fontana dan wrote: ↑

Wed Jul 05, 2023 9:35 pm

dborel wrote: ↑

Tue Jul 04, 2023 9:54 am

Did the shifting problem progress slowly over time?

I bought the car in this condition. It was shifting pretty bad the first time I test drove the car. However it improved after I drove it for a few days, changed the fluid and filter. Has been about the same ever since.

Okay, thanks for the info. I did notice another symptom yesterday while I was driving this car onto the ramps to connect to the pressure tap for the line pressure test. I noticed that the transmission was slipping or not engaging into gear while I was trying to pull the car onto the ramps. I would give the car some gas while the front tires were butted up against the ramps and instead of slowly starting move as I increased the throttle it would not move at all and then all of a sudden at certain rpm would jump forward like you dumped the clutch on a manual. This was even after driving the car to warm it up for the line pressure test. The same thing happened whether I was in "1", "2", or "D".

That sort of behavior is very typical for low line pressure. The solenoids don't actually move the valve shuttles, they're just pilots. They open an orifice, then fluid pressure pushes the shuttle to the desired position. If the pressure is too low to completely overcome the shuttle return spring, you get slow or balky shifting.

Was that happening during the stall test? Was the gas to the floor when you did the test?

VStar650CL wrote: ↑

Thu Jul 06, 2023 6:41 am

That sort of behavior is very typical for low line pressure. The solenoids don't actually move the valve shuttles, they're just pilots. They open an orifice, then fluid pressure pushes the shuttle to the desired position. If the pressure is too low to completely overcome the shuttle return spring, you get slow or balky shifting.

Okay, thanks for the insight. I guess this symptom doesn't really narrow down my search in a proper diagnosis at this point since low line pressure can cause this issue, which we still don't know for sure the cause. I will try to perform the Line Pressure Test in Reverse this weekend.

fontana dan wrote: ↑

Thu Jul 06, 2023 2:48 pm

Was that happening during the stall test? Was the gas to the floor when you did the test?

I'm certain it was happening during the stall test I just couldn't feel it, either because it was more subtle, or I wasn't really paying attention to it. I was able to feel it for sure when I was pulling it onto the ramps to perform the stall test though. I did have the accelerator to the floor when I recorded each data point during the stall test.