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03 gmc duramax with 350k (BBT) transmission fun

ashman said:
I've suddenly developed a pretty good tranny leak. :(
I crawled under it to see if I could see where it is coming from but it's hard to tell. I'm hoping that it's just the pan gasket. maybe the cold affected it?

I pulled it into the shop and topped it off and let it run for about 10 minutes hoping to see where it was leaking but all I saw was a couple of tiny drops that looked like they were just drips that shook off of the pan, but this morning I looked under it and there is a puddle under the truck about 4" across. :dunno: It wasn't driven at all, just pulled out of the shop and parked.
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They will leak out of the vent if they are over full.
 
ashman said:
I've suddenly developed a pretty good tranny leak. :(
I crawled under it to see if I could see where it is coming from but it's hard to tell. I'm hoping that it's just the pan gasket. maybe the cold affected it?

I pulled it into the shop and topped it off and let it run for about 10 minutes hoping to see where it was leaking but all I saw was a couple of tiny drops that looked like they were just drips that shook off of the pan, but this morning I looked under it and there is a puddle under the truck about 4" across. :dunno: It wasn't driven at all, just pulled out of the shop and parked.
Click to expand...


I can tell you if you have a stock torque converter its most likely that. They are prone to crack. I now have a billet converter.
 
max 02 said:
They will leak out of the vent if they are over full.
Click to expand...
I don't think that is it. It's the same pattern it's been leaking for a few weeks now.

jekquistk5 said:
I can tell you if you have a stock torque converter its most likely that. They are prone to crack. I now have a billet converter.
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God, I hope you are wrong. The leaking seems to have coincided with the weather turning cold though, so I don't know if that means something.

I really don't want to have to drop the tranny.
 
ashman said:
I don't think that is it. It's the same pattern it's been leaking for a few weeks now.


God, I hope you are wrong. The leaking seems to have coincided with the weather turning cold though, so I don't know if that means something.

I really don't want to have to drop the tranny.
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Mine cracked in winter too. Left a steady drip/ puddle in the snow.
 
Take a pressure washer and wash the trans really well, or get a big towel and just towel up the pan and surrounding wet areas the best you can. Then watch it while it runs and see if you can find the source. Is there an inspection cover you can take off to look at the converter to see if it's wet?

This trans was rebuilt by the P.O. right? IIRC

A name brand converter like Suncoast or ATS is going to cost you $1200 for the converter alone. Labor should be around $400 approx and plus fluid. You'll be over $2K out of pocket until you get your old converter shipped back and your core fee returned to you. There are also non name brand converters that can be had for cheaper too. You'd have to consult with a trans shop on what they can get. Even Trans Star makes a billet converter IIRC. PDQ is a good converter that is high quality and billet like the big names, but even they are over a grand now.

Nothing says you can't just put a new "stock" converter in it either. It would probably last as long as you'll have that truck anyway. I don't even recall that you have a chip or programmer in this truck, billet 3 disk converters are really kinda over kill on a stock truck anyway.
 
Thanks, that's what I'm thinking. I paid 6k for the truck, no chip. No reason to put high dollar parts in.
Also thinking about doing the labor myself. I have a shop and transmission jack. Can't be too hard... right?
 
ashman said:
Thanks, that's what I'm thinking. I paid 6k for the truck, no chip. No reason to put high dollar parts in.
Also thinking about doing the labor myself. I have a shop and transmission jack. Can't be too hard... right?
Click to expand...


Was the pump rub mod done to the tcase? If not good time to do it.
 
rjfguitar said:
Have you confirmed the source of the leak?
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Not yet. I plan on dealing with it this weekend most likely.

max 02 said:
Crappy part is that you would have to take the case apart to find out if has been upgraded or not.
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True, but if I have to take it out anyway, pulling it apart wouldn't take much time.
 
True... the bearing release is the hardest part the rest is easy.
Even that isn't hard with the right pliers.

Still hoping it's not the converter and you don't have the pull the trans. :popcorn:
 
inspected it a bit more today. It appears to be leaking from the DS back corner of the pan... but it could be running down the edge of the pan and just dropping there. Gotta look more closely tomorrow.
 
Seems as though I've gotten lucky on this leak too. Fairly certain it's just the pan gasket leaking.

I got under it a few days ago and wiped everything off real good so that I could see where the leak was coming from. After watching it a few days it was pretty obvious it wasn't coming from the bell housing area, so no cracked torque converter. The passenger side of the transmission was basically dry and I found a few pan bolts on the drivers side that were a little loose.

I tightened those up and kept an eye on it for a few more days. The leak is dramatically less, but it still seeps a bit, so I bought a filter kit and will be replacing the filter and gasket today, and torquing the pan bolts. Hopefully that solves my problem.
 
Well, it's been a few weeks and still no transmission leak. Looks like I got pretty lucky.

Of course, getting this lucky got me thinking about the oil leak. The truck has a very small oil leak. Nothing to worry about other than it staining my driveway. I assumed it was a rear main seal leak, and being as small as it is, no way worth pulling the engine to fix it. But, after crawling around under there, I'm starting to think it MIGHT be a pan gasket leak too. There is some RTV on various pieces under there that make it look like the oil pan was replaced sloppily at some point, leading me to think this is fairly likely.

Also, it looks like the duramax oil pan is pretty small and sits mostly only behind the engine crossmember. I think I could remove it without pulling the engine, but not positive.

Anybody got any experience doing it?
 
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