I just changed out the filter and fluid on my '89 IROC--it was overdue for a change. After I got everything back together, I refilled it according to the procedure outlined in my Haynes manual: 1) put fluid in until it just touches the tip of the dipstick; 2) turn on engine and move shifter through all positions whilst brake is depressed; 3) continue filling until fluid gets to a level that is "1/4-inch below the Add mark on the dipstick".

I drove it to work and back just now (30+ minutes altogether) and it's definitely shifting more softly than before the change. It's shifting when it is supposed to and I'm not going to say that it's slipping, but the shifts are not at all "positive" like I would like them to be on a sportscar.

What does this sound like to you?


The only possible thing that I think could possibly have gone wrong during the change is the refill--I am not certain that I have the right fluid level. As humbling as it is for me to say that I can't read a dipstick, I just have a really hard time telling where the fluid line is on the dipstick. I've tried reinserting it and looking at it under the sun at many different angles, but often times there's a streak of fluid so high on the dipstick that I know isn't accurate. Thus, if anything, I think I might possibly have *overfilled* it... altogether, I replaced 4.5 quarts of ATF after I changed the fluid/filter. That sound reasonable?

Thanks for any help!

 

Well I went out to check the fluid level again today (after the car had been sitting all night)... turns out that I WAY overfilled it, according to the dipstick. The level was right above that little S-shaped bend that's about 3-4" up the dipstick. So, I went out and drained it some--pulled out nearly 2 quarts worth of fluid to get the level down to 1/4" below the "add 1 pint" mark. Drove it around and it seemed to shift a tad more firmly, although still not like I like it.

When I got back (with the tranny warm), I checked the level again. It was *lower* than it was when it was cold. So I added about one quart of fluid until the level was about in the middle of the "full hot" zone. Test drove it a bit more, and it was shifting very softly again.

I've since readjusted the TV cable so that it shifts more firmly because ultimately that's what I want. I know it's not a smart solution to the problem (it shifts out of first at 3000 RPM under light acceleration with 2.77 gears), but it's all that I can think to do at this point to get it to shift more firmly like it did.

 

The tv cable is never used to control shift points. Putting it anywhere other than where it belongs will ruin your transmission. However, if it was correct before you adjusted it, you may have big problems anyway. I would suggest a pressure test on the trans to see if it is hurt or not.

 

Guess I'll put the TV cable back then.

As I mentioned, the filter/fluid change was overdue. The only way I can think to describe the fluid was that it was a burnt-orange to brown hue and was largely opaque (not mostly translucent like fresh ATF is). Another thing I noticed: when I swirled around the fluid while it was still in the pan, I was able to produce a metallic/silvery streak within it. There was definitely a fine metal "paste" (almost like graphite) remaining in the pan after I dumped the fluid, most of which was attached to the pan magnet. However, I expect that there is supposed to be some of that--why else would there be a magnet in the pan? Having never changed the transmission fluid before, I'm not sure whether or not the fluid was indicative of normal wear or of a more severe problem. As for how the transmission performed before the change: it shifted firmly when it was cold, and shifted much more softly as it warmed up (but never as softly as it does now).

Is it a common occurance to have an otherwise neglected transmission working well before a fluid change but then begin to act up as it gets new fluid? (My dad was saying something about "washing the bands away"; not sure what that means.)

 

Sancho,
Having had my transmission rebuilt like 8 times, the fluid needs to be changed often here in Texas since its so hot. Its normal to get a little metal particles in the bottom of the pan, it looks a little like spray paint. I think the rule of thumb is that if you get more than two quarters (25cents) then you might be looking at a rebuild. I hope when you dropped the pan that you cleaned the pan off with a solvent and didnt use paper towels that may leave lint. That magnet you saw collects the particles so they dont recirculate. You should always air dry the tranny parts, since a tiny particle can get lodged inside the valve body and stick. Trannys run better warm, thats why it shifts hard when its cold and softens up when its hot.
The tranny has steel clutches and hard parts that wear, thats what causes the powder. If you want it to shift firmer, buy a shift kit and put it in yourself or have a tranny place put it in for you. ( You have to know about valve bodies to do this) Press the button on the TV cable and pull it all the way in flush against the bracket, (this is the aggressive setting) and then push the throttle pedal all the way down so it sets the high shift point. You will feel the cable "give" and ratchet to the top rpm point and come to rest. This will get you back to normal. Also, you should only add fluid when the transimission is HOT and you are on a level surface, with the car in park and the engine running. The instructions should be on the dipstick. The transmission is very sensitive to fluid level. I also recommend adding an external tranny cooler, my tranny lasted longer the last time i had one of these things on there. My tranny guy also put in a servo from a corvette, which makes it shift HARD, escpecially in 2nd gear. I am not sure if this is the wisest upgrade though.

Good luck
Lucid

 

Lucid,

Hey thanks for the detailed response!

I wish I had some way of measuring how much metal was in the pan--but there was definitely a spraypaint-like substance in there. The magnet had a quite dense but thin layer on it--it was a pain to clean even with my power washer. I did, however, get the bottom of the pan pretty immaculate before putting it back on.

I have since "perfected" (I think) the fluid level, and it seems to be shifting okay now. I'm sure the transmission isn't in the best condition, but it seems to be doing well enough. I'd already set the TV cable as per the instructions you gave, and it shifts more "conservatively" now, which is what it's supposed to do. I still wish it shifted more firmly, but maybe that's not what it's supposed to do. I *do*, however, wish the 2-1 downshift didn't need as much throttle. Perhaps I shouldn't need to be hitting first with a 350 TPI, but I can floor it in second and it doesn't loose traction. Probably an engine issue, but still--2-1 downshifts would be nice.

Thanks.

 

Get a shift kit!
You will notice the difference. I had the tranny rebuilt a few weeks ago, my tranny guy loves me, i pay him cash lol. We reused the Transcat shift kit from TCI. When you put it into gear from park, it engages instantly and kind of lurches the car, even from reverse to drive. Its more aggressive and shifts are faster. This theoretically reduces tranny wear too since there is less time for the clutches to slip. When i drive the mustang i instantly notice the difference, no more slosh.