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What to do with a TH200-4R while it's out?

14K views 77 replies 12 participants last post by  TrannyMike 
#1 ·
I recently got a TH200-4R to replace the TH350. While I've got it out - and while I've got all winter to toy with it - what should I do?

I don't know much about trannys so I'm not sure where to start. Should I just go with a pan gasket & filter kit, seal kit and new bolts for the torque converter? It's a stock tranny (not a Grand National) going into a stock 350 motor. The pan looks pretty rough so I'll try and beat that back into shape. Should I replace the governor with a GN item?

And I'm not sure what to do with the lockup, either. :) I'll probably just start with a switch on the dash but I'd like to go for a vacuum-operated system eventually.
 
#9 ·
If this trans is known to work well do this. First pull the pan to be sure there is no excessive metal or any band or clutch material. A trans can work well even if something is just beginning to deteriorate. If it's good I'd install new front and rear seals, and a filter kit. If you can, replace the linkage seal too. There is a special tool for that, but you don't need it with the trans out. You would have to disassemble the linkage to replace it without the tool I mentioned. But since you say you have time to tinker with it, just be careful and do it the old fashioned way.

Now if your motor is stock you can install it as is. If you like firm shifts you can install a shift kit. The simplest one for a novice that's still very good is the Fairbanks stage 1 kit. That's how I'd go at this if I was you. If you need more detailed instructions message me. :beer:
 
#10 ·
I did forget an important detail. The cable will be different, so you'll need one for a 2004R. The carb linkage will need to be modified to correct the geometry and work with a 2004R. Message me about that if you need advice or need to know where to get the kit for that. Jegs sells them. There are other changes to convert it, but I'm not sure how much you already know about this. If you are completely clueless about the conversion then we'll have to have a longer conversation about this. Let me know. :beer:
 
#12 ·
I'm not a big fan of universal cables, but in this case it probably is your best bet. The 2004R's all had lock-up converters. If it's got round pads for converter bolts then it's a lock-up converter. If they are square or rectangle then it's wrong for sure. :beer:
 
#14 ·
As I've mentioned previously, I recently picked up a TH200-4R in order to swap in & replace the TH350 I've got. I picked it up from Craigslist from a local guy and it was gross.

Anyway, I got off my a** and went down to the local car-wash place in order to clean up the new transmission & torque converter. Discovered some things along the way, but as I've said previously I'm pretty clueless when it comes to auto trannys.

Here are some pictures of the tranny when I started. Eww!




One thing I can't figure out is there seems to be a hard, white plastic line that runs down the "spine" of the tranny. I tugged on it a little and it didn't move. What could it be?



Cast into the main part of the bellhousing is what looks to be "403" on one line and "X" just below it:



The internals under the cover of the bellhousing look pretty good:



Here is the tranny from the side. I was kind of shocked to see such a large dipstick tube! I'm actually not sure what this black cable is (pictured), but either way it's been cut. I presume that the two brass inlets/outlets (which have been cut, too) are for the tranny cooler.



Here's the serial number tag. I haven't deciphered it, yet:



Not sure what this serial number represents. It appears to be 8634005:



I presume this is the speedo cable, which has been cut. Not sure what the little nipple is farther up the trans:



On the other side of the tranny is a yoke (presumably for the shifter), a 4-pin connector with 3 pins inside it (presumably for the torque converter lock-up), and a plastic tab (I have NFI):



Here is the front of the torque converter. I hope this is the lockup kind! TrannyMike, what do you think?



The side of the torque converter. It looks like the PO has snapped off one of the studs, tried to cut it off, and then tried to cut the actual mounting ear off!



The back of the torque converter.

 
#15 ·
the cut off cable on the passengers side is the cable that goes to the carb, you'll need to replace that.

The little white tube on top is a breather, be glad you didn't pull it off/out.

You also lucked out, because that trans has the dual bolt pattern bellhousing. It will fit Chev and Buick/Olds/Pontiac engines.

on drivers side, you have those things figured out, except I don't know what the nipple is either.

what is that Mike?

the round mounts tell you that the converter is a lock-up model.

The dipstick tube necks down as it goes into the trans.
 
#17 ·
That pin holds in place a larger machined pin that holds the parking pawl.

