TH350 debris - toast?

[rdonahe]

Hi All,

I'm new here and generally new to GMs. I bought a '79 Silverado w/182k miles, pretty sure original TH350 transmission. Drove home around 20 miles with no issues. In city, highway and stop & go traffic. Drove it some more around the neighborhood that day and transmission started slipping in all gears.

Shut truck off to give it a think, started it up again and transmission worked fine. At first I thought maybe that was a coincidence but the pattern continued for a few more test drives, each time the distance it would work well was less.

Trans had fresh fluid in it by the look of it on the dipstick and it was overfilled somewhat.

Pulled pan and here's what was lurking in there:

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Looks like clutch friction material. Here's how the filter looked:

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Sooo, I put a new filter on. Put 24 oz of Lucas Transmission Fix and filled the rest of the way with new ATF. I have put roughly 40 miles on it since buttoning it back up and trans shifts fine. Am I sitting on a failing transmission?

Thanks in advance,
-Roger

 

[1987 GMC Jimmy]

Well, every transmission's got an expiration date, but you're right about what it looks like. At least to me. Do you know if the transmission has lockup or is it just a regular 350? They introduced that in 1979, I believe. The lockup would help with trans temps if it has it. Another thing that would help is trans cooler. I think you did the right thing by getting all that junk out of there, but it's hard to stamp a timeframe on something like that. If it were me, and I was just gonna drive it around locally for now, I'd run it around like it is. If the money is a concern, I'd start saving up now so you can be ready for the rebuild. It won't be bad at all if you do the R&R yourself, but if a shop does it, it'll kinda jack up your price. It won't fail tomorrow, but when it fails will depend on how much you baby it, how hot it runs, and how much more material it ejects into the pan and sucks up into the filter. I wish I could tell you more, but I'd just run it like is and see how it treats you.

 

[HotRodPC]

Hard to tell for 100% certain, but it appears to be chunks of clutch material. That would make me think the transmission had gotten very hot at one time and cooked the clutches and/or seals. Good news is, it's been serviced before to have the good dacron filter in it, but if the clutches are cooked, they'll disinegrate in a short period of time. The truck may have sat for a very long time too. That's not good either. If it's got 182,000 miles and with that debris in it, I'd say you're going to be pulling that transmission very soon. Like maybe this weekend.

 

[74 Shortbed]

It's time to tear it down before it gets totally ruined..

 

[HotRodPC]

It's time to tear it down before it gets totally ruined..

That would be my opinion too.

 

[rdonahe]

It's time to tear it down before it gets totally ruined..

So reading between the lines here would be that continuing to drive it as is may cause more damage? Would the damage be from more clutch material coming loose and getting into the works?

 

[HotRodPC]

IMO, for the most part, the damage is done. Just don't want to grind up your thrust washers, sprags and roller clutches.

 

[SkinnyG]

Advantage: a TH350 is ~really~ cheap to rebuild.

 

[HotRodPC]

Yep, about the cheapest.

 

[74 Shortbed]

Still no reason to destroy it completely, and that's what will happen if it keeps being used, and that ain't all that cheap.

 

[rdonahe]

Thanks all for the quick feedback. I guess I need to look into that rebuild option...