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View Full Version : Automatic Transmission won't shift into 4th gear, no OD function, 91 940 Turbo


9Shenandoah
04-16-2007, 08:35 AM
On my 1991 Volvo 940 Turbo, the automatic transmission won't shift into 4th gear,and it has no OD function. The linkages are all loose on the transmission ( the bushings were removed by the original owner) despite the car being in very good shape, and though I flush the transmission, I never messed with the linkages since basically they work.
Is it possible the loose linkages cause this problem? Sometimes when I pull over on he highway, and I throw it into R and then back into 2 and then D, the 4th gear and OD work like a charm.

--Could this be the OD relay?
--Could this be something else, like dirt in the transmission ? Happened on my Corolla 88 after I did a flush( if so, what)


Automatic Transmission won't shift into 4th gear, no OD function, 91 940 Turbo

mr.volvo
04-16-2007, 08:39 AM
most likely suspect, overdrive relay. what happens when you activate and deactivate it with the switch? does the arrow on the dash come on?

Lockpixor
04-16-2007, 08:52 AM
Did the overdrive fail recently or have you never had 4th gear? Regardless, I'd pick up an OD relay from eBay or one of your friendly turbobricks car recyclers, its bound to fail eventually. In the mean time I'd pull out the relay and put it back. It could just be a bad connection.

Good luck

Three Fat Tigers
04-16-2007, 04:32 PM
If the dash light turns on/off with the shifter switch, odds are the relay is fine. Dirt would be very unlikely. Most 740/940 OD issues are caused by the OD relay, OD solenoid or the kick down cable.

The shifter linkage bushings might be a factor, they are cheap and easy to install, and boy do new ones make the shifter feel nice. I had missing bushings in my '94 944T until recently, though it had no effect on the operation.

With the ignition on, engine off, lean down as far as you can out the driver's door while repeatedly pushing the button on the shifter (or have someone else do that), you should be able to hear the solenoid clicking under the car. If not, odds are the solenoid is bad and you'd want to verify that there is power reaching the solenoid under the car. Next you could pull the solenoid off the car and bench test it, apply 12V+, should clearly hear it clicking.

Also check the kick down cable, try adjusting it to allow more slack. Maybe remove it from the throttle and pull it a few times to make sure it feels like it's working properly and not sticking. Most likely if your car is up-shifting and down-shifting at the normal shift points, this cable is functioning correctly as well.

If you do hear the solenoid clicking and you think the solenoid is fine, and you don't think the kick down cable is a factor, fluid level is normal, I'd start with the shifter bushings, then try bypassing the OD solenoid anyway.


Tips:
If removing the OD solenoid, jack up the entire left side of the car to prevent trans fluid from coming out. Clean the area around the solenoid first with brake cleaner or similar. 12mm flex head ratcheting hand wrench is the optimum tool. When replacing/reinstalling, use new o-rings (odd sizes, so Volvo or fcpgroton.com), or apply RTV to the old ones.

New these are kinda pricey (ebay may have the best price, also don't expect it to come with new o-rings), used are hit an miss but should be very cheap, but I've also found new ones to be flaky from time to time as well. Same solenoid is used on all red block RWD automatics from at least '83 to '95.

Bypassing:
It only takes a couple of minutes to bypass, just take a drill, the bit about the size of the larger hole on the bottom, place the solenoid in a vise at an angle, or just drill at an angle, starting from each hole, drill toward the opposite hole. The channel you make doesn't really need to be deep, the metal is soft so it doesn't take much work. You won't need the smaller o-ring anymore.

For reference:
http://www.threefattigers.com/Protocore/Volvo/ODsolenoid-1.jpg
Objective is to remove some of the metal as indicated by the colored lines:
http://www.threefattigers.com/Protocore/Volvo/ODmod1.jpg
From a 240, but the trans/solenoid are the same:
http://www.threefattigers.com/Protocore/Volvo/ODsolenoid.htm

If after all that, the OD still doesn't work, I've heard of a spring inside the trans that can be removed and stretched out to possibly solve this issue. But this would be an exceptionally rare issue, and it's a procedure that I'm not familiar with.

Slowcars4life
04-17-2007, 08:47 AM
I'm having the same problem, but my OD light works. The OD kicks on after about 15 minutes of driving. I just had the trans replaced too.

Three Fat Tigers
04-17-2007, 04:09 PM
I'm having the same problem, but my OD light works. The OD kicks on after about 15 minutes of driving. I just had the trans replaced too.
Did this issue exist on the old transmission? Is the fluid level normal?

Could be a weakness in the solenoid, or it's power supply. You might check under the car with a test light.

765tiME
04-17-2007, 07:02 PM
Maybe they re-used a marginal solenoid?

Mine's the same way, needs to get hot before it starts working, and in this weather it can be up to 1/2 an hour...

Slowcars4life
04-18-2007, 10:53 AM
Did this issue exist on the old transmission? Is the fluid level normal?

Could be a weakness in the solenoid, or it's power supply. You might check under the car with a test light.

No, the old trans shifted into OD fine and the fluid is fine. I just have not had a chance to see if anything is loose down there. It is annoying as hell going 60 and being over 4000rpms

HonestJhon
04-18-2007, 02:35 PM
in my 91 940, the light would come on, the solenoid would click, but it wouldnt engage 4th.


took the solenoid off, found it was missing one of the orings (the inner one)
replaced it, still wouldnt work.

took the relay off, with the car jacked up, and some cardboard on the ground, ran the car for 5 seconds, and it hosed out whatever was blocking the passage.
wiped it up as good as i could, put the solenoid back on, and its been great since then.

MrDoug
04-18-2007, 02:43 PM
Mine is just the opposite-goes into OD fine when cold,but once it warms up, it jumps out of OD into 3rd- not fun on the highway with 4.10 gears