Problem 200r4

1320chevy

Apprentice
Jun 23, 2023
51
39
18
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.
 
  • Sad
  • Like
Reactions: 1 users

1320chevy

Apprentice
Jun 23, 2023
51
39
18
Right... shift and nothing happens , then, a moment later it shifts, but sometimes it's one moment and sometimes it will hold on 'till the rpms are nearing 7k before ti shifts.
AND, same shifter and shift cable is in use now on different transmission and working perfectly. One thought: Around the second or third time the trans was sent back, one of the things it was doing aside from the persistent late shifting,was that while driving, the shift handle would suddenly be impossible to move at all 'till the engine was turned off. Extreme never told me what caused that but I suspect that the pressures they run are so high that it was pinning the spool valve against it' s bore . Pressure got so high that it ruined my pressure gauge, pinning it past 300psi.
 

pagrunt

Geezer
Sep 14, 2014
9,152
15,302
113
Elderton, Pa
Right... shift and nothing happens , then, a moment later it shifts, but sometimes it's one moment and sometimes it will hold on 'till the rpms are nearing 7k before ti shifts.

AND, same shifter and shift cable is in use now on different transmission and working perfectly. One thought: Around the second or third time the trans was sent back, one of the things it was doing aside from the persistent late shifting,was that while driving, the shift handle would suddenly be impossible to move at all 'till the engine was turned off. Extreme never told me what caused that but I suspect that the pressures they run are so high that it was pinning the spool valve against it' s bore . Pressure got so high that it ruined my pressure gauge, pinning it past 300psi.

I've never dug into any automatic but could it be possible that dispite using all the heavy duty & performance spec parts they never tried to match parts to ensure shift points are where they should. It's kinda like they mixed parts between the likes of an GN, 442, MCSS & base V6 just because they all fit in a TH200 4R case. I know myself things need to match for the desired performance/fuction in an automatic.
 
  • Like
Reactions: 1 users

64nailhead

Goat Herder
Dec 1, 2014
5,686
1
12,139
113
Upstate NY
Hmmm, that’s a new application for me.

I’d guess you have a linkage problem as well. But I’m not sure exactly what is going on in your manual valve body, but I’ve never been around one that didn’t shift at the same time the shifter is moved unless the converter is relatively loose.

How loose is the converter? How much power? Same gear change every time that the issue occurs or is it completely random? Does it ever not shift at low load situations?
 
Last edited:

64nailhead

Goat Herder
Dec 1, 2014
5,686
1
12,139
113
Upstate NY
AND, same shifter and shift cable is in use now on different transmission and working perfectly. One thought: Around the second or third time the trans was sent back, one of the things it was doing aside from the persistent late shifting,was that while driving, the shift handle would suddenly be impossible to move at all 'till the engine was turned off. Extreme never told me what caused that but I suspect that the pressures they run are so high that it was pinning the spool valve against it' s bore . Pressure got so high that it ruined my pressure gauge, pinning it past 300psi.
Same shifter and cable? Did you change the ‘gate’ in the shifter because a gate that works for a TH350 isn’t the same for a 200 or 700.

Line pressure is not your enemy with a 200-4R. It’s not a 400 or 80e. My son’s 200 makes 280 by design and it could be adjusted higher I’ve been told if the clutches couldn’t hold the power.
 
  • Like
Reactions: 1 users

ELCAM

Royal Smart Person
Jun 19, 2021
1,120
1,263
113
Stock GN 200-4R has over 300 Psi line pressure. All the other 200-4Rs can be diagnosed with a 300 Psi gauge.

Not sure what a BQ is, it also exceeds 300 Psi, though it might not destroy your gauge like the OZ.

200-4R Oil Pressures..png
 
Last edited:
  • Like
Reactions: 2 users

78Delta88

Royal Smart Person
Supporting Member
May 23, 2022
1,284
1
1,075
113
SW Arizona
If they did the billet corrections and heavy duty internals that's a start. The custom valve body is definitely suspect. It sound like they set it up for TV delete, but did not do what was necessary for it to work that way.

Not being a Race Car expert I question why they didn't go lockup. I would think lockup in forth would benefit you on the track.

Did they dyno it? Most reputable shops will dyno their work, for at a minimum not having you go through this. As a former shop owner I stay with in my limits, and to have a customer tell me they R&R the unit 7 times? Absolutely not!!!

Art Carr and McCleary are the experts when it comes to TH200 and 2004R, did they call them and try to find out why? Or just chuck you farley?
 
  • Like
Reactions: 1 user

spidereyes455

G-Body Guru
Mar 6, 2013
780
1,630
93
Northeastern PA
Interesting. Since if you talk to any serious turbo Buick guy they will tell you that Lonnie Dyeres (Extreme Automatics) is one of the premier builders of 200-4R's in the country. Alongside Dave Husek of turbo buick performance.
I was really expecting to hear this was a Monster transmissions build, cause the only people that have anything good to say about them are the car shows on cable that are sponsored by them.
 
  • Like
Reactions: 3 users

78Delta88

Royal Smart Person
Supporting Member
May 23, 2022
1,284
1
1,075
113
SW Arizona
Right... shift and nothing happens , then, a moment later it shifts, but sometimes it's one moment and sometimes it will hold on 'till the rpms are nearing 7k before it shifts.
Did they hand craft the main spool valve and did they set the governor? If this was just a regular trans I would be inclined to check governor for proper operation and in this case I think it should be locked. What power adder do you have? Are you running boost or nitrous, both? If 6500 is you shift point what is the HP there? What is the torque curve like at that point?

On the TH350 when you shift at (_______) where does your rpm drop? And how fast to recover to next shift point at (_______)?

The random shifting you experience is indicative of valve sticking in the valve body bore or accumulator piston sticking, cocked in the bore, or broken spring.

I'll dig into some of the books, because believe it or not..., I might be wrong. But every thing you mention tells me valve body issue. If loss is 2nd or 4th it's the band, but you mention no flare, so..., hmmmm.
 
Last edited:

81cutlass

Comic Book Super Hero
Feb 16, 2009
4,644
13,556
113
Western MN
Extreme Automatics is one of the known 2004r builders with generally a good reputation. Husek, CK, Art Carr, Lonnie are all people who seem to be decent. You hear more good than bad as long as you can get pats.

If you said you went to Monster or good boy's down the street I'd 100% believe you, but theres a few checks that you might need to do that might be lost in translation.

A common problem with trans installs is shifter location and fluid level. Have you checked those? The dip stick should be calibrated on a performance build (google search can show you what that process entails) and sometimes an aftermarket shifter can hang the selector in between gears. I had a friend who cooked a trans because as the chassis flexed under power it was shifting the trans between 2nd and 3rd. You want to make sure the shifter detents match the selector detents PERFECTLY
 
  • Like
Reactions: 1 user

GBodyForum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.

Please support GBodyForum Sponsors

Classic Truck Consoles Dixie Restoration Depot UMI Performance

Contact [email protected] for info on becoming a sponsor