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The 3sp AT has been rebuilt completely in 2011 incl new torque convertor
The UPshifting is working perfectly and quick.
By means of test, I raised the vacuum from 16 inHG to 19inHG and then the bang doesn't occur anymore.
Does setting the modulator also influence down shifts ?
The 3sp AT has been rebuilt completely in 2011 incl new torque convertor
The UPshifting is working perfectly and quick.
By means of test, I raised the vacuum from 16 inHG to 19inHG and then the bang doesn't occur anymore.
Does setting the modulator also influence down shifts ?
Just finished rebuilding, installing, and adjusting a 3 speed automatic, in an early 4.5 liter car. 3 speed automatic, rebuilt and ready to install.
And wanted to mention how magnificent these transmissions function, when internally proper and adjusted correctly, in these early cars.
They upshift and downshift through the gears virtually without a flaw....completely dependent upon what you ask the car to do.
Almost like they are connected to your thoughts and desires...
Yes, I also enjoy the 5 speed cars (I enjoy just about every 928 model)....but I'm not convinced that converting an automatic to a 5 speed is the best ever "upgrade" to do.
Frankly, I'm a bit surprised that I can't ever remember someone going the other way....5 speed to an automatic.
Hey experts! I’m reviving a 79 euro with an original 3 speed. The car sat for a while. Just finished rebuilding the engine. I did a fluid flush and filter change on the transmission and did the differential oil too but it seems like there’s some slippage when I set off from stopped in Drive. It almost feels like clutch slippage would in a manual transmission. It goes away once I get going and shifts fine.
Any ideas? Hoping that it’s not a sign of a worse problem. I have not made any adjustments as of yet.
first what fluid did you use?
did you replace the vacuum modulator?
do you have a pressure checking tools Roger sells a kit
I used Dexron vi fluid. Did not replace that modulator but I did replace the vacuum hose connection to my intake spider. I don’t have pressure tools for transmissions yet. Just the standard Kjet tools.
Define slippage. Engine Rev's and car just sits still? Engine revs up to about 2K before car accelerates quickly? Does car creep forward with engine at idle and foot off the brake? I drove a 79 with a 3sp auto for 15 years. They have a very loose torque converter.
Define slippage. Engine Rev's and car just sits still? Engine revs up to about 2K before car accelerates quickly? Does car creep forward with engine at idle and foot off the brake? I drove a 79 with a 3sp auto for 15 years. They have a very loose torque converter.
It doesn’t just sit still. It’s more like the second scenario you described, with a slight vibration feel. Until it gets up to around 10 MPH and accelerates quicker. If I mash the gas pedal it sometimes doesn’t do it as much. Maybe something about specifically slower acceleration?
Fletcherra, with all due respect, I think you have made an error in the ATF. You said you used Dexron VI. I understand that Dexron VI is 'supposed' to be backwards compatible. However, it really is not. Especially for much older transmissions. Your Mercedes based Porsche A22.0* automatic requires Dexron II or III ATF. Dexron VI is just too thin. The viscosity is much lower than Dexron III.
I strongly suggest you change the fluid again, possibly 2 or 3 more times. Each time, fill the transmission with Dexron III ATF. This will purge out the Dexron VI and any old Dexron III.
Good Luck!
Also, let me know if you want/need the manuals for this transmission.
Fletcherra, with all due respect, I think you have made an error in the ATF. You said you used Dexron VI. I understand that Dexron VI is 'supposed' to be backwards compatible. However, it really is not. Especially for much older transmissions. Your Mercedes based Porsche A22.0* automatic requires Dexron II or III ATF. Dexron VI is just too thin. The viscosity is much lower than Dexron III.
I strongly suggest you change the fluid again, possibly 2 or 3 more times. Each time, fill the transmission with Dexron III ATF. This will purge out the Dexron VI and any old Dexron III.
Good Luck!
Also, let me know if you want/need the manuals for this transmission.
No offense taken here! I’m here to learn. It was my understanding that VI could work, but if it can cause that much of an issue then I can look into flushing and refilling with proper Dexron 3.
after you swap out the fluid , its been recommended to use the PEP boys Dex 3/4
NOTE drain the torque converter as well as the pan ,
you can leave the filter alone if you have replaced the filter.
Then you need to measure the fluid pressure,
buy the kit, its easy to connect, then run the car let the trans warm up .
you should be around 40 PSI but may have to turn it up to 55, but first do the suggested work before you change pressures.
You probably should be replacing the vacuum modulator get the MB part not the china copy.
Roger has the pressure kit and the modulator last I checked,
note the color of your modulator before you order.
after you swap out the fluid , its been recommended to use the PEP boys Dex 3/4
NOTE drain the torque converter as well as the pan ,
you can leave the filter alone if you have replaced the filter.
Then you need to measure the fluid pressure,
buy the kit, its easy to connect, then run the car let the trans warm up .
you should be around 40 PSI but may have to turn it up to 55, but first do the suggested work before you change pressures.
You probably should be replacing the vacuum modulator get the MB part not the china copy.
Roger has the pressure kit and the modulator last I checked,
note the color of your modulator before you order.
Is there a link to the pressure kit. I just checked and couldn't find it. Thanks
05-26-2023, 10:13 PM
