Can anyone tell me what a CH F code 2004R came out of? Would it be a good core to build with this code? Thanks I also found one with a KJ F code but it had got rained in a good bit.

 

Valve body
Governor
Servo

those are the big things that make 2004r's special from one another

If you'll be rebuilding this, for any type of performance, you'll likely be installing a billet servo, calibrating the valve body, and using weights and springs to adjust the governor

All these 2004r cores are getting old and need alot of parts. Especially if you want them to hold decent power. I'd say the condition of the core nowadays is worth more than the code on the tag. just my $0.02

 

I actually know these transmissions quite well (and used to specialize in them... not many people use them any more).

The CH Trans. would be from a Monte Carlo 4.3L V6... (this is not considered to be one of the performance valve-bodies, and should not be used).

The KJ Trans. would be from a Cutlass 5.0L V8... (also not a performance valve-body, but better than the CH).

The valve-bodies for the THM200-4R vary/ differ a good amount (unlike a 4L60E or 4L80E).
The performance valve-bodies to be used are: BR, BQ, CQ, CZ, KZ, OZ, and TT.
And even the performance valve-bodies will need a lot of work/ improvement with aftermarket improvements.

A governor can be modified for any RPM desired... or swap one from another trans.
Pretty much none of the stock servos are good for actual HP...
The GN servo (scarce now) is good for 400+ HP.
Aftermarket larger servos are the only way to go.

The CZ performance valve-bodies are probably the easiest to find.
Get any good core that you can find and use it with one of the performance valve-bodies.

If you are not the type that like to research this kind of stuff yourself...
Than you can talk to Jake's Performance for a complete trans. or CK Performance for parts.

 

Thanks for the info and advice! 👍

 

You're welcome.

Good luck and have fun!

 

For the average DIY guy that just wants a simple vb with a code they know will leave them happy...i suppose you could be right

But for someone willing to spend some time, in your experience, what about the "performance" valve body is different enough to use vs a "bad" vb that is not to be used?
Just thinking through some of what I do on most 2004r's:
-Line bias will get blocked on any
-accumulator lineup will vary but not a huge deal...easy to swap spring or even sleeve/valve to get desired shift timing/feel
-Most builders will effectively bypass the tv limit (I'm sure you know the same way I know to produce fixed or semi-fixed [meaning idle won't be max but will be about 50% of typical line rise] line pressure)
-MTV up spring gets tossed just like a 700 to allow gear command
- The 3-2 valve should get blocked
-All that's left is the shift valves---With the governor you can get your shift points where you want them. And if you want to fine-tune each gear independently, you can get creative with the springs in the lineups to get it to do what you want.

The 1-2 accumulator spring setup isn't tough to figure out and adjust if needed
3-4 accum should get blocked


What is there that I'm missing that should make me want to throw those poor crappy factory vb's away?

p.s. like normal...I'm not talking crap, just trying to learn from someone I know has more 2004r experience than myself

 

The THM200-4R valve-bodies have many small differences between the different models/ Hydra-Matic codes.
Even the valve-bodies that have been deemed "Performance Valve-Bodies" are different from one another (just in fewer ways).
This is drastically different compared to a 4L60E or 4L80E.

All later production models have fewer differences than earlier production models.
As you already know separator-plates, governors, servos, and accumulators all differ among the different models; and can be interchanged.

Some of the differences are important... Many are not! (Power-Level makes these small differences even more important.
The valve-train for the shift-valves as a whole are better in the Performance VBs... but not the end of the world (especially if converter to a manual VB).
The 1-2, 2-3, and 3-4 Throttle Valves, Sleeves, and Springs can all be swapped from a Performance VB to a Non-Performance VB for better shifting consistency (but at that point, I would rather just use the Performance VB).

