Posted a topic a long while back about this, forgot to check up on it, now it's gone, so I'll start again.

One day, I was obviously lacking mind juices of some sort, I decided to take my 85 2M6 SE Fiero (Automatic transmission by the by) for a drive in our field. I did a few cookies and what have you, and then I went to turn around to leave, BAM! Hit a stump in tall grass. ****ed up the steering, popped a tire. Ok, no big deal, got that fixed. But once we fixed that, we noticed it would not shift out of first. So me and my dad worked at it for awhile, nothing, so we kind of gave up for awhile. Then school started again and I took it to my school to work on it in our auto tech class.

So I went home with a friend to drive my car back to school, and I got in the Fiero, plugged the battery in cause it had been draining often, and started it up. Started fine, everything worked nicely. Drove slow down the gravel road, got to the highway and sped up a little, success! Shifted!.... at about 4-5000 RPM, 60 km/h. I'm not sure if it shifted to second or third, don't know how to really tell the difference.

So anyways, I did a few little things to try to fix it in shop class. We drained the transmission, and replaced it with new fluid. Played with the T.V. cable, didn't work. But it we somehow made, "progress". Now, it was still shifting at 4-5000 RPM and 50-60 km/h, but once it shifted, it'd shift again really quick. One thing I noticed when I took the transmission pan off was the magnet to catch shards of metal and what have you was off the dimple. Which led me to believe that the stump knocked it off the dimple and knocked some shards loose into the valve body, causing it not to shift right. So, I had the transmission flushed, and nothing.

Here's an interesting part, before I had the transmission flushed, I had a donut on the front right side to replace the tire I popped. The day before the transmission was flushed, I took it to my dad's body shop and just jacked the front right side of the car up with the jack the car comes with and we had it sit for awhile like that till we got the new tire on the old rim. So finally, we got the tire on and left the shop. From the shop back to school, it shifted as if nothing was wrong with it at all, shifting maybe a tad high at about 2000 RPM. Then we took it down the highway, started shifting late again. Stopped, turned around, not shifting at all.

So, I don't have any idea what's going on with this transmission. It seems like the more I drove it, the better it shifted. Between the time when it shifted at 4000 and 2000, there was a point when it'd shift at 3500. Does anybody on here know what the problem could be?

One more thing to note, after the car had sat awhile, I looked in the trunk, and the little storage section was full of mice house materials. Peas, flax, ripped up paper towel. Is it possible that a mouse chewed something to affect the shifting?

If you know anything that I should check or just have any advice at all, it's greatly appreciated.
Thanks.

Yeah, just one more thing to note, it's just a regular automatic THM 125 C transmission, or 3T40 if you will.

More news on the subject. I took it for a drive today, shifted to second at about 4500 RPM, and quickly shifted to third after that. Seems to be stuck with that shift "pattern" now. I was thinking of just searching for a manual transmission to pop in it, but I'm mecha-poor and doubt I'd be able to find one around here. Anybody have any ideas?

[This message has been edited by Valkyrie (edited 10-22-2007).]

well, the TV cable is the only thing you got to work with.
make sure its still connected inside the trans and at the throttle body

Just a note, Fieros don't make for good field beaters. Unless you put one on a truck frame. They are a tad too low to the ground, and a beater that likes to overheat isn't a good beater either.

I've never had an automatic fiero. Do they have a vacuum modulator? That's what it sounds like to me. A vacuum hose that popped off. Or I guess it could be a badly adjusted tv cable as well.

quote Originally posted by 2.5: Just a note, Fieros don't make for good field beaters. Unless you put one on a truck frame. They are a tad too low to the ground, and a beater that likes to overheat isn't a good beater either.

Hahah, yeah, I found that out the hard way, but it's not like we're farmers or anything, it was a pretty flat field, some jerk had to cut down our trees though and just leave the stumps in the tall grass.

quote Originally posted by fieroluv: I've never had an automatic fiero. Do they have a vacuum modulator? That's what it sounds like to me. A vacuum hose that popped off. Or I guess it could be a badly adjusted tv cable as well.

