Building an a604 to handle 1000hp? How to protect the input shaft.

[Reaper1]

I've actually thought about the exoskeleton thing quite a bit. It *might* work. We know that girdles and the like work, so I think there might be merit to the idea. I've also thought about welding stiffening "straps" to the outside of the case as well. As has been noted, welding to these cases is not a lot of fun.

I think we might be getting ahead of ourselves, though. So far we don't need to worry about the case because we are still trying to figure out how to get the internals to withstand the abuse and how to control the electronics. The bracing idea is a good discussion for 5-speed's though as they seem to need that sort of thing more than the autos...again because of shock load more than anything else IMHO.

[Vigo]

Vigo was saying at some point he thought most case flex in moderately built motors was caused by torque multiplication at the starting line when drag racing.

My thinking was that while you are brake boosting up to stall the converter is giving some torque multiplication and during that time, that's actually the highest input torque the trans will see during the whole run. And unless you have a trans brake, that load is all going through the diff out to the brakes. I think i originally brought that up because OhioRob broke his trans right on the line during brakeboost or RIGHT after letting off the brakes.

Somebody correct me if they're sure i'm wrong.

[Reaper1]

OK, yes. Now I see what you're saying. It makes sense. For some reason I seem to forget that the TC does have that multiplication factor in that first little bit of a run. So, it is sort of like dumping a clutch. If it were a trans brake, then it would be almost exactly like dumping a clutch.

[Force Fed Mopar]

Any more updates on this? Looks I will be building one for the black Daytona soon...

[Force Fed Mopar]

Bump, I just had the A604 for the black Daytona rebuilt with all the standard upgrades, hardened planetaries, input shaft and hubs, late model solenoid pack, high friction clutches, new converter etc. Hopefully can get it in before the end of summer.

[Reaper1]

Woot!!!

[turbogtu]

Could the processor have a masked ROM and not having the seed codes to bootstrap won't work to extract onboard eprom, only program it. Would need to decap processor to read the rom. It's what arcade guys do. I tried decaping one of the '95 copyright model processors from a 97 caravan. Got ill results. Looks like a 68hc16z2.

Also as far as bullet proofing apparently there's a 4 gear front planet. Must be from a 62te or late 42rle.

[Reaper1]

Mine had 4-planet front gears. It was rebuilt in 1998.

[turbogtu]

Mine had 4-planet front gears. It was rebuilt in 1998.

Wow 98. Would you happen to have a Chrysler part number?

I see the line pressure drops in direct and overdrive. Why would Chrysler do this? Drum cant handle it or shift feel? I see blocking off the Z hole in the channel plate keeps it the same as 1st and 2nd. I was thinking shimming the regulator spring but that would raise the pressure too much in reverse , 1st , 2nd.

[135sohc]

4 pinion did not come out until mid 00's. The 3 pinion part number planetary supersedes to the 4 pinion but theres still tons of old stock 3 pinion assemblies out there and the usual aftermarket suppliers sell both anyways.

[ShelGame]

Could the processor have a masked ROM and not having the seed codes to bootstrap won't work to extract onboard eprom, only program it. Would need to decap processor to read the rom. It's what arcade guys do. I tried decaping one of the '95 copyright model processors from a 97 caravan. Got ill results. Looks like a 68hc16z2.

Also as far as bullet proofing apparently there's a 4 gear front planet. Must be from a 62te or late 42rle.

Yes, it could.

It also could be that the chip my file came from was actually a 64k chip, and only half of it was read. I need to pull a chip myself and have a look. I also need to figure out (again) how to bootstrap one. I did it years ago, but never got a good read from it.

[Vigo]

I see the line pressure drops in direct and overdrive. Why would Chrysler do this?

Reduce pumping losses for fuel economy, most likely. Probably also a shift 'harshness' component. Nice to know it is simple to defeat! Wouldn't make 4th gear strong enough to be useful, but it may help 3rd gear for higher power builds.

[Lpgc]

New member... Sorry to resurrect an old thread.

I have owned several Chrysler Grand Voyagers, all with the 3.3 petrol, mostly mid 90s to early 2000's models and have had problems with the A604 in all of them even at stock power. When they break I usually just pull the box from a scrap Grand Voyager and put it in, but I always change the filter, fluid and add a cooler. I don't use overdrive if working the box hard (such as when towing a trailer), even with a second cooler the box seems to get hot if TC isn't locked and I know about the week OD.

Recently had problems with the A604 in my current 2001 3.3 Chrysler Grand Voyager but changing the valve body seems to have cured it at least for now. But this set me thinking... next time it breaks, and I know there will be a next time, instead of putting in a trans from a scrapyard I'd rather build a trans myself, hopefully with beefed up components that I know will last.

I would like a bit more engine power too, especially for when towing, so am considering putting a turbo on the 3.3. I convert vehicles to run on LPG (propane) for a living and mapping the engine to run with a bit of boost won't be a problem, but since A604's break at stock power I bet they'd break really quick with just a bit of boost... so if I fit a turbo I'd better upgrade the trans first?

