Bought an "exotic build" 200r4 transmission for our G body (85 montecarlo). Unit has all the bells and whistles offered. Special pump, special clutches, all thrust washers replaced with rollers, many hard parts custom made from billet or heavily modified. Valve body is of this companies own design and is supposed to be based upon the best oem but with many "secret" modifications. Converter was supplied by the same company and is supposed to be around 3000 stall with no lockup feature. OK, the problem is that the unit has never worked properly but being patient, we kept sending it back in hopes that they would make it work. (unit has been in and out of the car over seven times and NEVER has worked right. SO, WHAT'S THE PROBLEM? Well, it has finally sunken in that the shop that created it, is in way over their heads and simply don't have the knowledge base to draw from to make it work. The main problem is, this is a race car. During competition, the driver makes a shift at lets say, 6500rpm. The transmission does not respond. It does not slip and the rpms do not flair but keep going up as if the next gear had never been selected. Then, at random, it will shift. This is unpredictable with regard to rpm but always happens. You simply cannot depend upon it for any kind of consistency.. Yes, fluid is full and is not ever burned. The shop contends that this is impossible and that we are just wrong. We took this unit out of service and replaced it with a th350 and the problem is gone. so, it's not us or the car. This unit has cost us over $4,000 and I'd really like to have it working.
Problem 200r4
- Thread starter 1320chevy
- Start date
It's a mid 11 second racecar,.... Driving in the pits, it shifts when its told. Converter has lockup deleted and supposed to be 3,000 rpm stall. It starts trying to overcome the brakes at around 26 hundred. All shifts are at between 5 and 6k depending upon weather and track conditions. It's unpredictable. Sometimes it nearly works and other times it acts like it's never going to shift at all.
I'd agree with you but I wouldn't be here asking if I hadn't checked over ALL the basics. Been in the auto business and racing since 1967. I build my own stuff but with a transmission, Though I could do the work, to do something that is a total departure from stock, I'd rather rely upon someone who does that every day. The guys at extreme are very nice people but at this point, they have run out of ideas and that leaves us with a unit that has NEVER worked properly from day one.
Many of the components are made in-house by extreme. Matching parts won't work because there is nothing to match them to. If this was a standard build, long ago, I would have pulled it apart and done it over. Being their design, nobody has a clue what they did inside it except for them.
From what you’ve described, there is an excellent chance that you’re encountering the converter coupling and uncoupling. The symptom is that the gear change is commanded, but the rpm’s don’t change - but it will still be accelerating despite no change in rpm’s. This is not an uncommon issue in drag racing. It’s easily seen in a datalog that identifies wheel speed vs. rpm change.
A way to test this would be to head the drag strip and make some runs to see what is happening with trap speed with varying shift rpm’s. Very easy to see if you can datalog, but I know that is a tall order with a manual shift 200.
As I mentioned initially, you application is not a typical automatic transmission build imho. I would guess this is why so many use a manual for autocross type events.
Edit : regarding datalogging. - line pressure, TPS and MAP along with speed and rpm would be prerequisites to make much of the information in the datalog.
Ehh, I disagree respectfully. Find yourself a true transmission guy that knows what he’s looking at. Those guys are hard to find. I’m fortunate that I found one that’s somewhat local - he tore apart my son’s stage 2 from CK Performance and knew exactly what he was looking at and he improved it. I can elaborate on some conversations I’ve had with my guy about our 200 and my 80e - the conversations are crazy (and funny). They always end without all of the details and ‘give it a try and let me know’ (which doesn’t make me warm and fuzzy).But whenever I tell him it works amazingly and better than before I get a response of ‘no kidding and be safe’. He knows his poop.
I did some diving last night, until the phone died, found this.
www.v8buick.com
Seems like you are not the only one. I'm not directly experienced with Extreme and I want to offer the benefit of the doubt, but something there isn't right. In this other case Lonnie offered to buy it back and that's honorable. Any good shop should do the same. I know if it were mine I would have offered the same, yet I would have also focused on finding the root cause and fixing it if possible.
My gut feeling, and this is only blue sky here, but I wonder if they didn't just add the TCI manual valve body (MVB)??
Transmissions can be kind of funky at times, and especially when changing from OEM to total custom work.
At the time 2004R rolled out it was at the beginning of our current EPA nightmare. You have to figure the 2004R would be in an Oldsmobile 98 4 Door Cabin Cruiser mated to a 307. Not anything that anyone would call "performance", but it increased MPG, and that's what the OEM needed, and that was why it was created.
On TH350 that is running good, did you change the TQ Converter?
2004r broke
I bought a stage 1 built 2004r and put it behind the 350 in my ‘72 GS about six years ago. When I swapped to a 455, I overtorqued the transmission and...
www.v8buick.com
Seems like you are not the only one. I'm not directly experienced with Extreme and I want to offer the benefit of the doubt, but something there isn't right. In this other case Lonnie offered to buy it back and that's honorable. Any good shop should do the same. I know if it were mine I would have offered the same, yet I would have also focused on finding the root cause and fixing it if possible.
My gut feeling, and this is only blue sky here, but I wonder if they didn't just add the TCI manual valve body (MVB)??
Transmissions can be kind of funky at times, and especially when changing from OEM to total custom work.
At the time 2004R rolled out it was at the beginning of our current EPA nightmare. You have to figure the 2004R would be in an Oldsmobile 98 4 Door Cabin Cruiser mated to a 307. Not anything that anyone would call "performance", but it increased MPG, and that's what the OEM needed, and that was why it was created.
On TH350 that is running good, did you change the TQ Converter?
I tend to agree with you about the converter. It almost seems like the sprag in the stator is grabbing at random times. Chris from Extreme told me that it is impossible, I actually considered getting a diode stator just to see if it would help. Datqaloggers are damn expensive but I see a lot of value there. nI really don't like putting a 350 behind our engine. It's a very torquy 383 and it likes leaving hard enough to lift the wheels. Very stressful to a driveline. I actually bought three 350"s just so I'd have a good supply of parts. I'd really like to make the 200 work though. I've invested a lot of $ and a ton of time into this ans can't even sell it to anyone . I can't sell junk.
I'm curious if issue isn't converter driven as well.
You mention coming into pits, it shifts on command, yet under load it's shifts are inconsistent. This could be fluid coupling issue and that is the converter.
You mention coming into pits, it shifts on command, yet under load it's shifts are inconsistent. This could be fluid coupling issue and that is the converter.
Exactly. He could be moving the shift lever and the trans is shifting but the rpm’s don’t drop - big power, small tire guys send their converters back (or have bolt together) to get them to respond in that manner.
Like I mentioned, a couple trips down a drag strip with some info would identify it in a hurry.
Steve Morris posted a video last night of the last day out with his wagon- it hangs at 8000 rpm’s through 3 gears and keeps accelerating.
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