Large leak - torque conv, seal or external cooler?

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crawdad
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Large leak - torque conv, seal or external cooler?

Post by crawdad » Thu Apr 19, 2018 5:48 pm

Hi Everyone - just a diyer here with little experience on transmissions. I had no idea why a 2003 Impala 4T65E, 280K, would spring such a leak but it was streaming out at a rate of about a pint per minute from the cover at the bottom of the bellhousing, maybe more, while the engine was running. I dropped the trans and replaced the torque converter and the seal. I removed the valve body to look at the pump drive and o-ring, partly because I was surprised how loose the shaft is at the TC end - but I guess it's supposed to be that way? The shaft splines looked ok and so did the seal, which I didn't change because it looked ok, still above the surface of the shaft, and I'd have to wait a few days to get one. Anyway, the leak has stopped. But I'm curious which you think is the most likely cause between the two. My guess is the converter because the seal just didn't look bad enough to let that much fluid out. Also, it happened suddenly, with no previous leaking. But if the TC was defective, it still has to leak out of the TC seal, correct? There was no break in the weld or anywhere else. One other thing - I had installed an aftermarket trans cooler in series with the one in the radiator. The car ran ok for a week afterwards, then the leak occurred. Could that possibly have anything to do with it? Sorry for the essay. Thank you for any comments.
Last edited by crawdad on Thu Apr 19, 2018 7:04 pm, edited 1 time in total.

carod
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Re: Large leak - torque conv, seal or external cooler?

Post by carod » Sun Apr 22, 2018 7:27 pm

I think you are right, most likly the convertor

crawdad
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Re: Large leak - torque conv, seal or external cooler?

Post by crawdad » Sun Apr 22, 2018 11:12 pm

Thank you for your response. Maybe I'll get a shop to test the converter. I'm curious what it was. I thought maybe the Hayden external cooler caused high pressure somehow since I never tested it but it wasn't until almost a week after the cooler was installed that it started to leak. It's still in place and I'd like to hook it back up but I'm a little worried. Think I'll wait a bit.

Stuart1940
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Re: Large leak - torque conv, seal or external cooler?

Post by Stuart1940 » Wed Apr 25, 2018 6:04 pm

Convertors just don't decide today would be a good day to leak then stop leaking.


What usually happens is the pump bushing gets loose, travels forward and cuts off the return hole.

As for the cooler it was just a coincidence.

crawdad
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Joined: Tue Apr 10, 2018 11:42 am
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Last Name: Crawford
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Re: Large leak - torque conv, seal or external cooler?

Post by crawdad » Wed Apr 25, 2018 8:21 pm

I drove it yesterday for an hour at various speeds and terrain and it seemed ok. This morning it was driven 27 miles to work then parked for 9 hours. Barely a minute after starting, it quit moving and would not move in any gear when going up a slight hill, which is the same thing that happened 5 months ago and started all this. When I arrived there, I was able to drive the car home in rush hour, hot, stop n go traffic, without a problem. Since last December, I've installed new filter, Dex VI, Trans Go Shift kit - just the 1-2 & 2-3 accumulators including new pistons - the common 5-piece GM solenoid kit, new torque converter and seal. The two times I've dropped the pan there were a few small metal fragments with a good amount of sludge; clutch material I suppose. Yes, I've thrown money and parts at it. At 280K, it probably wasn't worth it although it's been an interesting experience. Still, would someone please take an educated guess on what problem is most likely? Now that I've become slightly familiar with this transmission, it's still a mystery, but fascinating.
Thank you!

crawdad
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Joined: Tue Apr 10, 2018 11:42 am
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Last Name: Crawford
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Location: Loganville, GA

Re: Large leak - torque conv, seal or external cooler?

Post by crawdad » Wed Apr 25, 2018 8:36 pm

Stuart1940 wrote:
Wed Apr 25, 2018 6:04 pm
Convertors just don't decide today would be a good day to leak then stop leaking.


What usually happens is the pump bushing gets loose, travels forward and cuts off the return hole.

As for the cooler it was just a coincidence.
Thank you for the response. After the leak, I replaced the converter and it no longer leaked. Usually, I would assume the converter was the problem, since after replacing, it no longer leaked. I can't say that since I know so little about transmissions. I will say the pump drive was pretty loose at the converter end. End play was 1.7 mm and the shaft could be moved from one side to the other of the input? shaft that surrounds it. But, for all I know, it's supposed to be like that. I actually did remove the valve body and took the shaft out. The splines were ok and the o-ring seemed ok too, being slightly above the surface of the shaft. I didn't disassemble the pump. Probably where that bushing is, or the converter?

crawdad
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Just an update for anyone interested

Post by crawdad » Sat May 26, 2018 9:15 pm

The trans has been shifting fine since the last post. The problem I see is with the TAP values. The 1-2 adapts are 20, 20, and 6 psi for cells 4, 5, and 6. The 2-3 adapts are 15, 12, and 5 for the same cells. And all zeros for 3-4 adapt psi. Still I wouldn't know it without the scanner. Shift times are well below .65 seconds, averaging around .25. I still haven't connected the external cooler yet. Temps get up to 205° F. so I guess I should do that.

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