I looked at your pics and you do have a problem. Look closely at the shafts coming out of the pump at the front of trans. Now look at the splines of the outer shaft. Those splines are bad. You can see 1 good spline in this pic. They should all be as thick as the one I mentioned. That part is the stator shaft.

When I made the 2004R HD parts list, which is a sticky, I mention replacing that stator shaft during a rebuild with a heat treated version because of what you see here. The new shafts don't do that.

In my opinion you should either get another trans or rebuild this one. You could just pull the pump and replace the stator if you have the tools to do it, but I bet there is more than just worn stator splines once you get into the inside. Sorry.:dontknow:
 
#18 ·
Mike I think I see what you mean. Let me go and take another pic of the shaft so we can make sure it's not an optical illusion :neutral:

If it does need replacement, what is a ballpark price for a shop to do it? $10, $100, $1000? If I don't replace the shaft, what will happen? I paid $50 for the trans, converter and flywheel so it's not a big deal if I have to scrap it but I'm curious to hear what my options are.

I read through the sticky thread and it looks like a heat-treated shaft is only $15 from bulkpart.com.
 
#21 ·
Thanks Mike, I'll definitely keep voting :nanawrench:

Is there anything else I should look for? I'm planning on pulling the pan tomorrow to have a look-see. So if I have the choice, should I get an genuine GM TV cable? Also what do you think that (vacuum?) nipple is for?

Check is definitely in the mail ;)
 
#22 ·
1st I already told you what that nipple is for. Now you made me say the word nipple again. I don't like saying the word nipple, it makes me feel dirty to say nipple. So please please don't make me say nipple again.

That isn't a nipple it's a roll pin that holds a larger machined pin in place which also holds your parking pawl in place.

Let us know what you find in the pan. There will always be some metal, but it shouldn't be excessive. You don't want to see any friction material at all. About the cable... what kind of carb do you have? Take a pic when you pull the pan and I'll advise you. :beer:
 
#26 ·
What type of carb are you running? The reason I ask is because of the different cable styles, and that it connects to the carb. The one pictured is the preferred type if it will work with your carb. The governor is inside the pan next to the valve body. You don't need to mess with that for now. :beer:
 
#28 ·
OK that's good. In that case the cable you showed last should work. Now there is one more thing. Since you had a 350 trans in it before, you may need a linkage adapter to give the correct geometry of the lever on the side of the carb. That can be dealt with after the trans is installed. We will have to see how it shifts with what you have now and go from there. :beer:
 
#29 ·
Word to the wise: do not attempt to get a tranny on an engine stand with no one to help you. It is... not the easiest thing in the world! Anyway, I got the pan off. Here are the pics. Bear in mind that I know practically nothing about transmissions (as this was the first time I'd seen the inside of one), but the first thing that popped into my head was "This is really pretty clean inside". Without further ado...

Off comes the pan. It doesn't look like it's ever been off before:



The back of the tranny:



The middle:



The front:



The stator:



The pan:



I'm not sure what this piece of metal is:



It was really hard to photograph the debris that was in the pan. They were like grains of sand, but maybe smaller and definitely softer. Friction material?



That's it. Let me know if you want to see a close-up of anything!
 
#30 ·
I hate to tell you this, but that's not sand it's friction material. I warned you that you might find more inside the trans. When splines are worn as badly as yours, there are usually a heck of a lot of miles on it. I'd call around for rebuild prices or you already said you found a shop, ask them. These trannys aren't cheap to do even though it's older. They are time consuming and in this industry labor is the more expensive part of any job. Sorry & good luck. :beer:
 
#32 ·
No it's not trash, rebuild it or have it rebuilt. If you think you're gonna find a cherry trans that's used from that era, you'd have to get lucky. What you see is normal for a trans that old. If you are keeping this car then do it right and do it once and then forget about it. That's my opinion. :beer:
 
#33 · (Edited)
Thanks Mike! I am interested in rebuilding it myself, but of course I don't have any of the specialty tools. I can get the repair guides & DVDs easily enough but it looks like the tools are prohibitively expensive for the amateur. A pump removal tool is like $80..

I guess I should relax given that the Elky still has a working TH350 in it! I only wanted the four-speed just for, well, the extra gear :)

I'll try and see if one of the local tranny shops will teach me how to do the work if I pay them for some of the labor, but I won't hold my breath.
 
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