Ok, well I "think" my transmission in my 87GT ran out of fluid this afternoon.

What happened was, I was driving along, and I noticed that when I was coming to a stop that it would take a fairly long time to drop gears. I was about 4 miles from home when I notced this, so I figured I could make it.
Well I was about 1/2 a mile from home and after I was stopped at a light and I started up again, the car just started up with this really loud grinding. So, I managed to pull onto a side street and stopped the car. I open the enginebay up and check the tranny fluid and I notice that i had no reading at all!
I poured about 3/4 of a bottle of tranny fluid in it and let it sit for a few minutes, and then tried putting it back into gear, and it still made this horrendous noise, I also noticed that it did this when I went from drive to neutral until the car stopped completely.
So, I decided to just put the car in neutral and push it home. Well I got stuck in a snow bank, so I had to put the car in gear again, and this time, it worked fine! So I drove it the last 1/4 mile home at 5mph.

Now I haven't gone under the car yet, but did I just run my transmission out of fluid, or could it be something else??
And if I did run it out of fluid, how bad did I damage it? And ideas?
I think I know where the leak is, along the pan for the filter. But it has to be fairly big because I just checked my fluid 2 weeks ago.
Needless to say I feel like a complete moron about this. Hopefully it's not too serious though.

Thanks in advance for any input

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If you ran it dry you could have worn all the clutch plates or belts out. Take it to a good tranny shop. Most of them have rebuilt trannies they can just swap in, although you might have trouble because it's a Fiero and the trannies are getting rare.

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well, I dont mean to be rude or undermining, actually the transmission isn't getting much rarer yet, they are very common, It was used in SO many different models of FWD cars, they are also transmission shops favorite FWD transmission, they are so easy to work on and parts are cheep and plentiful, yet durable too. I totally agree that you should take it to a transmission shop to have it looked over, just be careful to where you throw your money... This is a cheep transmission. Shop around carefully if you need transmission work. The engine and transmission have to come out togather in order to change the transmission, there is ALOT of work when compared to all other cars. So this part of the transmission quest can be costly. But then again, there is always the possibility that you can have the leak fixed and go on happily for a long time, but grinding noises suggest otherwise. Good luck.

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Matt D
1984 Indy Fiero (auto)
1985 2m4 V6 DIS 3.1 Auto

Well, this turned out to be a brake problem and not a transmission problem.

Yes I was about a quart low on tranny fluid, but I found no major leaks that would of resulted in major loss of fluid. Plus if I was completely out, I would of been down more than a quart.

Well, it turns out that my driver side brake caliper somehow worked it's way free of the hub! My father noticed that there was the smell of burning brakes so I looked at the rotors and noticed discoloring on the one rotor. And I'm assuming the grinding sound came from the caliper sliding all over the place.

Anyways, this was an easy fix, I just retightened the bolts and put a touch of locktite on them.

Let me say, it is very nice having a mechanic for a father. I would of found the problem eventually, but it makes it much easier when you have an experienced mechanic around to help.

Why this happened?? I don't know. The other side was fine, so my father and I concluded that one of us just forgot to tighten those bolts real good and they just worked their way looso

Actually a quart low is about totally out... a huge portion of the running oil is trapped in the TC and cooler set(lines and cooler).

At a quart low most automatics start sucking air. Some more than others.

You probably didn't hurt the tranny any. If it's sucking air it will loose pressure and effectivly drop out of gear.

Even if the tranny did fry.... I'd just go get another used unit in decent shape, check it over good, and put that in. There's no sense spending allot of money on a transmission that's nearly as common seagulls at a landfill.

The other advantage to a used unit is you can find a later model one that has more of the known weaknesses worked out of it. GM made rolling improvements to that transmission just about every year. TH125 is pretty decent as 3 speeds go but why settle when you can likely find better for less that fixing the one you've got? (There are several TSB's on the TH125 outlining the most common items to break.)

If it fried this would also be a good time to consider moving to an AOD unit... That gives you a chance to improve fuel mileage and/or increase launch torque. Maybe both if you pick carefully.

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11-Sept-01, The day the world as we knew it ended.

quote Originally posted by theogre: Even if the tranny did fry.... I'd just go get another used unit in decent shape, check it over good, and put that in. There's no sense spending allot of money on a transmission that's nearly as common seagulls at a landfill.

Here here!! I can't give away auto trannies, so if you did fry it (although it sounds like yours is OK) just buy a junkyard one for $50 and spend a nice weekend swapping it out.

Worse case scenario is the "new" one is bad, which is doubtful. That sure beats the $1000 cost of rebuilding your old one (with R&R)!

I would personally go the route of a 4-sp. auto (like theogre suggested) if my tranny ever went south on me.

So... if my original auto is needing replaced, which AOD unit would be the best (and what work other than the swap would be required)? '84 2m4. Thanks

I think I'll post the GM diagnosis charts for the THM-125C transmission on my tech site - I'll keep you posted

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Eric Nelson
Technician,
West Coast Fiero
www.cwestco.com
310-305-4111

My son had his 84 at Clarkson University where it was dropping out of gear at stoplights. I told him to add fluid. He didn't. Subsequently he drove it home 350 miles to Buffalo.

I found the rubber hose in the engine compartment to the transmission cooler had a leak. It took five quarts of fluid to fill the tranny. That was three years ago and it still runs just fine.

So my sage advice to anyone who has run low on fluid is to fill it up and see what it does. Don't rush to replace it, you may not need to. These trannys are tough.

I hope you kicked your son in the ass for doing that.

AkursedX

It's good to hear that your got your Fiero fixed. On a related note, I don't think you have to worry about your transmission being fried because of the low fluid. The T-125 transmissions are basically "bullet-proof". The auto tranny in mine has endured worse and still works just fine to this day.

Almost 2 years ago, the tranny in my 87 SE ran dry. I was about a mile away from the house when the tranny started slipping out of gear. I pulled off the road and during the few seconds that the car was parked (with the engine running), it threw about a quart of tranny oil on the ground. Tranny oil was spewing out the transmission like a faucet.

For about the first half mile, it would go into and out of gear, but the last half mile it just gave up. Luckily, I had a gradual downhill slope the rest of the way, so I just coasted it home.

When I got home, I looked at the transmission and found tranny oil ALL OVER the engine compartment. The two rubber hoses that come off the transmission were rubbing together, and wore a hole in one of the hoses. I ended up walking down to the local auto parts store and buying some neoprene hose and tranny oil. It took about 4 quarts to fill it up, so it was almost dry.

That was almost 2 years ago. I'm still driving the car (my daily driver) and the transmission still works just fine to this day.

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Tweaktech

Blacktree-
I noticed the "Black Sunrise" in your signature. I used to be part time help for a stor called Black Sunrise, they sold all sorts of goth appearal and the sort. Gave me a good laugh.

Anyways, my tranny is working fine now, thank goodness. It appears that it was the loose caliper that was the problem. But if it did go, I would of taken your advice and just went to a boneyard to pick one up. No overdrive for that car though, it's only my winter beater

Im glad your tranny seems to be okay, but ive got to make a comment to this thread. Ive givin myself a crash course on the th125 (3t40) tranny and yes they are common. However, you cant just pull one out of any car you find in the junk yard and expect your car to perform the same. The Gears in 6cyl fieros are for performance "off the line" alot of the th125 (3t40) trannys that you find at the junk yard have final drive ratios like 2.32 , 2.53, or 2.84 . which would be fine for a highway cruiser or a family sedan. but if you are use to the 3.33 in a Gt you would be very disipointed in the performance after a swap. Just keep gears in mind when looking for a replacement tranny.

My 2 cents