Same problem on both my 83 Dodge van (318/904) and my brother's 83 Dodge van (225/904). My 904 is the 1983 original lockup version, my brother's 904 is a 1973 unit that came out of EricW's old Satellite (he got it out of a Dart in a junkyard).

Symptoms:

Slow engagement into 1st, random flare up at 1-2 shift, flare-up at 2-3 shift, flare-up at 3-2 downshift or kickdown-2 shift.

Already adjusted the front band (the one accessible on the outside of the transmission case), going to be adjusting the rear band in a week or so (the one you have to pull the pan to do). Transmissions are full with ATF+4 and fresh filters.

What might cause these flare-up problems? How do I diagnose them? I have a shop manual and gauges to test line pressures, should I be using those?

While we are in the transmission pan, what tricks can we do (short of installing a shift kit) to firm up shift and reduce gear overlap? Remove accumulator spring? Adjust line pressure? ???

Any tips will be greatly appreciated. I hate knowing nothing about how an automatic transmission works....

I'm wondering if you started having these problems when you switched to atf+4? For sure, if you have the pressure gauges,then perform the needed tests before tearing them down.

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V8?? We don't need no stink'n V8!!

Possibly, but all my research indicates that +4 replaces all older Mopar recommended fluids and is superior to them.

The additive package in +4 is designed for compatibility with electrical solenoids and has a highly friction modified formula to prevent torque converter clutch shudder during partial lockup EMCC. Your older A904s do not have either. Although the bottle does not say "synthetic" the amount of additives in +4 puts it in the category of a synthetic fluid. There is no question that synthetic fluid is superior...I put synthetic in all of my rebuilds...However, in a trans older than 1985 and has not been rebuilt with modern seals, I would use a fluid that was closer to the original for seal compatibility...Dex III/mercon is probably the closest.

That aside...I am curious about your pressure readings.

A couple of things I am thinking at this time...
1. The high solvent content and detergents in the ATF+4 have "cleaned the inside of your transmission/torque converter and all of the resulting sediment has clogged your filter. Cut it open and see whats in there.

2. Your kickdown linkage is improperly adjusted.

3. Your valve body is loose.


The kickdown band adjustment is critical for 1-2 and 3-2 shift timing...I would not deviate much from stock settings on this one. Furthermore, it is impossible for that adjustment to cause a 1-2 and 2-3 flare...it would probably be one or the other.

Based on your symptoms, I think you are looking at something that is lowering line pressure across the board. That's why a pressure check is a critical step before further diagnosing the problem.

Thanks. I won't have my brother's van back in my clutches for another two weeks, but I will be doing the pressure tests then. I will also be double checking the band adjustment, and checking the filter, even though I replaced the filter about two months ago.