It sounds like the same issue as before.
Did you lubricate that pivot?
Lot of these speed related problems are generally caused by something in the tape path that's either not pulling the tape through correctly or presenting some friction.
Lubricating that pivot allows the pinch roller to apply enough pressure to the tape/capstan interface so whatever speed the capstan is moving at, the tape will too.
The other most common cause of speed irregularities is a dirty tape path. There are some tapes that exhibit what's call stick shed syndrome. It's a breakdown of the binder that holds the oxide onto the tapes backing. This leaves tiny bits of sticky stuff from one end of the tape path (particularly on the heads and the inside corners of the guides) and when there's enough of it, it can stop the machine dead in it's tracks.
One thing you need to remember is that tapes can be damaged by having too much tension applied to them while being played. For this reason, the tension needs to be just high enough overcome the normal friction created by the tape path. To make a long story short, it doesn't take much resistance to effect the tape speed.
So, take a magnifier of some sort and a good light and clean the tape path completely. If there's sticky shed, this will take up to half an hour (alcohol won't clean this stuff off). If you've cleaned it and it just took a minute or two, you haven't done what I'm talking about. These specks of sticky stuff might be as small as the point of a pin but if you have enough of these, it would explain your problem.
BTW, the tape most commonly associated with sticky shed is Ampex/Quantegy 456 but most of the production from these two companies after the mid 70's is also suspect. There are other tape formulas that have this issue too so be sure and use something like some fresh RMGI tape for your testing. Otherwise, every time you play the same tape, it will deposit more on the tape path and you'll have to clean it all over again.