My first real question is - what parts should I use in an A604 to handle maybe 300bhp reliably and hopefully without much expense?

I'm in the UK, it's not so easy to get hold of trans parts here, there are no trans shops and there isn't the knowledge base even at dealers etc. Over here if your trans breaks outside the warranty period you're pretty much left with 3 options - buy second hand box from a scrapyard, buy new box from a dealer, get it reconditioned/rebuilt by a specialist.. except the specialists here are likely to only want (or know how) to fit stock parts and I wouldn't trust many to do a full rebuild.. a lot of them would just replace the broken component, and I don't want stock parts. I see 'heavy duty' A604 bits on Ebay such as welded hubs, different frictions and steels... but what should I be looking for?

Another question - over here there are 2.8 turbo diesel Grand Voyagers fitted with A604s, would guess the 2.8td makes a lot more torque than the 3.3 petrol, so I wonder if an A604 from a td model would be stronger anyway?

Thanks for reading, hope you can help.

Simon

[c2xejk]

Let me ask the just in case question, what transmission fluid are you using? ATF +4? Anything other than ATF+4 (ie. Dexron) can kill the transmission pretty quickly...

[Aries_Turbo]

most of the issues with the 604 is from slow shifting which burns out the clutches when increased power/torque is applied.

a turbo neon dude (racerstev) put down 650-700hp through a pretty much stock rebuild 604 with an aftermarket controller that allowed you to make the shifts so hard they just about hurt. TCS was the company that made the controller but i dont think they make it anymore. and it was like 700$

it also didnt have the adaptive programming that the factory controller has that accounts for clutch wear.

the 604 is pretty tough... other than overdrive. it just needs a controller that keeps the adaptive programming and allows for shift firmness adjustments (ie a hacked factory controller) as the power rises.

Brian

[Lpgc]

I normally use this fluid http://www.carlube.co.uk/transmissio...smission-fluid - fully synthetic and supposedly atf+3 / atf+4 compatible. Between finger and thumb this stuff feels thinner than any fluid I've taken out of an A604 but I dunno if everything I've ever taken out of an A604 has seemed thicker just because it was old fluid full of worn clutch material etc? The proper Mopar stuff is only available from Chrysler dealers here, special order and very expensive, would probably cost over £100 to do a full fluid swap but I don't mind paying that if it will be better than the stuff I've been using. I've read about even dealers being confused on which spec fluid to use in these transmissions though, so I dunno if even the dealer would supply correct stuff. I had a worn CV joint on my car so I swapped the driveshaft out of a scrap vehicle, cured the ticking CV but now ATF leaks past the trans driveshaft seal. I purposefully haven't addressed the leak yet, thinking continued leak and topping up with fresh fluid will make for complete fluid change... run the car for a few months like this now, topping up with maybe a few litres per week, seems to have done as intended because the fluid in my trans definitely became very clean! Even cleaner now since changing the valve body just the other day.

Wouldn't really want to go the aftermarket controller route for a few reasons... expense, complexity and potential for damaging trans during setting up. Also, my understanding is that the standard controller tells the engine ECU (via serial link/canbus) to retard ignition timing during shifts, to reduce engine torque during shifts anyway... If that's the case, and if aftermarket controller can't tell the engine ECU to retard timing, would seem benefit from faster clutch engagements etc would be at least partially be offset by the engine not reducing torque during shifts? I'm not a racer, so don't need fast shifts that might make for 0.1second quicker on a drag strip etc, just want the trans to hold together.

I've noticed a difference in shift behaviour between my post 2000 Chrysler Grand Voyager and pre 2000 Chrysler Grand Voaygers... the earlier models seemed less reluctant to change down than the later model, wonder if anyone can tell me if that's how it's supposed to be or if it points to a problem? Sometimes later model doesn't seem willing to kick down from 4th to 3rd but keep pressing the throttle further and it will kick down to 2nd.. This situation is now exactly the same as when I first bought the late model (now after the recent change of valve body). Before changing the valve body it would sometimes only use 2nd 3rd and 4th gear (not use 1st even from standing start, and sometimes not kick down to 1st), also when that happened the TC wouldn't lock up. After changing the valve body it sets off in 1st, kicks down to first, TC locks up and it all seems pretty normal and fixed, except as said above the shift behaviour is still a bit different to pre 2000 models I've owned.

Above I mentioned possibly turbocharging the 3.3, I'll start another thread on that (don't want to go off topic here), but as anyone done this? I wonder how strong the 3.3 bottom end is? I probably wouldn't even reduce compression, because I'll only run boost when the car is running on LPG which has a far higher octane rating than petrol and it isn't my intention to run a lot of boost.

Simon

[Ondonti]

Want that diesel transmission.

There is a section for 3.0 that has a recent 3.3 engine strength topic. Keep the Trans questions here, engine there. Engine won't be your problem.

