Guys, help me, this damn transmission.. :(

Here's the story:

I went to get the Tranny fluid changed on it (It's a T5OD Tranny) and the Manual says to put Mercon in it. I went to a Mr. Lube (I don't know if you guys have them in the US) and I asked if they would put Mercon, but they didn't put Mercon, they put Castrol Syn AFT (According to my receipt)

So I notice that the Transmission is a lot harder to shift, and I think "Ok, maybe it's just the fluid that needs to work it's way in" So I drive it around for 2 weeks and nothing. I go back and told them what was going on, and they said "Ok, no problem, we'll switch the fluid" and I go "Don't you guys have Mercon?" and they say "Yes we have it" so I go "Ok put that stuff in" and they do. I drive it around for 10 mins and find it's even harder to shift now, so I go back and ask them "Are you guys sure you put Mercon in this thing?" and they go "Yeah, we put Mercon V". I go "No crap, Mercon V is not compatible with this" So they go "Ok what do you want us to put in it? So I search the web and find that Ford dealers use the Mercon/Dexron III fluid. So I go "Put Dexron III" and they did.

So shifting got marginally better, not by much. I wonder if I still have the wrong fluid in this thing.

Here's the problem I'm having:

When I shift into gears, sometimes it will ease in, and sometimes it's very hard to shift into it. It's especially noticeable when I shift at higher RPM's, but always intermittent (Like, I'll be stopped at a Red, and it goes Green, so I put it on 1st and take off, and putting it in 1st was easy, but I get to the next Red, and then when I take off, it's very hard to shift to 1st, to the point that I have to force it to go in hard. It does this intermittently in all gears, but 1st and 2nd are the worst.

What the hell? Could this be syncro damage? Can anyone recommend something to me please? I am going to complain to that company (maybe write a letter to the corporate office). If I need to get the tranny rebuilt, I'm looking at minimun $600 US, maybe more. But maybe it's just the fluid is still wrong? What's the best stuff I can put in this? I am going to change it myself, and hope for the best.

Guys, thanks to all in advance, can't believe how much bad luck I'm having here :(

I would get ahold of them one way or another and demand another tranny. Also it may be best legaly if you didnt do anything yoursekf to the tranny at this time. Incase they try to bring it to court and say you screwed up and tryed to put it off on them.

I keep reading that Syncromesh is a good fluid to put in Manual Trannies. I was trying to find this stuff everywhere but no one carries it.

Even Online I can't seem to find anything, crap.

We did a tranny job at work that required synchromesh. I think it was a ford too. My boss had a hard time finding it.

Wow, I thought you guys would know this stuff, I guess you don't :(

your shifting problem sounds like a syncro problem and nothing to do with the tranny fluid.

As far as fluid goes, different years require different type of fluids. Pre 88 Mustangs used Dexron II ATF. Post 88 Mustangs used Mercon ATF, to sum it up breifly.

When I just installed my "new" T5, I used Mobil 1 synthetic ATF.

So to put this one to rest....89 gt 147k miles but only 12k on the new tranny...which type should I use? and is it easy to do or should i take it somewhere?

I have a Tremec T5 transmission service manual.Borg Warner was bought out by Tremec a few years ago. In the service manual it states to use Dexron II automatic trans fluid. It also states "DO NOT mix different brands or types of transmission lubricants in the T5 transmission since this may damage the blocker ring material".
It was explained to me that what ever Dexron II has in it grabs and holds on to the blocker ring material and lets the trany work properly. When you switch types or brands It may not be slick enough or lubrcate properly causeing hard shifting and blocker rings to fail.

take a 3/8 in. drive socket wrench (don't put any sockets on it),get under the car and pull the lower set screw out let the trannsmission compeletly drain, put the plug back in, remove the top plug and get a funnell with a hose on it, run it down through the hood and fill it till it overflows (should take 2.75 qts.) use royal purple synchromesh and put plug back in (you might want to put teflon tape on the threads to gurantee a good seal.

Even better yet you can take the shifter off and pour the fluid in threw there.

Folks, as far as your standard trans is concerned, all ATF fluids meet the same standards, regarless of brand EXCEPT the Type F fluid. This is intended for pre '77 auto trans Fords, and some old Hondas and Toyotas. This stuff lacks a friction modifier the other ATF types have.
So you are okay with anything except Type F.

I think this trans has other problems unrelated to the fluid. A flush and fill with some synthetic fluid sounds like a good idea, to start.

Type F was and is also used in some GM trannys for a harder-later shift.