I had another automotive enthusiast ask if there was a difference in the Throttle Valve (TV) pressure levels between Park and Neutral. I had always set my TV pressure with the AOD in Park. But, our colleague advised the manual specified it should be in Neutral. Okay, fair enough. It is a valid question despite what the manual may say, but with what the manual says it is even more important to find out if there is a difference or not. And if there is a difference, how significant is it?
Also, it is worth mentioning that I have done the TV pressure testing and adjustments when the engine and transmission are in normal operating temperature, and with the AOD fluid level being at its proper level. I had not mentioned that in my prior video, and as pointed out to me by "Bentley Nut" in a pleasant comment, I should have done so.
What I did not show in this video is what it took to get the Oil Pressure gauge connected to the center test pressure port on the AOD. I have a link below that shows a prior demonstration re: how to check and adjust TV pressure on an AOD transmission after installing the oil pressure gauge in the proper test port. Please feel free to watch the other video (link below) for more information. This video you are looking at currently (9/7/2022) is really more about showing how much difference there is in Neutral and Park in the TV pressure when using the 0.275" thick spacer tool. More info re: the 0.275" spacer tool, and how to adjust the TV pressure, is found in the videos in the link below:
• AOD Line Pressure Port...
In short, the TV pressure in Park in this video is 39.5 PSI. In Neutral that drops to 38.0 PSI. So, I saw about 1 1/2 PSI difference between Park and Neutral positions. That is not a lot of difference, but it is enough of a difference for me to say that, yes, doing the TV setting and measurement would be more correctly done in Neutral as opposed to doing it in Park.
In my case I intentionally went higher than the 30-35 PSI specification from Ford, as I wanted to increase the speed at which the 1-2 and 2-3 upshifts occurred, along with a firmer upshift. I had set it to 39.5 PSI, and figured it was close enough to 40 PSI to call it done. The upshift speeds indeed increased a little bit, and the upshift are firmer, just as I had anticipated.
The nominally higher TV PSI is not going to hurt the transmission What hurts these AODs is when the TV pressure is not high enough, which can occur for any number of reasons - one of which is when some older plastic or nylon bushings fail, and the cable length to the TV linkage is effectively lengthened, which causes the TV pressure to drop enough at time to cook the internal friction plates.
25 авг 2024