I knew this trans was dead... TH350 Rebuild

[crazy4offroad]

Wet/dry clutches won't make a difference, and if worse comes to worse I think they make steels in selectable thicknesses to dial it in. Having the clutch pack too tight is what's hard to work with. It's hard to see 1/10" on a ruler. Once the trans is warmed up to 150-250F you'll be lucky to have 1/100" once everything made of steel expands.
And...
To err is human, to admit to it is effeminate.

 

[da_raabi]

Working on putting together the parts I need. I posted a "Wanted" post about the parts I'm looking for. If anyone has any of these parts stashed let me know.

http://www.gmsquarebody.com/threads/th350-parts.22331/

 

[da_raabi]

The retainer, I would just replace it. I might have one in my spare parts if you can't find one.

Would you mind taking a look for me? They seem to want an arm and a leg for this stuff on the fleabay, so anything you can help with would be awesome. I've got a wanted ad up too for some other odds and ends if you think you might have anything.

 

[crazy4offroad]

Been working 10s and 12s but just dug one out of my parts bucket and put it in the parts washer. I'll clean it up this weekend and let you know if it's any good. I'll check on the other things too.

 

[da_raabi]

Been working 10s and 12s but just dug one out of my parts bucket and put it in the parts washer. I'll clean it up this weekend and let you know if it's any good. I'll check on the other things too.

Yikes. 12s suck big time. OT is nice, but it sure comes at a price. Thanks for taking a look for me.

 

[crazy4offroad]

Cleaned up the rear planet today, looks like the holes may have been a factory thing, or we had the same guy mod them in the exact same way...

You must be registered for see images attach

This one was pretty rusty but i got most of it off and the gears didn't want to spin at first but they did loosen up. If yours is ok i would just run it if i were you.

 

[da_raabi]

Cleaned up the rear planet today, looks like the holes may have been a factory thing, or we had the same guy mod them in the exact same way...

You must be registered for see images attach

This one was pretty rusty but i got most of it off and the gears didn't want to spin at first but they did loosen up. If yours is ok i would just run it if i were you.

Hey thanks for looking at that. Mine seems ok. I did some clean up on it and other than the black junk from the clutches it seems ok.

Good to know on the holes too. Hopefully this will help someone else wondering about it. There was almost nothing on the subject on the net!

 

[da_raabi]

So... Is this going to be a problem? I found a bunch of metal shavings around this area during disassembly. There do not appear to be any high spots around these score marks, but I gave it a quick buff with some 0000 steel wool. You can feel the scores, but no ridges. Still usable?

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

 

[HotRodPC]

I'm trying to think what would actually cause that. It kinda looks like stress fractures and I just don't think I'd use it. I know I wouldn't being that I have other good ones, but I'm just trying to think if I were you and didn't have a spare laying around, would I use it or replace? Even still I think I'd replace that. Even if it's not a stress fracture, that groove may have tendency to pick you trash as it lubes, score the bushing and then the domino affects and **** starts getting tore up and the transmission is short lived after that. That come comes in a 2pc and a 1pc, and thrust washer model and a torington bearing model depending on the year. That appears to be a 2pc torington bearing unit.

 

[crazy4offroad]

Looks like a rear ring gear? Notice the bottom 3/4 inch or so looks heavily scored. Likely the torrington bearing disintegrated. I would inspect the output shaft as well.

 

[da_raabi]

Looks like a rear ring gear? Notice the bottom 3/4 inch or so looks heavily scored. Likely the torrington bearing disintegrated. I would inspect the output shaft as well.

Yeah, its the rear ring gear. I'm pretty sure it was the torrington that let go. I found lots of metal bits in that area when I pulled it all apart. This is probably why the trans had a HUGE amount of end play when I got it. So much so that the parking pawl would not engage because the carrier was so far back. I dunno what this previous builder did, but he sure did it wrong!

I guess I'll hold off on ordering a replacement ring gear until I find out if the output shaft is good or not. If its not then I may have to... divest myself of this project. The gear is only $45, but the shaft would probably be another $40. Of course this is after I've already got about $400 in parts into the thing... In the end the whole trans (if I had to get a new gear and shaft) would come to a little over $650 in parts (not counting original $150 purchase price). Assuming everything goes back together ok and I don't blow the rebuild that's still not bad for a upper-mid level th350 build.

Fuggen craigslist transmissions.

 

[HotRodPC]

It all makes sense now. So that's what caused the scoring. So that confirms t o me, NO, I would NOT use that part. As said even if you smoothed out any burrs, I'd think those grooves that are left would work like shovels and retain fine debris and start scoring the case bushing and cause premature wear. Hopefully I'll make it to the shop today. The drunk will sleep all day so I don't have to babysit him today. I'll see if I have that part too. Pretty sure I do. I'd think the output shaft is likely to be fine since it rides ID, not OD where the scoring was. What I would check though, is to make sure the rear of the case isn't chewed away where the inner part of that ring gear was slamming into the back of the case with excessive end play after the torrington exploded. I don't recall that being selective at the rear of the case in a Th350 like a Th400 is, so if it's chewed out a little you many not be able to make it up with a thicker selective thrust washer. I'll take a look.

 

[HotRodPC]

I'm going to try and make by the shop this trip out. I'll see about that part too.

 

[da_raabi]

As promised, here is some more carnage! I think I may have figured out the biggest mistake the previous builder made. Based on the marks in the case, and the below pictures of the output case bushing, I am thinking the builder forgot to pilot the bushing down a bit to clear the "ears" on the output torrington bearing! So the bearing essentially "ate" the bushing, creating quite the nasty mess.

Also found more scoring on the bushing surface of the front gear set.

So I went ahead and ordered rollerized versions of both gear sets. Hopefully that will be the last parts I need...

Well, except for the extra case bushing I had to order because I bent the new one trying to install it. Any tips on how to get that bugger down in there?

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

 

[da_raabi]

New case bushing is in. I ended up using a big-ass hub nut socket (backwards, teeth up) with about 2 feet of socket extensions as a driver to drive it flush, then used the bent new bushing (don't ask) to drive it down far enough to clear the new torrington bearing. I have no real way to check whether it was in straight or catty-whompas after that, but it looked good to me.

I put a little blue locktite on it too. The manual said Red, but I didn't have any. The container was red. Does that count? lol

Also got the low/reverse piston and spring cage (thanks again @HotRodPC ) installed. It went in WAY easier than it came out.



So I've got the case hanging from an engine hoist while I'm doing this. I'm wearing, not nice, but decent clothes at the time. Definitely NOT work clothes. I'm thinking, "nah I'm not doing anything dirty here. I'll be fine" I've got the valve body section facing me... The wife is supervising/helping right there with me...

See where this is going?

So I soak down the low/rev piston in fluid, as well as the bore of the case. Got it nice and wet to make sure it would slip in nice and easy... Wow. What a sentence. Anyway, I get the piston down as far as I can, so I grab a socket extension and a hammer and lightly hammer on it to get it fully seated.

What do you think happens next? SPLAT SPLAT SPLAT. Damn thing pisses tranny fluid all over my shorts, the wife starts yelling at me about ruining good clothes, and there I am giggling like a Japanese school girl, covered in tranny fluid. The wife yells at me to drop my shorts right there so she can get stain remover on them. I realize I'm wearing a decent shirt too, so off it comes. Now I'm working on the trans in the good 'ol trusty whitey tighties.

It was a sight to behold.

And that's my story.