I normally use this fluid http://www.carlube.co.uk/transmissio...smission-fluid - fully synthetic and supposedly atf+3 / atf+4 compatible. Between finger and thumb this stuff feels thinner than any fluid I've taken out of an A604 but I dunno if everything I've ever taken out of an A604 has seemed thicker just because it was old fluid full of worn clutch material etc? The proper Mopar stuff is only available from Chrysler dealers here, special order and very expensive, would probably cost over £100 to do a full fluid swap but I don't mind paying that if it will be better than the stuff I've been using. I've read about even dealers being confused on which spec fluid to use in these transmissions though, so I dunno if even the dealer would supply correct stuff. I had a worn CV joint on my car so I swapped the driveshaft out of a scrap vehicle, cured the ticking CV but now ATF leaks past the trans driveshaft seal. I purposefully haven't addressed the leak yet, thinking continued leak and topping up with fresh fluid will make for complete fluid change... run the car for a few months like this now, topping up with maybe a few litres per week, seems to have done as intended because the fluid in my trans definitely became very clean! Even cleaner now since changing the valve body just the other day.

Wouldn't really want to go the aftermarket controller route for a few reasons... expense, complexity and potential for damaging trans during setting up. Also, my understanding is that the standard controller tells the engine ECU (via serial link/canbus) to retard ignition timing during shifts, to reduce engine torque during shifts anyway... If that's the case, and if aftermarket controller can't tell the engine ECU to retard timing, would seem benefit from faster clutch engagements etc would be at least partially be offset by the engine not reducing torque during shifts? I'm not a racer, so don't need fast shifts that might make for 0.1second quicker on a drag strip etc, just want the trans to hold together.

I've noticed a difference in shift behaviour between my post 2000 Chrysler Grand Voyager and pre 2000 Chrysler Grand Voaygers... the earlier models seemed less reluctant to change down than the later model, wonder if anyone can tell me if that's how it's supposed to be or if it points to a problem? Sometimes later model doesn't seem willing to kick down from 4th to 3rd but keep pressing the throttle further and it will kick down to 2nd.. This situation is now exactly the same as when I first bought the late model (now after the recent change of valve body). Before changing the valve body it would sometimes only use 2nd 3rd and 4th gear (not use 1st even from standing start, and sometimes not kick down to 1st), also when that happened the TC wouldn't lock up. After changing the valve body it sets off in 1st, kicks down to first, TC locks up and it all seems pretty normal and fixed, except as said above the shift behaviour is still a bit different to pre 2000 models I've owned.

Above I mentioned possibly turbocharging the 3.3, I'll start another thread on that (don't want to go off topic here), but as anyone done this? I wonder how strong the 3.3 bottom end is? I probably wouldn't even reduce compression, because I'll only run boost when the car is running on LPG which has a far higher octane rating than petrol and it isn't my intention to run a lot of boost.

Simon

[135sohc]

Those universal pour it in anything transmission fluids are a disaster. Amazon UK shows better pricing, still a ripoff but its atleast the right fluid. Here is the states walmart sells an approved ATF4 for less than $5 a quart, no one else even comes close.

[Lpgc]

I see all your points regards ATF.. But how would proper spec ATF that has been in the trans for 50000 miles compare to new ATF that is supposedly +4 spec but has a different mix of additives etc.. Thinking the properties (including friction properties etc) of ATF change over time, additives wear out, so how sensitive can the trans really be to ATF? Most of the times I've had trans failures I wasn't even working the box hard and just prior to the failure the box seemed fine. Would think if ATF was the problem, shifting wouldn't be so good before failure?

I've owned several Grand Voyagers... The first one had trans stuck in limp home mode when I bought it, fixed easily by changing the solenoid pack until the trans let go around a year later. The 2nd was bought as a trans donator to fix the 1st. The diff in that trans let go so I made one good transaxle out of 2 and put it back in the 1st car, ran that for a year until again the trans broke. Bought 3rd as a good running car, again trans lasted a year, couldn't be bothered to change the trans so just bought a 4th (current) car, few months after owning it the trans started with the odd shift behaviour (described above), changed the solenoid pack but made no difference, drove it for months with the odd shift behaviour until I recently bought a 5th car... Swapped the input/output speed sensors and valve body from the 5th to the 4th and 4th seemed good for a few days, reverted to odd shift behaviour for a few days but now seems OK again.. though I'm sure it will revert to odd behaviour again soon! I removed 5th's TCU, ECU with key etc, so I can try them on 4th car when I get time. Out of all the above trans, the only trans I ever found metal bits in was the one with the broken diff.

When current (4th car) is running well I get only one OBD code from the engine ECU 'internal memory checksum incorrect', which points to a bad engine ECU? This code is constant but doesn't seem to effect the trans shifting OK, when the trans doesn't shift OK I get TCU OBD code P1175 'solenoid switch valve latched in TCC position' (is this the correct definition of P1175?). Any ideas on what could be causing this code?

Simon