1500 KMs. NOTCHY is an understatement. Put in Mobil 1 synthetic ATF, for a couple thousand KMs.. still NOTCHY as all hell, can't speed shift let alone powershift, I thought something was wrong with the tranny to be honest. And so.... in April 2003 I went to the Perf store about 1/2 hour from here and they had Redline MTL and and the other one that was the D4 I think everyone is mentioning. I ended up buying the MTL. Cause.. for a long time I remember MTL being "the stuff" to run in the T5s back in the Stang mags in the late 90s and stuff.

I remember a few people, can't remember which, either here or Corral telling my I was going to fry the trans cause I bought the wrong stuff etc. I did call a few places... and talked to a guy at D&D and he said that the MTL was fine and lotsa people had used the stuff. I can't remember which other places I called [jus grabbed a Stang mag] but every other place said it was fine. D&D I remembered cause thats all they do is trannies..

Even though its numerically rated a gear oil, it looks like & pours out at about the same consistency as ATF. It's a tad thicker but barely noticable. Infact I filled my T5 up using a oil squirting can with a vac hose on the end stuck up in the fill hole [I know, pretty ghetto ] and kept filling the oil can with this stuff and pumping it in... thats how thin it was.

Anyways, soon as I put the Redline MTL in mine I noticed about a week later it was real nice to shift just driving it, and I was able to speedshift and powershift. Another thing I notice, when I just had regular ATF in all my other Stangs [89 GT and 91 LX.. 5.0 5 spds.], on a hot summer day after alot of driving, they would become notchy when they got real hot. I notice with the MTL in this one, it is a little notchy if I have to move the car in the winter on a VERY cold day [dont winter drive it though] but from 48* early April spring weather to HOT summer days I can drive all day long and no notchiness or anything and I think thats because the oil doesnt break down and get thinner like the ATF used to.

I wont run anything else now. For a car that see winter use I might use the Redline D4 that is actually rated as ATF and not a gear oil. BUt summer only T5 i'll use the Redline MTL.

Whew!! Finally someone else other than me that runs MTL in their T5. I also have been using MTL in mine for about 8 months now with no problems. The shifts are nice and smooth so far, and the only problems I have are symptomatic of a junkyard dog tranny. I did notice on the back of the container, however that they "suggest" using D4 for trannys that specify a ATF. I have heard that winter driving a T5 on MTL will kill it, so unless the only snow you see where you live is around the nostrils of the local junkie, maybe D4 is a better choice.

I swear by synthetics for 3 reasons:
1) It has a habit of coating moving parts better
2) It's proven to be a lot cleaner (self-maintaing in a way) and less proned to breakdown
3) It flat out makes almost any tranny with synchros in it i've seen shift smoother after running with it for a while (much like my T5)

Michael Yount said:

Mike said "Do you think that any of the nasty grinding noises will vanish when proper, clean fluid is swapped in?"

That doesn't sound real promising to me Mike - but you've got nothing to lose from trying. Was it grinding before the gear lube was added to the atf? Perhaps the low fluid level is what caused the problem. How'd the level get low - she leaking?

Click to expand...

Oddly enough, there was no leak.

Even more oddly enough, we followed your advice... And it yielded some promising results. We drained the gear lube, ran some Mercon V from Coastal (uber generic) for about 10 miles, came back and drained that and ran another 3 quarts of that Mercon V. Now, it shifts cleaner than ever and doesn't grind any more.

You guys are the best. Thanks for the info and the advice

blk92stangg said:

Whew!! Finally someone else other than me that runs MTL in their T5. I also have been using MTL in mine for about 8 months now with no problems. The shifts are nice and smooth so far, and the only problems I have are symptomatic of a junkyard dog tranny. I did notice on the back of the container, however that they "suggest" using D4 for trannys that specify a ATF. I have heard that winter driving a T5 on MTL will kill it, so unless the only snow you see where you live is around the nostrils of the local junkie, maybe D4 is a better choice.

Click to expand...

I ran MTL in one of the T5s I had before, as soon as it got a little cooler -- it was hell on the tranny. I wouldn't run ther stuff just because of that. I'd rather run a fluid that I don't ever have to worry about.