re4r03a vs. re4r01a valve body

[texasoil]

what would be 'the solution' is a resistor switching network that goes to the higher resistance (50 ohms) for just the 2-3 upshift, and leaves everything else at OEM setting. Hint-hint to some of the real electronics experts here

[elwesso]

You could tap that from the shift solenoid B signal, to have it switch to a open circuit only for the 2-3 shift...

It probably wouldnt be too hard to fix, but then again I cant get my cruise control working

[3Q Jay]

what would be 'the solution' is a resistor switching network that goes to the higher resistance (50 ohms) for just the 2-3 upshift, and leaves everything else at OEM setting. Hint-hint to some of the real electronics experts here

Hi Keith! I was thinking something along those lines: relay actuated to have the resistor in for all but the 2-3--just haven't researched enough to see if there is a 2-3 TCM output signal to use as the trigger.Wes may have hit the mark with the b solenoid, have to digest....

Today, with the 82 ohm resitor, it was as perfect (over all 1-2,2-3,and 3-4)as I've felt so far. But, the small resistors are getting too hot...so i took Robert's cue and stopped by Fry's after work. annoying place. everytime i ask them for something they don't have--their response is like pfff-why would you want that? we don't carry it. [implied--therefore it must not be worthwhile to even consider]. but i digress.i did mange to find a pack of 10 watt 68 ohm. plugged it in and it's passable. just a hint of delay on hot 2-3. i think i can live with this until mouser or some place comes thru with the optimal resistance.

regarding tech's back emf, the transmission solenoid will *certainly* dump energy back into the system when it de-energises. But, my logic is that if the factory put a resistor (only) there (schematic representation suggests this), then a resistor only would be satisfactory in place of, without demanding either a cap from highside to ground, or a blocking diode.i guess it would be good if we could confirm just what's really on the factory plug-in module.it's been about 20 years since i designed a circuit, i'd welcome other eyes.

[elwesso]

Wow this could be simpler than I thought.....

Heres a chart of the shift solenoid positions.....

in 1st gear, shift solenoid A and B are both "on"in 2nd gear, shift solenoid A is "off" and B is "on"in 3rd gear, both shift solenoids are offin 4th gear, shift solenoid A is on and shift solenoid B is off...

So from 2-3, all the TCU does is turn off shift solenoid B.....

There are 4 solenoids in the transmission, shift solenoids A and B, overrun solenoid and the line pressure solenoid.. I would assume the overrun solenoid would cause torque converter lockup.....

in either case, this should be very simple.....

[RobertsnewQ]

Hi Keith! I was thinking something along those lines: relay actuated to have the resistor in for all but the 2-3--just haven't researched enough to see if there is a 2-3 TCM output signal to use as the trigger.Wes may have hit the mark with the b solenoid, have to digest....

I think the smallcar kit and/or a higher resistance would solve the prob. without having to add a relay to the B solenoid circuit, and would have the benefit of applying only under high throttle...

It's just frustrating that we have to do it this way - I wish the TCU software were available somewhere, or a programmable TCU. All of these parameters would be no further than an eprom burner.

Quote »Today, with the 82 ohm resitor, it was as perfect (over all 1-2,2-3,and 3-4)as I've felt so far. But, the small resistors are getting too hot...so i took Robert's cue and stopped by Fry's after work. annoying place. everytime i ask them for something they don't have--their response is like pfff-why would you want that? we don't carry it. [implied--therefore it must not be worthwhile to even consider]. but i digress.i did mange to find a pack of 10 watt 68 ohm. plugged it in and it's passable. just a hint of delay on hot 2-3. i think i can live with this until mouser or some place comes thru with the optimal resistance.[/quote]Sounds like you found a good value - I'll head down there and get myself one on Monday. I so agree with you about Frys - the people they hire are barely competent...

Quote »regarding tech's back emf, the transmission solenoid will *certainly* dump energy back into the system when it de-energises. But, my logic is that if the factory put a resistor (only) there (schematic representation suggests this), then a resistor only would be satisfactory in place of, without demanding either a cap from highside to ground, or a blocking diode.[/quote]If that's the case (its for back EMF), the exact value won't matter too much either...

Quote »i guess it would be good if we could confirm just what's really on the factory plug-in module.it's been about 20 years since i designed a circuit, i'd welcome other eyes.[/quote]I'm worse - one undergraduate class in analog electronics is the extent of it for me.

