Turbo 350 Disassembly

[HotRodPC]

Have you ever tried using like a flat bar on the belhousing with the spinners on the outside of that?

The clutch pack is cool, it looks exactly like a motorcycle clutch and also the same design is used by Caterpillar for the breaks on their haul trucks.

I don't think I understand the question. I have only done it the way I have pictured because it works well and has alwasy worked for me until this idiot used RTV to glue the damn pump in the case which is not needed. No reason to use RTV on a transmission at all, unless you want to use it on the pan gasket which I have never done either, but I have seen that done before after a trans service to hold the gasket in place while putting the pan back on.

 

[HotRodPC]

Now I pull the direct and forward clutch drums out as an assembly.

DOH !!! And to my suprise, we have broken parts and carnage !!! Not really !!! I expected to find this. I knew what was wrong with this transmission when I bought it. The input shaft was spinning with no resistance at all.

That told me the transmission had the 2nd most common failure of the Turbo 350. Broken input shaft and/or forward clutch drum where it mated to the input shaft, and sure enough I was right.

 

[Irishman999]

I don't think I understand the question. I have only done it the way I have pictured because it works well and has alwasy worked for me until this idiot used RTV to glue the damn pump in the case which is not needed. No reason to use RTV on a transmission at all, unless you want to use it on the pan gasket which I have never done either, but I have seen that done before after a trans service to hold the gasket in place while putting the pan back on.

I drew a picture, if this makes any sense.

You must be registered for see images attach

 

[HotRodPC]

Now we are looking at the Front Planetary Ring gear insdie the sunshell. This will slide off by hand and remove it from the case.

Now we see the Front Planetary Gear Set along with another piece of the broken forward clutch drum. Very hard to see, but there is a small snap ring that holds that planetary to the output shaft. The snapring it about as big around as a quarter and its insdie the recess of the planet gearset, so its a real bitch to get off. I use 2 small screwdrivers and a pick to get it off. I say its unlikley you'd be able to get a pair of snap ring pliers inside the recess.

 

[HotRodPC]

Now with the snapring removed, I can pull the front planetary gearset off the sungear.

And can also remove the Sunshell and sungear as a 1 piece assembly.

 

[HotRodPC]

I drew a picture, if this makes any sense.

You must be registered for see images attach

OK, so what you are saying then, is use some form or flat steel or even wood across the front of the bellhousing putting the allthread thru that, then tighten down the spinner nuts and use it as a puller. As you tighten the spinners it would pull the pump out of its case. I could do that, but I have never had to do so. It would work just fine though. I'd probably have to use longer allthread too. But, you get the idea. And you see, many of these "special tools" needed, can be improvised with and done without. Then of course, there are a few that just make sense to get becasue of the time and frustration they save. As you can tell, why do I need dent pullers to get a pump off? I've done many many transmissions with those pieces of allthread.

 

[HotRodPC]

Now we are looking at the front side of the low/reverse clutch pack pressure plate and rear plantaries. I will pull the big snap ring out of the case, then I can grab the output shaft, and start pulling on it, to get the pressure plate to come out of the case after I remove the anti clunk spring.

After pulling on the output shaft, the rear plantetary gearset, and low/reverse clutch pack come out of the case. You will also notice one of the several thrust washers hanging on the front of the output shaft. Some thrurst washers are plastic type, and some are metal or brass type. Also sometimes torrington bearings are used in place of thrust washers. Thrust washers are what keeps parts from rubbing and grinding metal to metal giving a surface to ride on and against. Thrust washers are also important for keeping tolerances where they need to be.

 

[HotRodPC]

After removing all of that. You might think you are done. But NO !!! What is left if the low/reverse apply piston.

This is where a special tool is required. Some builders will leave that piston in the case and start their build. Sure you can do it. But you are taking a risk because there are 3 square cut seals on that piston that may be dried out or hardened. Also if you take the case to be cleaned at a machine shop, those seals are now fried and for certain are no good. So if you want to chance it, do NOT take the case to be cleaned at the machine shop. Before I bought my special tool, I did make my own that worked OK. It had to do with a long bolt, and bent bracket, and I ran it thru the back of the case, with a large washer on it and a nut. As I tightened the nut, it compressed the springs but it didn't give me much room to get the snap ring out. So it worked, but it was very time consuming.

