I have an automatic 1988 Fiero GT and I need to replace the TCC Transmission Lockup Solenoid.
Does anyone know where I can buy a new one? If interested, I posted my Fiero problem several weeks ago under "Engine Stall" and was expertly referred to Chuck Kichline's excellent article that describes my vehicle's problem perfectly. I just need to order the part now. Thank you in advance very much!
You can get the solenoid, gasket and the case connector for the THC125 at TranStar on Goshen Springs Road in Norcross, Ga. Cheapest place you will find. They are a supplier of most of the major transmission repair shops like Mr. Transmission, AAMCO, etc. I would suggest you change out the TCC Case Connector while you're in there. That's the plastic piece that the solenoid plugs into the back side and the engine bay harness plugs into the front side. By this time they're usually getting brittle, and if they should crack and come loose, they blow trans fluid out into the area of the catalytic converter and exhaust downpipe.
The easiest way to connect the solenoid to the back of the TCC Case Connector is to remove it from the case and push the wires through and plug them on. Those latches tend to break off when you depress them to separate the old one from the case and it's best to have a new one on hand.
[This message has been edited by fierofool (edited 05-02-2018).]
You can get the solenoid w/ wiring in the trans under Torque Converter Clutch Solenoid at RA like ACDELCO 8689901 for $27. doesn't include 3nd gear switch or trans case plug.
Maybe just changing fluid will stop this. Dirty oil can plug the solenoid too. Need 8-9 q oil and filter "kit" (filter seal and pad gasket.) See my Cave, Automatic
------------------ 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)
Thank you very much for your help! Your information was spot-on and thanks to you I just ordered the solenoid, gasket and connector for the TH125C transmission from TranStar in Norcross, GA. You're absolutely right - they are inexpensive and their customer service was great. Part arrives tomorrow.
Before your reply, I had placed an order for this solenoid from the Fiero Store, however the TCC solenoid on their website appears different that the one in your picture so I checked the GM Fiero manual and the TCC solenoid pictured therein appears similar to the picture you provided. So to be safe I placed both orders (Fiero Store and TranStar) and will return the one not used. Thank you again for your excellent help and advice!
Thank you very much for your recommendation and advice. The TCC solenoid I ordered from TranStar was also inexpensive at $20.95. I totally agree that changing all the fluids regularly is the key to keeping any engine running smoothly for a long time. Thanks again for your advice and help!
Andrew, the picture I posted is for the plug that goes in the transmission case. It facilitates connecting the engine bay harness to the solenoid harness. The solenoid is an electrical device that plugs onto the 3 prongs shown in my picture. The solenoid looks like this: https://www.fierostore.com/...px?s=54856&d=371&p=1
Something I found is that The Fiero Store solenoid has the short wires as depicted in the above link. The Transtar Solenoid has long wires that plug directly into the back of the case connector so you don't have to cut and splice wires.
FF, Thanks again for your help clarifying the situation! I really appreciate this! I'll probably keep the Fiero Store's unit as a spare/backup and thanks for the heads up about the shorter wiring. Both units will be received tomorrow. If all goes well, I'll let you know Saturday (hopefully) how the engine is running with the new solenoid installed. My Fiero only has 2,000 original miles on her, but things do go bad after just sitting around for 30 years. Thanks again!!
Here's an article I did on replacing the TCC case connector. At the bottom of the article is a link back to PFF, written by Gall757 and used by permission. It details his TCC Solenoid replacement.
Thank you again FF!! I'd be delighted to share some "FiFi" pictures, but I don't know how to attach jpg files in my response post to the Fiero Forum. If there is a way to do it, I'm all ears. If not, I could send some photos to your personal email address if you wish.
I received the new solenoid this morning and immediately brought to my mechanic. Hopefully it does the trick - if not, there may be some other transmission problem lurking within but me and my mechanic tend to doubt this as she's only been driven 2,000 miles in 30 years.
Thank you again for all your help. Pennock's Fiero Forum is simply fantastic.
Fierofool, do you have a part number for that TCC case connector? A few years ago I had to replace my TCC solenoid (and while I was in there I replaced one of the pressure switches). While doing the job it occurred to me that plugging in the new TCC would be much easier if I had a new case connector so as to feed the TCC wiring out through the trans, plug it all together outside the trans, then push the case connector back into the trans. I did not attempt to remove the case connector, but I had ventured a guess that the install would have been much easier and faster if I had a new case connector on hand. When I was done I had searched for a part number for that, but could not locate the PN.
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