Rebuilding a TH2004R. Is it possible....?

[supercrackerbox]

"

Point is WITH the correct tools it's not that much worse than a manual trans. No feeler gauges, pretty much the torque wrench suffices. True we started with a clean trans with all new clutches, etc. nothing visably worn. Much of the upgrades mentioned on this board are available from mainstream suppliers like Dacco. Some specialized tools are MANDATORY, second pair of hands help. You might be able to do it to stand up behind moderate power.

That makes me feel better. Haven't done one solo, but I have assisted on several manual rebuilds. I'm willing to try an auto. Maybe I'll practice on my Metric-200 first just to get a feel for it though. Besides, the engine swap will be the last phase of the restification, so the tranny only has to hold up to the stock 305 for the forseeable future . . .

Are these books and videos mentioned enough, or would a factory service manual be in order as well?

 

[McHaggis]

That makes me feel better. Haven't done one solo, but I have assisted on several manual rebuilds. I'm willing to try an auto. Maybe I'll practice on my Metric-200 first just to get a feel for it though. Besides, the engine swap will be the last phase of the restification, so the tranny only has to hold up to the stock 305 for the forseeable future . . .

Are these books and videos mentioned enough, or would a factory service manual be in order as well?

I've just bought a copy of the ATSG book off ebay as suggested. I'll be using this book for the basic rebuild techniques, etc, but I'm going to "team up" with one of the "experts" on here for parts and advise on the performance and VB modifications that are need to make this trans live.

I suggest you try this too as while the books are invaluable for the basics the "experts" years of experience is what will make the difference. That's why I started this thread in the first place.

I bet there's more than a few on here that have rebuilt TH400's with the info posted on this and other sites because suddenly we all know how to "MODIFY" them to make them work they way we need them too. Thanks to those that have taken the time to share this with us mortals!
Keep it coming!!!

 

[LOT]

Not an expert

The only tool I have bought is the low and reverse housing removal tool. Worth every penny. I use a LARGE flat screwdriver--a medium flat screwdriver with a slot ground into it--- feeler gauge---regulated compressed air---needle nose pliers---snap ring pliers---dial indicator--calipers--home made lipseal installer. Once you get your direct drum, forward drum and center support rebuilt, you can apply compressed (40 psi) to certain ports of the center support to apply direct and forward clutches---do it multiple times to push out any excess fluid then check clearance with feeler gage. If you can get one of CK's books I believe it explains all this. I'm still concerned about using just ANY VB. Maybe someone that has modded one other than a TR will be able to help.

 

[McHaggis]

I'm still concerned about using just ANY VB. Maybe someone that has modded one other than a TR will be able to help.

This has also been my main concern but I think any VB can be modified to perform well?

One of the "experts" could chip in to confirm this and maybe they'll also explain what needs to be done to a standard VB other than up-grading the servo?

 

[jakeshoe]

Ya know what,
I'm going to tell some tricks...

200-4R VB.

You DON'T need a BR, BQ, CZ, CQ, OZ, or other VB.
There are better options anyway.

You WILL spend some time working with governor calibrations to get desired shift points. I'll leave that to the motivated to learn like I did.

VB mods.

Drill the 2nd feed hole .093-.125" depending on servo, accum mods, etc.
Drill the 3rd feed .125-.140.
4th feed to .096 maximum.

Remove the line bias spring, install it in the accumulator valve.
Install a 700-R4 3-4 return spring in the line bias or otherwise block it.
Install a .500 boost valve, pink 700-R4 pressure regulator spring, and larger reverse boost valve.

Use a GN or billet servo.

I use commonly available 700-R4 accumulator springs for the 1-2 and 3-4 accum and calibration depends on the unit but usually I use white.

You will use 5 checkballs in the case.
Rule of thumb on a 200-4R. If it's a bathtub it gets a checkball always.
There are 4 in a line from front to rear. 2 small checkball locations and 2 bathtubs, install in the bathtubs, leave out of the small locations (3rd accum and 3-2 )

That's it. 600+ HP proven with dual feed and proper hard parts.

