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OD barn burner...

espbassist88

New member
Joined
Mar 13, 2016
Location
Gaston, SC
Alrighty. ..I have hit a major headache. After rebuilding my OD, it does WORSE than it did before. Pressure before the rebuild was about 450. When cold, it worked flawlessly but when warm, you can forget about using it. The pressure now sits at 250. I used the IPD kit. I was so sure that I had my OD fixed but I've somehow managed to make it worse. I think my next move is to replace the solinoid with another one I have, and to check my releif valve. Anyone have another ideas? I have the J type overdrive. It's from a 1986 740 Turbo. M46 trans. Any help is appreciated!
 
Tell us exactly what you did for the rebuild. Replace the piston seals? Open up the PRV? What position did you set that little (pump pressure) piston on its eccentric? Which fluid? Does the solenoid rattle when you shake it?
 
I did replace the piston seals. I did replace the Pressure Releif Valve orings. I'm fairly sure I added the shims back as well. As for the pump, I'm not quite understanding that question. Not sure about the fluid because my mechanic was replacing some bearings in the main trans so I had him remove the OD so I could rebuild it. He reinstalled it, an the trans as a whole. I don't recall the solinoid rattling. I did test it before reinstalling. Im going to look into it alot more this weekend, if I have time.

If you could elaborate more on the pump question, I'll do my best to answer.
 
Using this parts diagram
I am referring to #10, the sleeve for the fluid pressurizing piston. There is a flat and slot to one outer side of the sleeve. The sleeve must be reinstalled in the same orientation with the slot toward the hole the screen fits into in the bottom of the unit. Otherwise the fluid cannot flow through to the passages. Also, there is a check ball and screen (#17, 18) that likes to fall out of place when reinstalling.
ODGIFPartsImage.gif
 
Ahhh gotcha! Im fairly sure the spring and ball are installed. I took my time with it. I do question number 10 however. I didn't know they needed to he lined up. So that REALLY makes me wonder.
 
Well I opened the OD up tonight via the cover on the bottom. I looked at everything. Everything looked normal. The sleeve that goes over the pump piston was in line with the piston's flat. I drained the fluid all together and put in 2.4 quarts of Type "F" fluid. Still no engagement. Not even a sputter like it's trying to. Haven't done a pressure test so im not sure where it's at. Last pressure was at 250. I dont understand it. I really don't want to drive this thing around, doing 60 MPH at 3,000 RPM.
 
I don't recall the solinoid rattling. I did test it before reinstalling.

This is the key. The solenoid can get dirty; take it apart and clean it. Did you replace the solenoid O-rings? You can get a set for less than $10. There is a post on here (if I'm recalling correctly) that details all the sizes.

You can also test the solenoid by turning the key to position 2 with the engine off, shift into 4th, then hit the OD button. Do this with the door open and lean out as much as you can. If the solenoid is working you'll hear it click from underneath the car as you turn it on and off.

As a side note, do you have the solenoid sealing washer? That is vital to retaining all your ATF when you're in overdrive.
 
This is the key. The solenoid can get dirty; take it apart and clean it. Did you replace the solenoid O-rings? You can get a set for less than $10. There is a post on here (if I'm recalling correctly) that details all the sizes.

You can also test the solenoid by turning the key to position 2 with the engine off, shift into 4th, then hit the OD button. Do this with the door open and lean out as much as you can. If the solenoid is working you'll hear it click from underneath the car as you turn it on and off.

As a side note, do you have the solenoid sealing washer? That is vital to retaining all your ATF when you're in overdrive.

WRT the door open, do it from the passenger side. Less likely to hear Dingggg...Dingggg*snap*Dingggg..., etc. Instead you'll be able to hear it snap and pop as it engages and disengages. Typically, just rolling the window down is enough, since it's pretty loud, but not loud enough to avoid being drowned out by either the dinger or the dying cow used on the 1980-83 cars.

On the washer, that's important, as well as not having a hole in the solenoid where the wires attach. Had a pinhole in a solenoid once. Overdrive lasted about 30-40 miles before it didn't really want to go in.