As power goes up the demand for fine-tuned hydraulics also goes up.
Shift timing and consistency, Line Pressure and consistency, Line rise and recovery are all crucial!
Shift timing issues, erratic shifts/ searching between gears, line-rise fluctuation, and 2-3 shift hunting are the more prominent issues with the "Non-Performance" valve-bodies (some of which is correctable to varying extents).

Just as we are all aware that the Accumulator valves used vary in the valve-land dimensions (length,diameter, and placement)... so do several other valves in the valve-body.
What is great about the accumulator valves that are used... is that they install into an aluminum sleeve... and any accumulator valve can be swapped as long as its sleeve is also used.
The dimensions of the sleeve OD are all the same for all the valve-bodies.

Many of the other valves obviously do not use an aluminum sleeve and thus not interchangeable.
I really need to go back into my notes to be able to go over everything... I apologize, for now at least... I am not going into detail.
Some of these, I have no doubt that you are aware of, since similarities are common in other Units like the THM700-R4 (since some 700-R4 designs come from the 200-4R).
I use many aftermarket/ TransGo THM700-4R valve-train parts for the THM200-4R valve-bodies and pumps Etc...

I will at some point go through my Home-Made THM200-4R encyclopedia (about 700 pages) of collected info from GM-Engineering and my personal data... for more/ better details on this.

Here is the list of VB parts that differ (many of which have valve-land dimensions and placements that will not physically fit or seal in another model valve-body).
Most all springs can be inter-changed unlike many of the valves.
Components in RED text are interchangeable/ mostly interchangeable.

-Exhaust hole locations in the casting... some use cup-plugs that can be removed or added.
-Accumulator Valve and Sleeve
-Accumulator Valve Spring
-Three-Four Shift Valve
-Three-Four Throttle Valve and Sleeve
-Low/ 1st gear Detent Valve and Sleeve
-One-Two Throttle Valve and Sleeve
-One-Two Throttle Valve Spring
-Torque-Converter Clutch Apply Valve
-Torque-Converter Clutch Throttle Valve and Sleeve
-Torque-Converter Clutch Throttle Valve Spring
-Two-Three Shift Valve
-Two-Three Throttle Valve and Sleeve
-Two-Three Throttle Valve Spring
-Throttle Valve
-Throttle Valve Spring
-TV Plunger
-TV Sleeve
-TV Spring
-TV Limit Valve
-TV Limit Valve Spring
-Modulated TV Down-shift Valve
-Modulated TV Down-shift Valve Spring
-Modulated TV Up-shift Valve Spring
-Three-Two Control Valve Spring
-Line Bias Valve
-Line Bias Valve Spring

Using a Non-performance VB (with different valves) would require me to create all new recipes, and many different recipes at that!
Primarily some of the shift timing issues will not be corrected when using a Non-Performance VB.
The components in the Performance VBs that are not interchangeable are:

-Line Bias Valve (I do not like to block it, but i mod the circuit, and use different dual spring assortments to fine-tune) (as you said TV supply oil can be looped over to TV boost valve by blocking and making a few holes)
-Modulated TV Down-shift Valve (needed for proper and consistent shift timing)
-TV Limit Valve (my modifications to this circuit depend on land sizes of the valve in the Performance VBs) (detent shifts will be affected by making changes here)
-Throttle Valve (swapped for TransGo THM700-R4 valve and dual springs)
-Two-Three Shift Valve (needed for proper and consistent shift timing)
-Three-Four Shift Valve (not as critical as the Two-Three)

The circuits into and out of the 3-2 Control Valve get many changes with the valve blocked.

Anything else can be swapped if making your own recipes...
As said, many aftermarket parts for a 700-R4 are used... for example the Pressure Regulator Valve, and both Boost Valve assemblies that I used are 700-R4 aftermarket parts (along with a GM Pink Spring).
The TV systems that I use, is mostly TransGo 700-R4 parts directly swapped over.

The CZF valve-bodies have been plentiful as far as the Performance VBs go... Most of my modifications/ recipes are based on this or the BRF VBs.