Automatic transmission Governor microprocessor new!

[alexdmc1]

I installed a modern microprocessor-controlled unit, which has changed the driving experience: 1) shifts are too fast, accompanied by a slight jolt, especially when the car is hot (uncomfortable); 2) indecisiveness when shifting from third to second gear when driving slowly. Does anyone else have the same driving experience? Could it be a problem with the new TIP102 chip-controlled unit or a problem with my automatic transmission? Thanks, and best regards, everyone!

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[glowof1000suns]

I had mine rebuilt a couple of years ago, and aside from it fixing the wackiness I had with my failing unit, I didn't experience any noticeable change compared with before it started to go south. Mine was done by DMCH. Where did you get yours?

[alexdmc1]

The unit was purchased through a European dealer. After the oil gets hot, the gearbox performance worsens.IMG_20230810_140523~2.jpg

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[glowof1000suns]

If you're getting different results under hot conditions, it kinda sounds like your fluid may be low. Successfully checking the fluid level on our cars leaves a lot to be desired, but in case you've never done it before, make sure the car is fully warmed (fans cycle at least once). When adding more fluid, move the shifter across all gears and be sure to give it a minute or two between readings.

[alexdmc1]

Thanks for the reply. I'll check it tomorrow, I recently replaced it. I'll do as you say. The gearbox never slips under any circumstances, it was expertly serviced, new oil pump. I performed the test at 2,500 rpm as per the manual = 8 bar, perfect! I discovered that: the pressure taken with the pressure gauge varies greatly between hot and cold: in P/R/N/D when hot at idle 2/3 bar, when cold 6 bar.

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[David T]

Make sure the vacuum modulator is connected to the vacuum line and it is not leaking vacuum. Besides setting the line pressure it is supposed to lower it when it gets high vacuum to soften the shifts. What fluid is in your transmission? If it is not the old Dexron, that could be the problem. If your motor is running too hot the transmission will also run hot. Downshifts will always be "problematic", they are controlled by the internal valve body, not the governor, aka shift computer. BTW, a slight "jolt" is still OK, when there is no "jolt" you are actually in 2 gears at the same time to soften the shift but you wear the clutch packs out faster. I install stiffer springs in the clutch packs to give firmer shifts. It is the Delorean version of a shift kit for the Renault automatic transmission. Do check the fluid level as per the Service Manual. It should not be low but it also should not be overfilled when hot. Not only is the level important, the color and smell is also important. You should also check the level in the final drive, it is a separate level but you have to get under the car to check it. I also suggest you check the adjustment on the cable to the shift computer and the gearshift linkage.

[alexdmc1]

It?s good to hear from you! Thanks for the reply. The vacuum modulator isn't leaking; it has been tested. The pressure gauge reading confirms that the pressure is lower with light throttle input, whereas it is much higher at full throttle. I?ll check the level again. I?ve tried various fluids?100% mineral ATF Dexron 2 and synthetic ATF Dexron 3?but there was no difference. The fact is that at idle, in all positions, I have:

Cold: 5/6 bar in P/N/R/D
Hot: 2 bar in P/N/R/D

When shifting from second to third gear, if you don't press the trusty accelerator at all, the result is a massive jolt!

I installed a new genuine control valve and sleeve assembly; there is little difference.

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[Michael]

I have read time and time again the new rebuilt units with the newer boards are flaky. That said, be sure your detent cable is properly adjusted. If it's out just a little, it will play games with you.