 

[McHaggis]

Ya know what,
I'm going to tell some tricks...

200-4R VB.

You DON'T need a BR, BQ, CZ, CQ, OZ, or other VB.
There are better options anyway.

You WILL spend some time working with governor calibrations to get desired shift points. I'll leave that to the motivated to learn like I did.

VB mods.

Drill the 2nd feed hole .093-.125" depending on servo, accum mods, etc.
Drill the 3rd feed .125-.140.
4th feed to .096 maximum.

Remove the line bias spring, install it in the accumulator valve.
Install a 700-R4 3-4 return spring in the line bias or otherwise block it.
Install a .500 boost valve, pink 700-R4 pressure regulator spring, and larger reverse boost valve.

Use a GN or billet servo.

I use commonly available 700-R4 accumulator springs for the 1-2 and 3-4 accum and calibration depends on the unit but usually I use white.

You will use 5 checkballs in the case.
Rule of thumb on a 200-4R. If it's a bathtub it gets a checkball always.
There are 4 in a line from front to rear. 2 small checkball locations and 2 bathtubs, install in the bathtubs, leave out of the small locations (3rd accum and 3-2 )

That's it. 600+ HP proven with dual feed and proper hard parts.

Information like that is priceless! Thanks Jake!

 

[LOT]

same here

I do the same thing on the line bias--remove and use in the accumulator--I block the line bias using a 1/8 in. roll pin ground down to .860 long. Have also drilled same holes bigger, but not that big. Thanks for the info.

 

[McHaggis]

The only tool I have bought is the low and reverse housing removal tool. Worth every penny.

I hate to sound stupid but what exactly is this? I'm currently not fimaliar with the TH2004r internals or how to pull them apart.

 

[SSedan64]

I hate to sound stupid but what exactly is this? I'm currently not fimaliar with the TH2004r internals or how to pull them apart.

Metal Low/Reverse Tool>> GM Lo-Reverse Clutch Remover Installer #2843: eBay Motors (item 170279815039 end time Sep-07-10 18:48:00 PDT)

I have one like these, Plastic>> j28542 items - Get great deals on Parts Accessories items on eBay Motors! but I think the metal one works better & is more durable.

If you search for Tools in the Trans section you'll find several threads with other tools also.

 

[McHaggis]

Metal Low/Reverse Tool>> GM Lo-Reverse Clutch Remover Installer #2843: eBay Motors (item 170279815039 end time Sep-07-10 18:48:00 PDT)

I have one like these, Plastic>> j28542 items - Get great deals on Parts Accessories items on eBay Motors! but I think the metal one works better & is more durable.

If you search for Tools in the Trans section you'll find several threads with other tools also.

Hey thanks for the links to ebay. Seeing a pic of the tool is great as I had no idea what one was.....and still don't! LOL.
Do you NEED to use one of these or can the clutch be removed by other means? I'm guessing it can, just not that easy?

 

[artsvettes]

Metal Low/Reverse Tool>> GM Lo-Reverse Clutch Remover Installer #2843: eBay Motors (item 170279815039 end time Sep-07-10 18:48:00 PDT)

I have one like these, Plastic>> j28542 items - Get great deals on Parts Accessories items on eBay Motors! but I think the metal one works better & is more durable.

If you search for Tools in the Trans section you'll find several threads with other tools also.

Either one works well I have both. Low/ Reverse cluthe is a pain to remove with out the tool.

 

[McHaggis]

OK. I've got the VB mostly sorted so I guess the next item is the pump. From reading all the stuff at the links provided (thanks SSedan64) the 10 vane is the way to go. The pump, and therefore oil supply/pressure, seems to be one of the most important bits to get right. Looking at the details in the sticky by Bruce this appears to be another area where black magic plays it's part. The detail that's listed in this thread is bewildering to say the least.

My question is: Can "I" successfully modify a standard used pump to the required level, should I buy a new one from GM and modify it, or is this one item that should be set-up by the pros?