[3Q Jay]

Robert, thanks for comparing notes.

If that's the case (its for back EMF), the exact value won't matter too much either...

just to be clear, i'm not certain that the resistor is there purely for back EMF reasons-- i don't have enough data to know what the dropping resistor is there for. I was saying that the solenoid will have energy to dissipate, but it's not clear to me what's inside the TCU. Maybe there are quench circuits already in place inside the TCU. What is apparent from the schematics [although admittedly i haven't gone to verify first hand], is that there is a direct path between pin 1 of the TCU and the solenoid control terminal. If pin 2 is ground inside the TCU (and assuming pin 1 is a constant current source [driver] when actuated in the TCU), then the resistor does 2 things: it shares the driver current with the solenoid [higher resistance=less current in the 'dropping' path= higher current at the line pressure solenoid], and 2 it is a dissipative path for the back emf energy when the driver shuts off. for the same reason that the higher resistance helps the sluggish solenoid, it will also current limit the backemf. depending on the amount of stored enrgy, this may have the undesirable effect of allowing (more) reverse current at the driver output [pin 1 on TCU]. so in a lengthy way, I'm saying that depending on how good the quenchers are in the TCU, the higher resistor may be stressing the driver.

at the moment, I'm thinking that a diode forward biased between pin 1 and the junction point of the dropping resistor would provide some extra protection for the driver (blocking diode). again, I'm rusty here so more eyes would be helpful.But I'm also not wild about the idea of permanently hacking up the wire harness.If we knew what was inside the TCU, that might put my mind more at ease.

[3Q Jay]

back to the original thread title: i just received a 'shift kit' that applies to both the -01a and -03a (the valve body mods are the same save for one hole that gets a kit supplied plug on the -01a).

i'm abandoning plans for a relay actuated unique resistor for the 2-3 shift. logic tells me that the electro-mechanical timing sequence involved for closing said relay before the 2-3 upshift signal to the B solenoid and the line pressure solenoid is not practical.

blocking diode 1n5821 on order from mouser. haven't decided what i'm gonna do with it yet.

[elwesso]

back to the original thread title: i just received a 'shift kit' that applies to both the -01a and -03a (the valve body mods are the same save for one hole that gets a kit supplied plug on the -01a).

i'm abandoning plans for a relay actuated unique resistor for the 2-3 shift. logic tells me that the electro-mechanical timing sequence involved for closing said relay before the 2-3 upshift signal to the B solenoid and the line pressure solenoid is not practical.

blocking diode 1n5821 on order from mouser. haven't decided what i'm gonna do with it yet.

So you ended up getting one of those modified valve bodies?? let us know how it works...

Did you get new solenoids too?

[3Q Jay]

So you ended up getting one of those modified valve bodies?? let us know how it works...

Did you get new solenoids too?

nope. not ready to send John $600 just yet [although he was pleasant enough on the phone].i bought a countermeasure kit from bulkpart. it consists of mods for increased planetary lube, some 'improved' seals, a BEEFY 1-2 accumulator spring [like i want the 1-2 any firmer.....], and of course the all important template for drilling out the vb separator plate.it's not marketed as a performance shift kit, but it's increasing my understanding of this gearbox. there seem to be a few folks out there [not on our board, per se] that wish to keep these things veiled in secrecy.

i say fuhgedddaaabouddit!

[RobertsnewQ]

there seem to be a few folks out there [not on our board, per se] that wish to keep these things veiled in secrecy.

i say fuhgedddaaabouddit!

Yes, I'll agree whole-heartedly about that one. I mean, we're talking about a HUGELY popular trans with dozens of applications, but it's almost impossible to find info about it. I have a good friend whose dad owns a transmission shop in Lake Elsinore, and so I asked him about it the other day. He said, "Yeah, I can fix that, but I don't need a shift kit. I just know what parts to modify." but wouldn't tell ME which parts. Nice guy, just didn't want to share.

Oh well.

[sheadee240]

I also have a slow 2-3 upshift on my 94 Q45.Wes did you ever try that IPT solenoid kit or a performance valve body? Did anyone try that smallcar vacuum controlled resistor?

Hmmm.. Not bad... good prices..

i think im gonna get some IPT shift solenoids and see if that helps it...