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Update on my AW71 OD problem.
As most of you know from my previous posts I had a problem getting my ’93 944T to shift reliably into 4th. Commonly this is referred to as an OverDrive problem even though this is not an over drive. It is an electric controlled shift between 3rd and 4th gear of this transmission. It is not like the over drive I used to have on my 1981 242GT which was a standard box with switch on the shifter enabling me to drop the ratio after you were in 4th, hence dropping RPMs and therefore increasing gas mileage and engine life.
We all know that it can be either the solenoid  , the relay tucked away deep behind the center ashtray, or the shifter switch and any wires in between.
I had changed out all electrical components, checked for continuity, flushed professionally and by myself with Mobil I, and all to no avail.
Then somebody mentioned that IPD offers a “blank-off” plate to replace the solenoid for a lot less money than what I already had spent.
I found out that the only thing this plate does is enables the hydraulic fluid to run from the center hole to the aft hole on the tranny. I used a Dremmel (high speed rotary tool) to grind a channel   in my old (still working) solenoid, I had previously replaced this one with a Volvo new one. The steel of the solenoid is pretty hard and it ate up two 1/8” tools quick. If you can mill it or have it milled it would be better, I used a drill-bit also and it works.
I proceeded to take the new solenoid off the transmission on the driver-side but ran into some problem. I took a closed end wrench heated it up and put a 30 degree bend into it in order to reach up as the drive tunnel does not give you much room.
I tried a regular and deep 12mm socket with ratchet on the ‘frozen’ bolt and therefore had to take off the shift linkage  . Taking this one nut off to release the linkage made it a lot easier to work the ratchet in the tunnel.
With my luck though, I still could not loosen it and had to drop the tranny center support to get better access.
I also bought a 12mm gear wrench which is the tool of choice for this job especially if you can get one that has a “knee” end. I took the “new” solenoid off and just unplugged the electrical connection just under where the wire enters the top of the tunnel. Took some drill bits the size of each hole in the solenoid and turned them around in the holes of the tranny to make sure they weren’t plugged. (Be careful as the bits can fall in)
 Mounting everything is the reverse of the above. Except you don’t have to worry about wires and were to fasten/support them to keep them from chaffing as you don’t need them.  I put in a new outer O-ring and opted not to use the inner O-ring as you have to cut that one in order to leave a space for where you cut the channel (C-ring), just leave it out (no problem aligning it)
After remounting everything I started the car and drove her away, she shifted beautifully and smoothly through all 4 gears. Hurray what a pleasure. The car is mine again and the kids has to ask me to drive it when they are home.
I parked the new Town & Country and now use the Brick as my daily driver (40 mile) commute.
My advice to anybody having an OD problem with their automatics; forget about the $140 solenoid, the $45 relay, the Switch, the dashboard light and all the work involved checking/replacing these units. DO WHAT I DID
Take the solenoid out, cut the wire off, grind a channel, and put it back in. From start to finish this is a 3 hour job that saves you a lot of headaches.
Low and behold when I want to pass or accelerate quick I just give some gas and the automatic knows to shift back to 3rd or even 2nd with the kickdown, hence it is an automatic you should not have to shift it to 4th or 3rd .
Sorry about the rambling on but this problem had been bothering me for a long, long time and the solution is so simple and cheap unless you are an aficionado that wants to keep the car in showroom condition and working order. I just want to drive it and see if I can get 465K miles on it like my 123S I used to have.
Thanks to all that gave me input and inspiration the Brick is no longer for sale.
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EJO now a 1994 940T 190K; ex '65 123S; ex '75 245; and ex '81 242GT; also Chrysler 2002 T&C and 2006 MINI Cooper
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"Commonly this is referred to as an OverDrive problem even though this is not an over drive. It is an electric controlled shift"
Nice post and sure to help a lot of those who don't want/need the controlled downshift. But as Illbird says, you are mistaken about the AW70/71 gearing.
It is a 3-speed plus overdrive, as below:
!st gear = 2.45:1
2nd gear = 1.45:1
3rd gear = 1:1
OD...... = 0.69:1
Overdrive is a function of gear ratio, not where the relevant gears are located. The AW70/71 OD is accomplished internally, where your 4-speed M46 had an external OD unit mounted outside the gear box.
The Manual 4-speed OD also operates the same way as does the AW70/71 — by using a switch and relay-controlled solenoid to hydraulically activate the OD engagement.