Once you have the snap ring taken out of its groove, you can release the tool and pull it out of the case, along with the springs and springs retainer.

 

[HotRodPC]

Now the case is empty and completely disassembled and ready to go to the machine shop for a bath if you wish, or spray it down with some oven cleaner and take it to a high pressure car wash. All depends on how clean you want it, and how dirty it is. Do keep in mind, or reassembly, it is very critical to keep it clean.

Here you can see the 3 seals I was referring to. If these seals do not work, then you will not have manual 1st gear or reverse in your transmission, so they are quite important.

Although a poor pic, here is what the spring cage assembly looks like that holds the low/reverse clutch piston in place. These are the springs you are compressing with the special tool so you can remove the snap ring. This is one style. Another style is all the springs are seperate pieces with a flat ring that goes over the top of the springs. So when you take it out, you 1 flat ring, and about 20 loose springs that tend to go everywhere. Just like with anything, even the same trans model can have differant designs in parts depending on applications for use, or year model changes etc. Its always important to know what will interchange with what.

 

[HotRodPC]

Here is what the output shaft looks like in a 2WD short shaft unit. It still has the rear ring gear attatched to it. Really no reason to remove it from the shaft unless you intend to change the shaft to a 9in shaft for a SB trans, or maybe you want to change out to a 4x4 output shaft. That would be the only real reasons to need to remove the ring gear from the shaft. Of course if the shaft was damaged and needed replaced, you'd also want to remove it from the ring gear and transfer the ring gear to the new shaft.

You'll notice the torrington bearing on the back of the ring gear riding on the output shaft. That is a selective bearing. Meaning it comes in differant thicknesses. You will select the correct size thickness to give you the correct tolerance in end play of your output shaft. Very rarely do you need to change that, but its a very critical step in your transmissions longevity.

 

[HotRodPC]

Now to remove the rest of the manual valve linkage, which is pretty straight forward and easy to do. I don't think anyone would need pics for that. But after that, this one is ready for the machine shop to be cleaned. My machine shop usually charges me $20 to clean a case. Many times I can get them plenty clean at the car wash for about $2 and I don't have to wait 2 days to start building it if I do that.

So, stay tuned for the buld!!!! I am not yet sure yet, if I'll start another thread for the build, or if I'll just add to this thread. But is now after 6am and time for bed !!!

 

[oneluckypops]

Pretty good man pretty goo. If you dont mind I will add a few things.

First the pump, Hotrod used 2 3/8" allthread and some other stuff to pull these, I find it is simpler to simply take 2 3/8" Bolts and screw them in the same holes as PUSHER bolts. I have always done it this way with minimal effort, and I have NOT damaged any of the cases yet.

Second. It might help others if you can do your fancy arrows on the valve body side of the case To show where you can use compressed air to remove the LOW/Reverse piston. And I know this is build part but the same Whole you can use to air test the Low/Reverse clutch.

 

[davbell22602]

 

[89Suburban]

Very well written Hotrod, and great points and additional tips from others here. I love it and read every word, but still can't comprehend all of it and am very intimidated by all these parts. Engine parts I am fine, but transmissions, it's a bit much for my brain.

 

[oneluckypops]

Very well written Hotrod, and great points and additional tips from others here. I love it and read every word, but still can't comprehend all of it and am very intimidated by all these parts. Engine parts I am fine, but transmissions, it's a bit much for my brain.

Sorry to Hijack Hotrod please delete if you want.
I would reccomend to youto Find an Old TH350 And completely tear it down, DO NOT BUY ANY New Parts for it just yet.

After you get it torn down completely reverse the procedure and put it ALL back togather, Do that a few times till you think you have it figured out.

Once you get your "own" technique for installing the Lip seals and you feel confident in Dis assembly and reassambly go ahead and actually REbBUILD it.

Oh yea it would also help you to have an ATSG book handy