 

[LOT]

pump

OK. I've got the VB mostly sorted so I guess the next item is the pump. From reading all the stuff at the links provided (thanks SSedan64) the 10 vane is the way to go. The pump, and therefore oil supply/pressure, seems to be one of the most important bits to get right. Looking at the details in the sticky by Bruce this appears to be another area where black magic plays it's part. The detail that's listed in this thread is bewildering to say the least.

My question is: Can "I" successfully modify a standard used pump to the required level, should I buy a new one from GM and modify it, or is this one item that should be set-up by the pros?

Assuming the vane pocket is not scored and you have outside and depth mics, I see no reason why the average person can't take a good used pump, drill the drain back hole--measure the rotor,slide and pocket--shoot for .001 clearance---run a flat hone over the pump halves--install .500 boost valve, .300 reverse boost and one of TCI 280 PSI pressure reg. spring --hardened stator tube along with a 10 vane kit. I'm sure it would be nice to be able to have a lathe to make sure the stator tube is true to the body. Not every builder has that ability. I could supply you with the TCI part # if you want. Best of luck

 

[turbo nasty]

10 vane pump will work but 7 is fine as well if yours is good.

Trans Go HI REV pump kit has some real nice pump rings and spring in the kit.

As stated make darn sure the pump halves arent scored the least bit.

Ultra important!!

In teh pump. as recommended a .500 boost valve is fine, I have used a .555ish (PTS rPSI reg kit) as well but its overkill IMO.

At a minimum get a billet forward drum and dual feed the directs and use a 6 clutch direct and thick steels.

How much power and weight is this going behind?

Good VB kit is the California Performance trans High tech valve body kit. The gil younger trans go one is just to much IMO

 

[McHaggis]

10 vane pump will work but 7 is fine as well if yours is good.

Trans Go HI REV pump kit has some real nice pump rings and spring in the kit.

As stated make darn sure the pump halves arent scored the least bit.

Ultra important!!

In teh pump. as recommended a .500 boost valve is fine, I have used a .555ish (PTS rPSI reg kit) as well but its overkill IMO.

At a minimum get a billet forward drum and dual feed the directs and use a 6 clutch direct and thick steels.

How much power and weight is this going behind?

Good VB kit is the California Performance trans High tech valve body kit. The gil younger trans go one is just to much IMO

Good info here. Thanks.
It's going behind a 450hp SBC (6700rpm max) in a 3100lb car.

 

[McHaggis]

Assuming the vane pocket is not scored and you have outside and depth mics, I see no reason why the average person can't take a good used pump, drill the drain back hole--measure the rotor,slide and pocket--shoot for .001 clearance---run a flat hone over the pump halves--install .500 boost valve, .300 reverse boost and one of TCI 280 PSI pressure reg. spring --hardened stator tube along with a 10 vane kit. I'm sure it would be nice to be able to have a lathe to make sure the stator tube is true to the body. Not every builder has that ability. I could supply you with the TCI part # if you want. Best of luck

Good info here too. I'm lucky as I have access to a lathe but what if the stator tube isn't true with the body?

 

[LOT]

I assume

Good info here too. I'm lucky as I have access to a lathe but what if the stator tube isn't true with the body?

You would chuck stator tube in lathe and shave pump face and back side. I have never done this, so maybe someone who has will give their input. My experince is limited.

 

[McHaggis]

You would chuck stator tube in lathe and shave pump face and back side. I have never done this, so maybe someone who has will give their input. My experince is limited.

I thought that might be the answer but how would this affect clearances?

 

[SSedan64]

Truing the Pump cover surface to the Stator wont effect Rotor & Slide clearance as they're in the Pump Body. If the Body pocket is scored & needs to be cut the face will have to be cut to correct Rotor & Slide clearance.

 

[LOT]

True

Truing the Pump cover surface to the Stator wont effect Rotor & Slide clearance as they're in the Pump Body. If the Body pocket is scored & needs to be cut the face will have to be cut to correct Rotor & Slide clearance.

pump is 2 halves--tube is in solid (flat) half--other half has the pocket.