The only difference is that the Auto tranny OD relay is automatically energized when the car is started, so that OD engagement is automatic — whereas the 4-speed's initial OD engagement requires manual switch/relay activation.
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Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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as for your comments about your car not having an overdrive...false
overdrive simply refers to any overdriven gear...which means that the output rotation is greater than the input rotation aka mechanically disadvantaged...generally the last gear in modern cars is over driven, but in the case of some 6 speeds the last two gears are "overdriven" hence then need in a c5 or c6 corvette to shift from 6th to 4th to really put the coals to her the T-56 is overdriven in both 5th and 6th. that being said the AW71 is a 3 speed auto with a 4th gear that is overdriven. yes it is not an external system such as the old Doug Nash units or the modern Gear Vendors units, but I assure you 4th gear is overdriven and thusly considered overdrive (output rpm is over that of drive rpm). the last car that I was in that didn't have any overdriven gears and hense no overdrive was my 68 firebird which has the all-mighty General Motors built TH400 3 speed in which the final gear (3rd) is a direct ratio or ...1:1 after having that pig for many years as a daily driver....and this was in the mid 90's...i cannot understand why anyone would forego repairing the overdrive if they do any driving at all on the highway....you will pay for the cost of the repair in fuel several times over...not to mention the reduction in engine life....now that that is all done with ...interesting post regarding the block off plate...
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Point taken but I don't think the ratio is that high as in most European cars with lower HP and torque they keep the rpms up to stay on top of the power curve. In my case driving 75 mph @ 3,100 rpm is acceptable in 4th but not 4,000 plus rpm in 3rd.
My Chrysler 4 speed auto runs 2,200 rpm @ that speed with a torquier 6 cyl. engine and my 5 speed manual Cooper runs 3,300 rpm and the Cooper S 6 speed manual does 2,800 rpm.
All a question of torque & HP to move the vehicle and most cars in Europe (not sooped up) therefore have those type of ratios and most can't put out enough to be engine efficient, hence not to much over-drive.
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EJO now a 1994 940T 190K; ex '65 123S; ex '75 245; and ex '81 242GT; also Chrysler 2002 T&C and 2006 MINI Cooper
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" Point taken but I don't think the ratio is that high..."
I can't speak to your "that high" opinion except to say the the OD 0.69:1 is the published ratio for the AW70 with 3.73:1 rear end in the 1986 240 Owners's Manual.
My '93 940 manual says that your 940T AW71 is the same. My 940na too, but with a 4:10 rear end.
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Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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Okay, Sorry to all about the mis nomenclature of the 4th gear and OD by myself. All I'm trying to say is that the ratio without the OD is unacceptable in daily driving unless you drive Downtown NY, Manhattan, Chicago, Rome, Barcelona, London and the likes, where you never ever can get over 55kph or 35mph. Your 3 speed auto is fine. When you get on backroads and or highways you need the OD and as I'm in a car with an automatic it should do this automatically and I should not have to shift between 3rd and OD or vice versa.
If I have to shift I will drive a car with a real (manual) transmission which I like better anyway.
I was just showing readers that there is a cheap solution (cost no money) to get the constant use of the 4 gear ratios available in this automatic transmision without having to worry about any electronics, which 99.9% of the time seem to be the problem.
Again to all yes I do agree that when the ratio of engine to tranny output is greater than 1 it is an overdrive situation except in manual transmissions we called it top gear being it 3, 4, 5, or 6. We call them 6 speed manual transmissions even if the 6th gear ratio is 0.XX : 1.
Everybody enjoy your Over Drive but when mine shifts from third I'll still call it shifting into fourth no matter if it has an OD ratio.
Thanks,
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EJO now a 1994 940T 190K; ex '65 123S; ex '75 245; and ex '81 242GT; also Chrysler 2002 T&C and 2006 MINI Cooper
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Brilliant: to the FAQ. A question: could you remove the stuck bolt using a 12mm "stubby" short gear wrench sold by Sears?
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No I tried, my friend lent me one to use it did not work. I finally got it loose by preheating bolt only and applieg a vise grip wrench set with waterpump pliers. Let it cool and then applied heat to the aluminum (tranny) underneath.
I did not use acetylene torch on the casing just a propane torch.
The vise-grip did the trick and a new 8mm bolt for mounting.
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EJO now a 1994 940T 190K; ex '65 123S; ex '75 245; and ex '81 242GT; also Chrysler 2002 T&C and 2006 MINI Cooper
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