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I will intermittently (once out of 20 times) get a gear when shifting from park. Excitedly, I close the door and try and take off but before I leave the driveway the RPMs are max and the car coasts to a stop (in gear). It definitely feels/seems like a loss in hydraulic pressure. If this is the case, a new transmission is likely my only safe bet of mobility again, correct? Or should I get rid of the car and start over? I haven't even tried to price transmissions yet.
I will try that next. Do you know just how much flow is minimum? When I bought the car and did a flush of the tranny with the same hose it would fill a gallon jug fairly quick. Also, the tranny is filled to just below the "HOT" line when cold (but not over). That wouldn't cause any of this would it? Thanks in advance.
It could be that the tranny fluid pump is failing, but not enough to throw a TCM code? When I did a Gibbons tranny flush with this same Geartronic, I seem to recall the flow rate being 2 quarts / 30 sec. However, the pump is not pumping against any back-pressure during the Gibbons, whereas it encounters the full load of propelling the car as backpressure when driving -- if there were an internal leak in the pump that caused loss of fluid pressure, that would be enough to stall out the torque transfer. Does the TCM monitor fluid pressure?? I don't know. Xfingers described a way to measure the pressure with an external gauge.
No pressure sensor internal to this tranny that I'm aware of. If there was, TCM can probably do better adaptation and we'd be able to do much better diagnostics.Quote:
Originally Posted by pbierre
I guess TCM adaptation probably just compare engine output speed against transmission output speed to determine shift smoothness.
In that case, I would put in a NEW switch...Quote:
Originally Posted by zenwalrus
Your disassembly and cleaning immediately preceded this...so, it sounds to me like something wasn't right when you put it back together...
Not cheap, but much cheaper than a new transmission.
https://www.ipdusa.com/products/1012...-volvo-8636441
Have you checked the axles? Broken, stripped splines at the wheel bearings, not in the transmission all the way.
Better yet when you put the car into park are you able to make it move/roll by pushing it?
Astro makes a good point. If you cleaned the switch before any of this happened, did something prompt you to take it apart?
The transmission has been worked on. You mention the trans has been rebuilt and you also replaced the 3 solenoids. This tells me you opened up the valvebody/removed the valvebody cover. When removing/installing a VB, there's a metal rod or dowel which fits into a lever with a little hole in it attached to the gear switch. If somehow this rod has slipped out of the hole, you're not gonna be able to change gears! You can move the shifter all you want but nothing will happen in the VB. Have no idea if this is your situation.
Have you seen Astro's tutorial in the How-to area section of the resources tab at the very top of the screen, "Valve Body Replacement". For some reason, the link won't open when I click on it but it's got good pictures of how the metal rod from the VB engages with the gear switch. In general, if you took off the valvebody cover but didn't loosen any bolts that attach the VB to the housing, it seems like it would be difficult for that metal rod to become disconnected.
If you replace the transmission ($$$) and the problem is elsewhere ($), the car might still not move.
Here's a pic from Astro's tutorial; click to expand. I circled in red the lever with the hole:
Attachment 8970
Some more back story...Last year, I got a code while driving and put in limp mode (failure to engage I think it was?) was able to clear it and restored full abilities to the transmission. In reading further it was suggested that sometimes switches can cause this and cleaning them could not hurt. I work in an electronic shop so I had what was necessary to tear apart and it looked brand new, no oxidation or worn contacts. Ran fine with no issues for about 8 months and then the coasting to a stop while in gear started intermittently happening, and I bought the solenoids. Which brings me to here. NOTE: The dash display promptly shows all gears at the same speed that I change them, indicating no issues electronically that I can tell.
Cannot move in Park...
I changed all solenoids with the valve body in place from underneath the car (and have the sore neck to prove it lol). I decided not to pull the valve body out to keep it simpler. Also, I get an audible sound of the car going into gear about one out of every 20 or so shifts into Drive, and the car will go for about 10 feet, the RPMs go high and the car coasts to a stop like it lost hydraulic pressure. Just the weirdest damned thing, and of ALL the Volvos I've owned (at least ten) this is the only transmission issue I've ever encountered. I don't know whether to invest in a new transmission with the car on 200K miles. Thoughts? I appreciate it.