tried to use the search function on this topic but this forum is just huuuuge.
I have a small problem i wanted to finaly tackle.
Ever since i got my 2.5 fiero (85) with auto trans, it has a little problem. When i go over 75 to 80 mph the trans starts shifting back and forth causing a stutter. Also the tach starts jumping around when it happens. All plugs down to the electrical parts of the engine seem to be ok. The auto has a proper oil level and no leaks visible. I'm not sure if the engine is causing the auto to shift back or if it's the auto itself doing this. I've done a lot of adjusting to the auto with the help of a mechanic. Nothing seems to make a difference.
When i stay under this speed the engine and auto transmission are running like champs. No oddities and a smooth shifting.
So i'm walking around with a large question mark bubbling above my head. I'd like to get rid of that.
Anyone know where to look at next? Thanks in advance!
IP: Logged
09:48 PM
PFF
System Bot
Aug 10th, 2008
linuxpowered88 Member
Posts: 1220 From: Johnson City , TN , USA Registered: Sep 2007
Sounds like the tranny is not actually shifting but the Torque converter is locking and unlocking. Remember the auto tranny in the fiero is only a 3 speed. 2nd gear at 75 would blow the low revving duke into a million pieces. Prob need a new trq converter but im not tranny expert.
IP: Logged
02:35 AM
Raz50 Member
Posts: 81 From: Dordrecht, Netherland Registered: Aug 2006
It's kind of narrowed down to the TC as Linux said.
It seems at a certain speed (or at about 3k rpm) my TCC keeps locking and unlocking causing a light stutter and a jumpy tach. Is there any way i can perform service to the TC or try things to test it? When i press the brake pedal just slightly it unlocks, so that's working. Anything else i can try?
IP: Logged
05:37 AM
Aug 12th, 2008
2.5 Member
Posts: 43225 From: Southern MN Registered: May 2007
I had a similar problem with my 84. After changing the lock up silonoid (very easy job and only 12 dollars ) with no luck the alternator went out. New alternator fixed the problem for me. Something to keep in mind at least. Best I can figure the alternator was not supplying sufficiant voltage for the lockup silonoid to work properly.
[This message has been edited by Fieroseverywhere (edited 08-12-2008).]
IP: Logged
07:01 PM
Fieroseverywhere Member
Posts: 4242 From: Gresham, Oregon USA Registered: Mar 2006
Kickdown cable? If Fieros have them same as older cars it may be trying to kickdown to pass when your pedal gets down far enough to go 80mph.
For the 84 and 85 dukes it is extremely easy to adjust the kickdown cable. Literally push a button and move the cable housing. I'll post some pics as soon as my camera charges up a bit. This is a distinct possibility if it is not adjusted properly. Later.
IP: Logged
07:08 PM
Fieroseverywhere Member
Posts: 4242 From: Gresham, Oregon USA Registered: Mar 2006
It's kind of narrowed down to the TC as Linux said.
It seems at a certain speed (or at about 3k rpm) my TCC keeps locking and unlocking causing a light stutter and a jumpy tach. Is there any way i can perform service to the TC or try things to test it? When i press the brake pedal just slightly it unlocks, so that's working. Anything else i can try?
Unplug your TCC. Wont hurt anything but gas mileage and should give you a better idea of where the problem is. Been there, done that, don't want to do it again. Later
