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TH125 gurus? by virtuetovice
Started on: 12-18-2014 07:48 PM
Replies: 12 (344 views)
Last post by: Lou6t4gto on 12-30-2014 02:15 PM
virtuetovice
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Report this Post12-18-2014 07:48 PM Click Here to See the Profile for virtuetoviceSend a Private Message to virtuetoviceEdit/Delete MessageReply w/QuoteDirect Link to This Post
When I took my 85 GT 2.8 for a ride Monday, she was shifting and driving fine for a while. After about 20 minutes rolling around it stalled at a stop. I started it back up and as soon as I put it in gear, it stalled again. I was in a turning lane about to drop into a parking lot so I just limp-rolled it in. I checked the fluid and she was low, so I added a couple quarts. At that point it seemed I added a bit too much, maybe a quart over or less. Drove it around the parking lot for a few minutes and all seemed fine, then out of nowhere it felt as if the trans was slowly disengaging until it went nowhere in drive. Went into reverse with a bit of hesitation. I let it sit for about 5 minutes or so and tried again and it went right back into gear. Drove around again and the same thing happened. It faded into not moving. So at that point I decided to check the temperature of the bellhousing with an infrared temp gun and the casing was at about 190. I could be wrong but I feel like that's a bit high considering it's probably a lot hotter inside. I parked the car and dropped into the nearest bar and let off a little steam, I was kinda pissed haha. After about 2 hours the temperature was about 90 degrees so I decided to give it another go. It made it pretty far down the road but again it slowly faded into not propelling the vehicle. I stopped, turned the car off for a minute, started it back up and put it back in gear and again it would cruise for a bit then drop the gear. At that point I phoned the lady and she used the Regal to push the Fiero back home. [what a sight that was, many funny looks happened.]

So my questions are...is the temperature unusually high and if so OR NOT, what could possibly be causing this? Did I possibly cause more damage overfilling and then attempting to drive it a few more times? I've been reading around a lot but the only information I have gathered that's relevant is: my car stalling initially was more than likely caused by the TCC solenoid sticking, and overfilling too much CAN cause some odd problems. I plan on draining a quart out of the car this weekend.

Any input, criticism and suggestions would be greatly appreciated.
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fierofool
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Report this Post12-18-2014 08:14 PM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageClick Here to Email fierofoolSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
The first symptoms of stalling sounds like the TCC switch failed. It reacts like stopping a manual shift car without pushing in the clutch. It just chokes the engine down.

I can't address the slipping problem. Just don't know enough about automatics, but it might be worthwhile to drop the pan, change the filter and go back with 4-5 quarts of Dexron II.

The temperature of the bellhousing isn't what you really should be concerned about. A good place to check would be the pan or the main case of the trans since that's where the fluid is. The fluid is what keeps it cooled by circulating through the passages of the radiator.
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theogre
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Report this Post12-19-2014 09:13 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
TCC solenoid is usually problem when stalled in gear.
See my Cave, Automatic

Over filling can cause "dead" trans. Major Over filling then oil will be whip to foam, pump sucks foam, foam looses hydraulic pressure and trans won't work.

disconnect plug on trans case to stop TCC funtion.
remove extra oil. Get cheap pump to suck oil thru fill/dipstick tube.

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Will
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Report this Post12-19-2014 03:04 PM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
The transmission is bolted to an engine that runs at 195-200+ degrees, so 190 degrees on the bellhousing when the engine is fully warm is not surprising at all.

The transmission fluid should be checked hot with the engine RUNNING and the shifter in park. I assume you did this, since you're no stranger to topping off trans fluid.

If you've overfilled, you may have problems, as Ogre mentions.

As Fierofool said, the first stop sounds like the TCC solenoid got stuck.
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jaskispyder
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Report this Post12-19-2014 03:08 PM Click Here to See the Profile for jaskispyderSend a Private Message to jaskispyderEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yup, unplug the TCC and see if it gets better.
Common enough issue on this tranny.
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virtuetovice
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Report this Post12-19-2014 06:06 PM Click Here to See the Profile for virtuetoviceSend a Private Message to virtuetoviceEdit/Delete MessageReply w/QuoteDirect Link to This Post
Alright so what I'm understanding is that I'm mostly correct aside from the temperature possibly being an issue. As far as the TCC solenoid sticking, is there a possibility that it was sticking due to low fluid?

As far as overfilling, it would be safe to assume that:

The fluid is being turned into foam as it moves around moving parts that aren't supposed to be submerged. At first, the fluid has no air bubbles and retains pressure in the trans but as it gets thrashed around from moving, it turns into foam and is no longer an effective hydraulic fluid? After a few minutes of sitting the foam dissipates and is once again maintains pressure effectively until it is again turned into foam. This would be a pretty solid explanation for the "dropping gear" symptom mentioned, and would also explain why it works fine after sitting for a bit.

So now my primary resolution is to remove about a quart,check for a proper level and take it for a drive. Then I should perform the TCC lock/unlock test a few times in a row and see how everything works out.
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virtuetovice
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Report this Post12-20-2014 02:44 PM Click Here to See the Profile for virtuetoviceSend a Private Message to virtuetoviceEdit/Delete MessageReply w/QuoteDirect Link to This Post
So I pulled a quart out of the trans and Its darker than it should be. Doesn't smell burnt but its dark. This was brand new fluid with under 10 miles. After removing the quart of fluid which put it to the proper level, the trans is still doing the same thing. It goes into gear and drives fine for a minute, then drops the gear as if going into neutral.
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virtuetovice
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Report this Post12-20-2014 05:17 PM Click Here to See the Profile for virtuetoviceSend a Private Message to virtuetoviceEdit/Delete MessageReply w/QuoteDirect Link to This Post
Dropped the pan and ugh...black goop all over the magnet along with small flat black chunks. She done?
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OldsFiero
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Report this Post12-22-2014 07:45 AM Click Here to See the Profile for OldsFieroClick Here to Email OldsFieroSend a Private Message to OldsFieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yup. Stops moving cause the filter is plugged from the failure. The small flat black chunks are burnt friction material.
Sorry.
Marc
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theogre
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Report this Post12-22-2014 10:17 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Toast.
Get another is easier and often cheap.
Get newest year of used parts. TH125c/3T40 have many charges to make them a bit stronger.

Overfill or low fluid can have some pressure but not enough. You drove so friction parts can slip, get very hot and fry off.

You temperature means little here too. Case and oil temp often have enough mass and can hide slipping bands or clutches. Main oil heat source is unlocked TC and heat exchanger in the radiator. Heat exchanger is to heat oil in winter, cool down in summer.
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Will
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Report this Post12-23-2014 05:12 PM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by OldsFiero:

Yup. Stops moving cause the filter is plugged from the failure. The small flat black chunks are burnt friction material.
Sorry.
Marc


Contact Jon Lagler... he's near Allentown, PA and has a TH125 on a pallet that's going to be scrapped.
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theogre
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Report this Post12-24-2014 11:43 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Will:
Contact Jon Lagler... he's near Allentown, PA and has a TH125 on a pallet that's going to be scrapped.

Nice but...
virtuetovice
From: Norfolk VA USA

Drive to or shipped from will cost as much or more then getting them locally.
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Lou6t4gto
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Report this Post12-30-2014 02:15 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
Time to install OverDrive
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