so until yesterday my fiero was my DD. i was out on a Saturday night cruise when i came up to a stop light and when i tried to take off and i couldn't get her to shift up a gear so i was stuck in first so i pulled into a neighbor hood and checked my transition fluid level and it came back just below full when hot. so in order to get home i had to dodge in and out of neighborhoods. i still have park. neutral, reverse and drive but it wont up shift while in drive. my fluid is nice and red and doesn't have any metal particles and is not burnt smelling. any help would be great, thanks!

Welcome to the Forum!

Welcome aboard !

First did you drive over anything that might have hit something ? You could have knocked something loose.

Did you try starting out with the shifter in 1st gear and manually going into second gear when you reach 3 or 4 k RPMs?

Check modulator valve vacuum line and mechanical linkage into the trany. These shift by vacuum if I remember right not by the computer. Check to make sure you have vacuum in the line with a gauge if you have one if not just put a finger over the end with the engine running. The modulator itself can be bad as well.

Good luck

Steve


------------------
Technology is great when it works,
and one big pain in the ass when it doesn't



Detroit iron rules all the rest are just toys.

[This message has been edited by 84fiero123 (edited 09-29-2014).]

Did you loose your speedometer as well? Could possibly be your governor drive gear. They are plastic and when they break the governor will not spin.The speedo is driven off of the governor and the housing looks like this.



taken apart the cover and governor



the governor has the green speedo drive gear on top. The governor drive gear is mounted on the bottom and visable once you pull the governor out.

Edit to add: Not my pics , i pulled these of off google.
------------------
ARCHIES JUNK IS FASTER THAN SHAUNNA'S JUNK
12.3 is faster than a 13.2

[This message has been edited by FIEROPHREK (edited 09-29-2014).]

quote Originally posted by FIEROPHREK: Did you loose your speedometer as well? Could possibly be your governor drive gear. They are plastic and when they break the governor will not spin.The speedo is driven off of the governor and the housing looks like this.

Dirty governor will cause late or no up shift. (And Speedo will work as normal) TH125c and 4T60 are known for this.

DIY Can fix the problem but do not stretch/damage the springs etc. You will be towing the car to a trans shop if that happens.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

The Ogre- what could it be if u loose all gears. Park and neutral work but drive, 1 ,2 and reverse dont. I dont have any leaks and the fluid is full and is nice and red, doesnt smell bad either. All cables are attached and I can't see any other issues. Could a bad governor cause this??

I've been working on cars for over 30 years and I have no idea what transition fluid is???

quote Originally posted by FieroJosh1993: The Ogre- what could it be if u loose all gears. Park and neutral work but drive, 1 ,2 and reverse dont. I dont have any leaks and the fluid is full and is nice and red, doesnt smell bad either. All cables are attached and I can't see any other issues. Could a bad governor cause this??

No.

Remove shifter level on trans and have drivers in car start engine w/ foot on brake then move trans shaft to any gear. (Locking pliers or small crescent wrench are good here.)
IF lever NUT is stuck, Do Not use more force. Should be easy to remove. Use what ever penetrating oil. Just don't soak the switch with allot of oil.

Doing that eliminate shifter, cable, adjustment. this doesn't mess with shifter adjustment or risk breaking shifter cable parts. Cable end is old, likely brittle, and getting the end off trans lever can break it.

Work now then fix shifter, cable, adjustment.
No then some wrong inside of trans Or maybe TV cable problems. Hosed TV from bad cable adjustment or valve problems affects oil pressure for TH125c trans.

If someone change trans filter or filter is old... could be filter tube has failed and trans is sucking air.

Some plugs on outside of trans are test ports but I don't have that info handy now. Those port can quickly tell you if pump is dead, etc. You would need correct gauge and fittings. Trans oil pressure is 100 - 300+ PSI depending on exact what test is done. High pressure is a big safety issue. Hot oil even worse.