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Discussion Starter · #21 ·
I totally share your opinion!

Of course, if a gunked up old, hydraulic trans gets flushed, there might be some rough shift after that. A friend of mine had a A 413, totally burnt fluid, never serviced. They flushed it, after that, shift quality was gone, before the flush it shifted very slowly, with a lot of slippage. After that, finally cleaned, it smashed in gears cause of proper fluid circulation, but the clutches and bands were already done.

But on the A 604, shift quality shouldn´t change in the whole life of the trans, if every sensor, solenoid etc. is working properly.
If the 2 - 3 bump shifts wouldn´t go away.....i might replace the solenoid unit, because the old fluid was more than dirty.

I´ve got ATF+4 in all of my vehicles (all A604), i was just wondering how fine the Dexron III filled Minivan worked.
 

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Might have something to do with the driving cycle of the vehicle. From what I understand, the D/MIII was nastiest to the transmission's torque converter lockup clutch, since the controller essentially pulses the clutch on and off for partial engagement under some conditions. When the clutch is fully open or closed, the wear is much less. The wear on the clutch packs would also be accelerated, but from what I understand, the TCC got it worse than any other component. However, if the vehicle isn't shifting, there's little to no wear occuring. If the van was driven mostly highway at sustained speeds, the transmission wouldn't have had to shift very much compared to a vehicle accumulating the same miles in stop and go service. The clutch in a stick shift car really doesn't wear when it's engaged (or it shouldn't); this is a similar concept.
ATF+4 is of much less benefit in the A413. The TCC in this unit is on or off; it doesn't pulse. By the early 80's, when the A413 was developed, most major manufacturers had a lockup torque converter of similar operation. Because the A413 is so similar to other traditional automatics, it can tolerate fluids designed for them. ATF+4 is still optimal, but you can use nearly anything in a pinch. The A604 was so radically different when it was introduced that it required a radically different fluid to tolerate things like pulse width modulation to smooth engagement of the TCC, which would have been difficult, if not impossible and impractical, to implement in a traditional hydromechanical automatic. It certainly doesn't deserve the bad rap it's gotten: after all, the 41TE family became Chrysler's go-to transmisson for the next 10 or so years for most of the higher-powered (i.e. V6) FWD vehicles it built, and I would say it's more than proven itself.
 

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Discussion Starter · #23 ·
Well that maybe happened to my Saratoga. It has got a red fluid in it when i bought it 4 years ago. But i have no idea which fluid it was. TCC is shot, also a quiet noise from the pump, Code 38 saved, pump is not producing the correct pressure.

But that´s another thing...

I know that ATF+4 is needed for the A604, or lets say it was made for exactly this transmission. I also refilled some A 670´s with Dexron III, works fine, maybe the better choice if it does not have a TCC.
But i have bad luck with all of my A604´s. I hope i get the Minivans trans in a good working condition without an overhaul. All of the vehicles were mostly driven in city traffic, but that is what you get from a Vienna car.

I already rebuit one A604, right now stored in the garage, hope everything works on the first (or 2nd...) try.

I´d curious if a clogged solenoid unit is causing bad shift quality without saving any code....
 

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The A670 is an uprated A413. It has a TCC, but it works exactly like the A413 otherwise. I would still recommend ATF+4, but I imagine that with the 3-speeds, this spec is more to keep the business in-house rather than speccing another manufacturer's ATF.
OklahomaWolf dismantled his solenoid pack a while back and rebuilt it, and made an excellent (as always) article on it for the main site. You may want to look here if you think that's the issue. The A604 cannot be read using the key dance, it requires a (hideously expensive) DRB to pull its codes.
The general public doesn't tend to be as conscientions as us about maintenance. The transmissions may have run for a long time with worn fluid (in addition to clutch particles, the heat of use breaks down some of the molecules in the fluid. Some fluids are also hygroscopic, meaning they absorb water extremely readily, which can cause accelerated wear and corrosion), or have been abused in other ways. You really never know how the previous owner treated the car. In the past, at least here in the States, Chrysler advertised the Torqueflite as nearly maintenance-free, with some fluid change intervals being blank, meaning they didn't expect the fluid to need to be replaced during the life of the vehicle. While this probably isn't a terribly good idea in a hydromechanical unit, the A604 is a VERY different box. Unfortunately, people tend to assume a trans is a trans and none of them need service, EVER. Not really something that you can get away with in an A604...
 

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There are aftermarket scanners that can pull TCM codes. Years ago I bought a SnapOn MT2500 just for that purpose. It wasn't cheap but is much cheaper than a DRB. The MT2500 can access the engine, transmission, ABS, transmission and body computers for data and codes providing you have the right cables and cartridges.

I loved buying cheap $500 cars where the owner was told the A604 needed rebuilt. I'd nurse these cars back to health and drive them for years without rebuilding the transmissions. Amazingly, I never had to fool with a solenoid pack on any of them. I suspect a lot of solenoid packs were replaced needlessly just like a lot of these transmissions were rebuilt needlessly. If there is a solenoid problem, there is generally an error pointing to it or a low pressure code set.
 

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Discussion Starter · #27 ·
I know, this is (definatly) the best site to get help with the A604 trans. I also rebuilt once like i said, but only flushed the solenoid pack cause the fluid was OK and clean, the torque converter broke inside.
I know the pic with the little filter caps inside the pack, but as valiant67 said, no pressure trouble - no codes. I´ll run the new TCM for i while, lets see how it works, if there´s no change, i might pull it apart...

And yes, i heard of the Snap On scanner, would a good thing to have....
 
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