No vacuum modulator, that's what my grandpa who worked on Fieros in his days as a Pontiac mechanic had thought at first, but later found out they don't have. We've tried playing with the T.V. cable too, but I'm not quite sure if we adjusted it properly. But the thing that keeps coming to mind is the magnet inside the oil pan that collects shards of metal. My grandpa thought that if the stump hit the oil pan, it might've knocked loose some shards into the valve body and caused an issue, but we had the transmission flushed and it didn't fix. It seems like it wants to "fix itself" cause the more I drive it, the more progress it seems to make. Like, after it sat for awhile, it shifted high. Then I drove it a little more, and it gradually started shifting lower and lower, until it stopped shifting all together and started shifting high again.

Try popping the trans pan off again and look up next to the valve body and see if you can see the TV cable coming into the trans. If you can have someone work the throttle and see if you can see it moving. It is possible that the cable is binding and not allowing it to move freely, which would cause your intermittent problem. It's also possible that your throttle valve in the valve body is sticking which would cause the same symptom as a binding cable.

*sigh* Not looking forward to ripping that pan off again. But I guess I don't really have any other options. Would this explain why some days it's shifting low and somedays shifting high or not at all?

I did not see it mentioned previously and I do not have an auto in my car. That said, there is probably a pair of transmission cooler lines that run to the radiator. I would check to see if one of them got crushed or kinked in the area where the popped tire / impact area was. Lack of fluid flow could do all sorts of things.

I was reading this post pulling up the whole hydraulic schematic in my mind and going through all the valve bodies and ports and clutches, etc. My mind was smokin' for an answer, then SCCA came up with the brilliant idea of the crushed tranny cooler lines. As a full time mechanic, I often neglect to look for the obvious, if the stoplights don't work, Iook for a bad switch or bulbs. If the car won't start, I look for fuel pump or ignition problem. I assume too much, I think that everyone has checked their fuses or checked to see if there is fuel in the tank. Jack up the car and look for the obvious damage...I believe the phrase is "mountains out of mole hills"....

------------------
carpe diem

I've been wanting to get this up on an actual lift for the longest time now, but the shops around here are all booked full so I've gotta work with little baby ramps instead. These lines, where would they be located on the car?

Since the steering was damage ,I presume it is the front wheel that is damage,, I presume the front then,, the rear ran over the stump.. check to see if trans mount has been damage,make sure the tv cable moves freely especially at the throttle.it must move very freely,did you ajust exactly as specified im manual . A shop instructor would know . the leading cause of the problem you have (1) TV cable,binding throttle lever and bracket(includes manual linkage inside cab and ajustment) (2) governor parts the wings must move freely.. a severe blow could cause the gears to strip,governor spring could unseat ,,this is one of the best transmissions G.M. ever made,reliable a gem compared to the 4 and 5 speeds trash with thier clutch nitemare and weak shift forks ,let me know if the trans was struck close to the governor,a massive blow could cause damage to the valve body and aux valve, these are the easy repairs.. the valve body is not that difficult,but I recomend you have this done while you are at high school shop ,this is good training for H.S. shop mechanic, there is a certain way to remove this part

[This message has been edited by uhlanstan (edited 10-22-2007).]

TV cable ajustment,1 depress the ajust tab , move slider untill it stops 2 release tab 3 by hand turn throttle lever to wide open throttle(all the way) 4 release // do not use a lot of force to ajust cable..if great effort is required disconect throttle and check for free operation.you could have a bent link in transaxle or at throttle always check the easy free stuff first and eyeball every part look close pull the cable to check for free movement haynes manual has best blowup and ajustment procedure for novice

My dad and my grandpa both looked at the governor and thought it was ok looking. Although it probably wouldn't hurt to give it one more look at. How do you mean "the t.v. cable should move freely"? I don't have any manuals for this car at all so that's making this a tad more difficult. Another thing I noticed with the car was, when it shifts high, it likes to shift as soon as I let off the gas. What could this mean?

