What causes the '90s galant auto transmission to fail?

Hey guys,

Today, after getting tired of all the hard shifts that my auto trans gives me while driving, I installed a heavy duty, truck-sized transmission cooler in the bottom-left part of the bumper. This cooler is in addition to the stock axillary cooler and radiator cooler that I already have.
(Trans fluid: flushed 4x. Filter: changed once. I'm using standard Dex III/MercIII Advanced Auto brand ATF)

Everyone seems to hate the auto transmission from this model year (including me).
Does anyone know/have a good idea as to what causes these transmissions to fail so early? Is it a transmission overheating issue? Or is it something far more complicated, and thus not as well understood?
Thanks! :icon_wink:

From what I have been told there are cast aluminum parts in the trans...aluminum under heat and stress...not a good mix. I am not 100% if all this is true, but this is what I have been told by trans shops. Eventually, even after normal driving, you will get that clunking

I've had three 7g auto trans fail. One on a 94 at 200K miles, one on a 95 at 143K miles and one on a 98 at 140K miles. In each case the first sign of a problem was the failure of the trans to go move the car while in reverse. On the 94 this went on for months before the forward gears were effected. Eventually it just did nothing in forward or reverse. On the 98 we returned from a 3,000 mile road trip and a week later, it refused to do anything at all in reverse. The forward gears were 100% in limp mode, telling me it had serious internal damage. I had the 94 rebuilt, the 95 is going to be a parts car and I'm planning 5 speed swap on the 98. When I get the trans off the 98 I'll check and see if I can determine what specifically went wrong.

i had my tranny fail at 120k, then rebuilt by the best auto tranny shop around here and it failed 3 more times and was rebuilt every time with all new parts, i finally put a used auto in it and it ran great, that auto tranny had really low miles on it though, but it seems when the old tranny went it must have cause a lot of damage and led to a misalignment or something as when the tranny failed the next 3 times it was something different every time. now im 5 speed and wish i did it way sooner

same, I had 2 trannys blow out on me with normal driving. I swapped mine to 5 speed and I agree I should have done it sooner as well

as for the reason why, i have no idea. my auto went out at around 140K, had it rebuilt by the fucktards at AAMCO, and it was actually WORSE when I got it back. yeah it shifted gears and drove but it might as well have been retarded hamsters skidding across running wheels.

they denied anything was wrong with their job and refused to fix it or do it right. i despise confrontations, even if i'm 100% in the right, so i did the 5spd swap and found salvation.

Thanks guys. It seems to be caused by a number of different things apparently.

I fitted an external transmission cooler that's designed for cars and trucks towing up to 5,000 lbs :005: Hopefully this will help prolong the life of it. I also drive it like an old person. Hopefully I'll be in the clear for a little while.

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<b> Re: replacement transmission</b>

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Wheres a cheap place to order used transmissions

My 94 trans just went out but im not sure if its the trans or the linkage.... i can move the shifter with no problem and i can put it in drive but the car wont move at all so i have no clue whats wrong with it. The trans has 199k on it so im thinking about either swapping it or putting a used one with less miles in it. Any suggestions?

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Originally Posted by madbmxer963

My 94 trans just went out but im not sure if its the trans or the linkage.... i can move the shifter with no problem and i can put it in drive but the car wont move at all so i have no clue whats wrong with it. The trans has 199k on it so im thinking about either swapping it or putting a used one with less miles in it. Any suggestions?

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The transmission linkage is under the hood next to the ATF fill-up tube. Have a friend check to see if it moves when you move the shifter. If it doesn't move, the linkage is broken. If it moves, it's probably the transmission.

For future reference to anyone on this forum with the crappy F4A23 auto transmission:

To extend the life of this failure-prone transmission, the most effective thing you can do is increase the cooling capacity of the transmission oil. The stock external cooler and cooler inside the radiator simply aren't enough to keep the fluid from cooking itself. In addition to the stock coolers, I recommend fitting another cooler. The one I installed on mine is designed for trucks towing 3,000 lbs or more. I picked mine up from Advance Auto for around $25.

Doing the above will cut the operating temperature of the oil dramatically. The lower the fluid temperature, the longer the transmission will last.

first off, dex III/mer III is the wrong fluid to be used in that transmission, u should be using Diamond SPIII, anything else would cause the transmission to fail, i went thru 4 transmissions on my 7g, one of them being a level10 bulletproof transmission, all of it coulda been saved if i just used the correct fluid

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Originally Posted by QnzMostWanted

first off, dex III/mer III is the wrong fluid to be used in that transmission, u should be using Diamond SPIII, anything else would cause the transmission to fail, i went thru 4 transmissions on my 7g, one of them being a level10 bulletproof transmission, all of it coulda been saved if i just used the correct fluid

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Very true. Although I've been running DexIII in my tranny for 20,000 miles with no problems, I plan to drain + flush my transmission and replace the old fluid with Castrol ATF multi-vehicle. It's cheaper than the OEM SPIII and I can get it right here in town without having to order it. They claim to be compatible with Mits Diamond SPIII, as per this article on their website:

http://www.castrol.com/liveassets/bp...ehicle_ATF.pdf

tanks for that ive been trying to find it cuz i thought it was under the car which is where ive been looking. ill have to look at that tomorrow in the light but if it wasent the linkage how much would a new trans for a galant cost or would it be cheaper to do a 5 speed swap or is it possible it could the the torque converter. I really dont know anything about these cars or transmissions at all so this is really a first for me with all this.