I've been turning wrenches for 50 years, but I just bought my first Volvo, a 1996 960 wagon. It only has 105K on the odometer,but the second owners sold it to me cheap because the transmission was "slipping" in first. What is actually occurring is it's starting out in second gear, though occasionally it does start in first. It also doesn't downshift when I hit the gas. I replaced the transmission fluid, the old fluid was dark but had no traces of metal. My experience working on auto transmissions is limited to oil and filter changes, or total replacement. Your thoughts and comments will be greatly appreciated!

There are a number of stories on this BB about transmission issues with the AW30/40 trans due to misadjustment or failure of the PNP switch. (I believe that stands for "Park-Neutral Position"). The switch is located on the exterior of the trans and is replaceable - at considerable cost and hassle. The trans is electronically controlled through its own dedicated module and PNP problems can affect everything it does.

That said, the easy and cheap first step is a fluid flush. Synthetics are fine, but the latest Dexron fluid specification is Dexron VI, which is cheaper than synthetic and much superior to the stuff Volvo spec'd back in the 90's (Dexron III). Dex VI is compatible with all earlier Dexron fluid specs.

The AW30/40 will pump out the fluid much faster than the old AW70/71 boxes, so be prepared for that and a quick jump to the ignition switch. Again, see the 700/900 FAQ section for procedure.

Try using the search function in the upper right corner of this page for "PNP Switch" and look in the drop down menu at the top of this page in the "more" box for 700/900FAQ's. Plenty of info in there on this trans.


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Bob: Son's XC70, my 83 244DL, 89 745 (Chev LT-1 V8), 98 S90 (recently sold) and 2010 XC60. Also '77 MGB and four old motorcycles

Ok, I drained the tranny again, pulled the pan and filter: the filter wasn't very dirty, pan was clean, no metal of any kind. Replaced the filter and gasket, filled back up with DexMerc, tranny is pulling better, but still no cigar. When I start it in low with the tranny on Economy setting it pulls much better. When I start out in Drive the torque converter slips and it seems to not change gears, like it's stuck in third gear or overdrive. I'm thinking this is a purely electrical problem, so I'm going to check all the connections between the tranny and engine. I may also buy a used transmission module if that fails. Any thoughts?

AND I have an error code on the OBD, P1618. I read that was a code relating to the TCM.The plot thickens....

Just ordered a new PNP switch, in case I need it....

My 1998 S90 had three modes on a little panel beside the shift lever quadrant. I don't 100 % recall the letters but IIRC they stood for Sport, Economy and Winter. Sport is supposed to keep the car longer in a gear before upshift and to kickdown quicker for passing power. Economy is normal operation. Winter started the car off in third gear - which is actually a 1:1 ratio - to reduce torque to the drive wheels in low traction conditions. I recall a note in the owners' manual to avoid extended use of the W mode in case it causes transmission overheating.

If you have selected a mode other than "W" and the car seems to pull away sluggishly in a high gear, that switch assembly (or the TCM) may be the problem.
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Bob: Son's XC70, my 83 244DL, 89 745 (Chev LT-1 V8), 98 S90 (recently sold) and 2010 XC60. Also '77 MGB and four old motorcycles

I keep it in E almost all the time. If I start in L or 3 it drives pretty good, but I still think it's starting in second. I just went underneath the car to clean the three electrical connectors on the driver's side of the transmission. The aft connector does not want to come apart, it's as if the pins are fused by corrosion, which doesn't surprise me since it's open on top! So I soaked them all with CRC-6-56, and try them again tomorrow. Does anyone know where the TCM is on the 960? Can't seem to find it...

My Volvo wiring diagrams for the 960 indicte the TCM is located above the driver's knees beside the steering column. Has about 30 wires going in to its plug. Three wires connect the "mode selector" (Winter/Sport, etc.) to it: Brown-Orange, Grey, and Grey-Red.

It is very rare for these electronic units to have a problem...it is nearly always bad connections or a failed or misadjusted mechanical component such as a switch, solenoid, etc.
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Bob: Son's XC70, my 83 244DL, 89 745 (Chev LT-1 V8), 98 S90 (recently sold) and 2010 XC60. Also '77 MGB and four old motorcycles

Just installed a $45 salvaged TCM, now the transmission is working great! I'll save the PNP switch for a rainy day, but I will install the salvaged mode switch when it comes in tomorrow (mine is broken, won't go into W). Thanks for the input VolvoDad, Andrew and JWalker!!

Volvodad, I think you're on to something: The "W" button will not engage and light up, and the transmission in D is starting in third then shifting to overdrive. I'm going to pull that switch out and see what's up. Does it come out from the top, or do I have to go under the car?

Here is the page on AW70 transmissions.

https://www.brickboard.com/FAQ/700-900/TransmissionAuto.htm#ATFluidNeedsChangingLateorPoorShiftQuality

In just browsing there, you may have a clogged filter. There is also on the same page the procedure for changing ALL the fluid, including that in the torque converter.
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"Do you think that's air you're breathing now'? (The Matrix 1999) '94 940T (463K+), 92 245 (300K+), 90 740 (148k)

The tranny might very well have a clogged filter but if your car is a 96 960 then it doesn't have an AW70. It has an AW30. A good place to start is with a thorough fluid flush. That can solve a lot of problems! Consider cleaning the filter (if it has one) then flushing with the cheapest fluid and refilling with synthetic ATF. Synthetic has worked wonders in my cars...:)

https://www.brickboard.com/FAQ/700-900/TransmissionAutoAW30.htm

https://www.brickboard.com/FAQ/700-900/TransmissionAutoAW30.htm#96090FluidFlush

Sorry bout that! Guess I have 940 on the brain! 😀
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"Do you think that's air you're breathing now'? (The Matrix 1999) '94 940T (463K+), 92 245 (300K+), 90 740 (148k)

I'm gonna also check electrical connections to the tranny, in addition to the filter and fluid change. Thanks guys!

Good idea! Almost forgot, check for tranny related OBD codes in the OBD II readout.