My question was "where was the transmission hit by the stump" the governor is up high but a shock could dammage(unlikely but possible) I am looking at the parts you can access your self,, the parts you can access that will cause the problems you have.. the most common problem with this transmission is the T V cable ajustment.it seems unlikely this would be damaged,but it is the first suspect ,, the cable should move very freely.it is possible the tv lever inside is bent,,remember we can not see the car I do not know if the transaxle was hit ,I know the front was hit because of steering problem,if the mount is damaged by a hard blow to the transmission a lot of stuff inside could be altered,, some of the fragments you mention could be in the valve body ,A forum member recently P M me with a problem he had thrown $200.oo at!! it turned out to be loose plug wire! check thoroughly the easy cheap fix first,, we are guessing ,,our post to you are based on experience ,eyeball manual ,and guesswork.. I suspect something was knocked loose and is clogging a small orifice, but you must eyeball and check the easy stuff, before you pull valve body & aux valve body ,in its stock application this is a very rugged transmission,,you have to run into a stump to kill it ha ha every fiero owner should have a manual haynes best for novice,chilton for experienced.. I think that as a former mechanic your grampswould have check the transmission lines to the radiator, a crimped or smashed line would definitly cause this ,others had posted on this so i did not and of course the vacuum line do not remove valve body untill all other parts checked give the lines a really good eyeball,if the transmission works close to proper some time it is a clogg some where,eyeball eyeball look look!! kiss principal

[This message has been edited by uhlanstan (edited 10-23-2007).]

Well, I'm not really 100% sure where the stump hit the transmission, but before we took the pan off, I noticed that there was one clean streak made in the grunge on the bottom of the pan almost right in the middle of the pan, close to the dimple that holds the magnet in place. Yeah, my grandpa wanted to check the lines underneath the car but he had a hard time doing it because we basically had the car sitting up on home-made ramps and he was afraid to get actually underneath the car, so he only got a small glance at the bottom of the car.

My apoligy I just thought you would check the lines first before drain fluid they are easy to check ,,,,jack up driver side ,, place 2 jack stand or some object to prevent fiero crush,if you do not have jack stand use tire with 2x4 ect, we need more female fiero drivers,,have your gramps look at lines he will more easily I D bad line ..look for worst crush area ..if crushed study it intensely and figure out the best way to apply "large" vise grip to crushed area to open the line.if required this takes strong grip,smile at weight lifter,ask to do (joke) do not make worse if recrushed properly by vise grips a small change may allow enough fluid to pass obstruction ,this takes finess you must have confidence you can do this you can replace sections easily the shop class can do this.. a section of line can be replaced with compression fittings as this is not critical line.. many brake shops or hydraulic repair shops can easily repair at reasonable price, your shop instructor or gramps will know.just notice you are in manitoba if in remote area just order good used line from fiero used parts dealer compression fitting is easy repair on even hi pressure line just never use for brake line and clutch line only temporary..if line is crushed repair "immediately"

[This message has been edited by uhlanstan (edited 10-23-2007).]

Well, good news. It's shifting now. Yesterday, I took it for a drive in the afternoon and it was shifting high, but lower than it was. Then last night, I took it for another drive, and it just started shifting nicely. Took it for about 5 different trips, and each time, shifted nicely. Today, drove it to school, shifted perfectly. Drove it home, perfect. So I guess there must've just been something in the valve body and the transmission flush and driving it just got it out. Should probably leave this topic around just in case it decides to stop shifting on me.

Check the lines

Haha, I'll check the lines if it starts messing up again. But now, it's working fine, so there's no need.

Once again, it's not shifting. Yesterday, we changed the exhaust cause it was all rusted off, and changed all the wheels. Today, my mom drove it to town, it shifted for her, and my dad drove it back, and it didn't shift. Then my grandpa took it for a drive and he said it shifted for him. Then I took it for a drive and it didn't shift for me. One thing I've been thinking of, in both situations when it didn't shift, the front end has been lower than the rear end due to wheels. The tires we put on the back yesterday are bigger than the ones in the front, and when it wasn't shifting before, it had a small donut wheel on the front which also would've let it sit a bit lower. Could these be related to the problem in any way?