Soooo here recently I have been having my share of issues with rebuilds. Some of which have seen me removing and installing transmissions up to a record of six times. Just to diagnose a tcc problem that really I only kinda understand. Now, supposedly, one could test an assembled pump body, input shaft/drum with a torque converter installed and test the hydraulic integrity of the circuit. I’m not sure but I am going to start by cutting the pump porting of an old case off of the rest of the case body and building a test rig. Or attempting to while fixing my mistakes and trying to keep the lights on and the family fed. Wish me luck fellas and any suggestions are welcome.

 

So is it a TC problem or trans?

 

sometimes it has has been the converter. Sometimes a pump valve issue. Sometimes I only think I know why the issue was resolved. What I want to do is make a rig that I can for certain know what parts work before I install the transmission the first time. That way if it doesn’t work, it can only be what wasn’t tested.

 

Sounds like an interesting project. It sounds like it should be similar to a dyno, but then it would be so nice to have most of the parts exposed, for not just checking hydraulics, but to see any problem areas. Almost similar to an operating transmission cutaway of sorts.
It would need a decent frame work to support torque converters, and it would be beneficial to have a way to add rotational input to the TCC, wouldn't need to be a huge amount of power.
But then its me, if there is an easy way to do something, I'll always find the most difficult one.

 

I am hoping that this rig would or could be used as a simple air check deal with no need for power application but I’m not opposed to seeking out better ways. Keep the ideas coming

 

I feel for you, over the years I have found that TCC issues can be a pain. Luckily when you cover all the bases they usually no problem with the common fixed . SONNAX TCC VALVE (Just as you learned previously make sure it does not over stroke) This is something I learned in the early days of those valves, The converter regulator valve and cap (The end cap is often overlooked and the source of a large leak ) and making sure the orifice is clear and solenoid functional.
But I have seen some baffling things with the DYNO every so often sometimes with solutions sometimes not.
Pump half leaks or cross leaks can come into play and the lockup function itself is more complicated than many think, I tried at one time to explain to a former employer wondering why it was taking so long to solve an issue that unlike gear clutch applies , it is not as simple as a piston applies and springs release. You are working with an apply and a release side hydraulically and can have issues from either. And of course with PWM LOCKUP also spends time between not fully applied or released.
Even with issue with the valve travel and shimming. You cannot do it for all as it may cause issues and you cannot do it with same shims everytime some require a little more some a little less and too much either way you again have a problem. And the spring must go through the shim else that to can be an issue.
Of course when I tried to explain they didn't understand much more than a simple on off apply piston is involved which is why chasing an off lockup issue can feel like chasing your tail at times. Can be very frustrating. I will be curious how your rig works out.

 

Torque converters ! My 1st Automatic trans was a cast iron power glide, then a few other of those nice 1950's cast iron boxes. The thing I miss is those nice bolt together torque converters, when they needed to be cleaned and checked and all ya needed was a new o-ring. Not a $200. take it and have it done deal. And you knew what was going in it and how clean or not it was. Yeah the welded ones were done for cost and I suppose leaks, I don't like them. Nice to see places like TCI making bolt together converters.
With bolt together at least you would know what is going on inside with the input shaft etc.

 

So this is a kinda proof of potential concept. Let me know your thoughts

 

Just a few questions. Since the stator support and input shaft are installed much farther than they would be when the trans is mounted on the engine, does that affect anything? Maybe a spacer should be used?
Do the 4L60E's use an apply and release side to the TCC piston? Seems like a good test for the TCC internal components, input o-ring, etc. If it was a new unfilled TC I wonder if a vacuum test would show anything? It would tell more than just blowing air.

 

great questions. I will answer with the “as I understand it” knowledge that I have. Which isn’t the most but it’s something.
1. So far in my testing, the depth of the input shaft and stator did not have an effect until the oring was out of it’s sealing bore.
2. Yes there is a pressure release and then a pressure apply. The pressure apply flows down the input shaft and out around the stator. That’s the hissing.
3. Yes this works on unfilled new converters. I do this with every converter now.
4. I don’t know how one would go about a vacuum test. The fluid for apply and release is also lube flow for the case and charge flow for the converter. The converter alone would hold 4 quarts of fluid so that is a ton of volume for a vacuum pump.
Just blowing air is my best/cleanest way to simulate the volume of flow if not perfectly the pressure and sealing aspect of a liquid. Hope that answers some of the questions.

 

Fascinating, I have never worked on a converter test rig but always wondered why converter manufacturers haven, They always want you to put oil in to soak the clutch and bearings yet seems like since the actual function of the converter itself is pretty simple for lockup a 1 size fits all test machine for a GM converter seem like would not be to bad to create and some the fill and function idea, I would not expect small shops to have such , But you would think the big players would?
Or perhaps they feel the converter it self is to simple for such a need?
Now the trans side is pretty complicated when dealing with apply and release sides either of which can cause issues to the other even in an on off style set up and even more so with PWM which uses both sides at once to meter slip.
But I like your set up and will watch as it progresses. Converter issues a failure have always been a scourge for trans builders.
I once spent days trying to figure out why on the dyno where i worked some would have lockup other did not and it was frustrating only to ultimately find it was the converter causing the issue. It was a converter we had used for years, But we learned above a certain line pressure it would just dump the lockup oil. Seems though over time and many test runs the apply plate had warped .
Luckily though with lockup most issues are easy fixes, Like the hyper travel valve we add shim to at times, Easy to fix but figuring out what they are first is the hard part.
Then VB wise issue none talk about like everyone mentions the ISO valve side of the converter regulator valve and while yes they do wear and leak and much larger leak almost always exist at the cap side of the valve and If you look at the diagram you can see how this would effect both ends of the valve and function.

 

This is what I have done when installing a converter. I will pour in a quart or so of the proper fluid, then move the converter all around like I'm coating all the insides, then I flip in over and drain into a nice clean bucket or what ever. So it will not drip or flood the bell housing when I install it.
I most always install a converter straight down and have the tail down and bell housing up. I've had bearing and seal issues doing it horizontal, and yes being super careful when installing. It just seems so much easier for everything to properly engage doing it my way. Sorta like installing OD splined parts into the multi disk clutch packs, you wouldn't want to do that horizontally.
The big problem with torque converters is your at the mercy of what ever trainee or technician puts it together, and how happy that person is with his employer that day.