Harsh reverse engagement/TCM 0039

koolhandluke · Post by **koolhandluke** » 02 Aug 2021, 16:05

Greetings..'99 V70/323k(purchased new/ best car ever!). When shifted into reverse, I have developed an intermittent harsh engagement. Performed a drain and fill mainly to get a peek at the fluid; kinda dark, but not burned. When performing garage shifts, I was able to duplicate the harsh engagement consistently by moving the shift lever to the extremes within the reverse position detent, got a flashing "up" arrow and a CEL. Pulled the code on my Icarsoft Volvo scanner and came up with a TCM0039/gear shift selector faulty signal. Cleared that, but still had a CEL. Disconnected battery, and was able to clear that as well. There are no drivability issues whatsoever. Reverse works; normal 1 through 4 shifts and TC lockup. I suspect a PNP switch(it's original). Any and all comments welcome. Thank you in advance! Steve

Post by **RickHaleParker** » 05 Aug 2021, 17:59

Check the wiring, clean the connector and check for slack in the gear shift cable on the gear-shift position sensor ( AKA PNP ).

The gear-shift position sensor is mounted on the transmission. You will know it when you see it because it is connected to the gear shift cable.

If it none of the above check the cable adjustment.

Still none of the above. Could be a stretched shifter cable, defective gear-shift position sensor (PnP), slack in the shifter.

Gear-shift position sensor: Part number 9466012. Used in 1994 - 1997 850 1998 - 2000 S/V/C70.

TCM-0039 Possible sources.

Contact resistance in terminals.
Short-circuit to supply voltage or ground in the signal cable.
Open-circuit in signal cable.
Gear-shift position sensor incorrectly adjusted.
Defective gear-shift position sensor.

Post by **BEJinFbk** » 05 Aug 2021, 20:44

How's your front motor mount?
The one by the harmonic balancer.

koolhandluke · Post by **koolhandluke** » 06 Aug 2021, 06:37

Thank you all for the replies. Torque strut and front motor mount are recent and in good shape. The ability to duplicate this by moving the the gearshift within the extremes of the reverse detent position make the shift cable itself(stretched or out of adjustment) a great place to start my investigation. I will check its condition,,clean all connections, and perform another drain and fill. She's resting at home while I'm on vacation, and I'll post my comments once I get into the repair later this month....Steve

koolhandluke · Post by **koolhandluke** » 06 Aug 2021, 06:37

Thank you all for the replies. Torque strut and front motor mount are recent and in good shape. The ability to duplicate this by moving the the gearshift within the extremes of the reverse detent position make the shift cable itself(stretched or out of adjustment) a great place to start my investigation. I will check its condition,,clean all connections, and perform another drain and fill. She's resting at home while I'm on vacation, and I'll post my comments once I get into the repair later this month....Steve

koolhandluke · Post by **koolhandluke** » 15 Jan 2022, 06:58

Sharing the results of my tinkering with this when I could over the last couple of months. Shift cable did not appear to have any play, so I experimented with adjusting it by tightening the threaded plastic end piece 1 turn, then 2 turns to account for any stretching of the cable. I seem to have found a spot where moving the the shift lever within the reverse detent position no longer caused it to jump out of gear. I still set a TCM 0039 code with a flashing arrow, so I disassembled the PNP switch( per the great MVS writeup)cleaned out the dried grease, stretched the springs and renewed the copper contacts. Lubricated it with some fresh dielectric grease and reinstalled it. I was able to do this with the switch body in the car to avoid the step of breaking down the harness. It's been a few weeks now, and none of my issues have returned. Thanks to all for your suggestions and input.
Steve