-J
 
I did chage out the o-rings on the solenoid that was in use with the OD at the time of the rebuild. Once I found out that the OD acted up, I changed it out for another one i had. I didn't change the rings on it but I did test it to see if it worked, simply by hooking up the battery to it. It did move but I don't know exactly how much is too little or anything like that. I do have that washer in use as well. The solenoid I was first using does rattle a little when shaking back and fourth. I don't know if the solenoid I am currently using does that or not. I didn't check the rattling before installing.
 
Alright folks...instead of making a new post and kicking a new dead horse, I figured I'd bring an old thread back to life, and kick this one instead.

So since earlier this year (read from the beginning of this post...), I rebuilt my OD Ever since, its worked WORSE than it did before I rebuilt the thing. Yesterday, 10/15/17, I yanked out all the hydraulic components that I could. The high pressure filter, the check valve thing (spring, ball, and plate) under the pump in the center chamber, and the relief valve beside the solenoid. I inspected and cleaned everything that I could. I blew air through all the passage ways that I could find in the OD where the parts mentioned above reside. My uncle came across a questionable o-ring on the smaller diameter cylinder (Part number 21, above part number 24). I replaced that. The seal between that particular o-ring and the larger sleeve it sits in is MUCH better. The relief valve currently has 3 shims, all of which equal to .024". After I was all happy, thinking that we found the issue as to why the O.D. wasn't working for flippin' months, I put everything back together, refilled the transmission, and took it out for a spin. What did I find? That the fudging thing STILL DIDN'T WORK. It wouldn't even try. But the kicker is, is that when I let off the gas pedal, basically letting the car coast, the RPM would drop while the OD was engaged, settling to around 1500 RPM. But when you pressed the gas, it would jump right back up. 3000 RPM at 60 MPH.

Today, I took it back out after I got home from work, just for fun. Probably not even a mile from my house, I got curious, and pressed the OD button and BAM. It engaged! I was stoked. I immediately took to the closest highway and opened it up (dis-engaging and re-engaging the OD along the way). Again, it did perfect at this point. I drove to the next closest town. When I got to where I wanted to turn around at, I dis-engaged, hung a u-turn, and engaged the OD again. Only this time...nothing happened. Total distance from my house to the next closest town is 8.4 miles one way....so its not too long via car.

I got home and hooked up my pressure gauge to test the residual, and the operating pressure. It didn't hit 20 PSI (residual) until around 55 MPH. Operating (OD engaged) was around 300 to 325 PSI. So, with all that said....does ANYONE have any ideas as to what may be wrong? Thanks for reading the story by the way...ANY help is appreciated.

Also, the only thing I have replaced between now and the time of rebuild is the oring mentioned above.
 
Are you sure the solenoid is getting good 12v? Use a test light that draws a decent amount of amps and see if the solenoid wire will light it up good. Kinda sounds like something could be screwy with the relay and electrical side of things... I say that because it worked one min, then the next it didn't... very reminiscent of a shorted connection.
 
I agree with the member above, now it just sounds like electrical issue.
Check ground.
Splice hard wire OD to battery with quick disconnect like wire spade.
You can wire for test purposes outside the car through the door for example.
Hookup multimeter in between.
TEST TEST

Seems like you might not getting enough voltage at high load or possible short/broken wire on vibration/movement.
 
I would pull the relay out of it's connector and re-tension each of the connectors with a tiny little screwdriver. Check the relay solder joints, and if it has never been done, just go ahead and re-flow the solder on each joint. When you are in 4th gear, and you hit the button, does the green "5" light light up on the dash?
 
Fourth gear switches fail. Wires that snake through the shifter fail. Wires under the shifter boot fail.

OP first thing ya do now is snake a length of wire through the shifter and connect it right to the solenoid. Verify that the cigarette lighter has 12 volts to it with a test light that has a burly incandescent bulb. Have her drive the car in fourth while you apply the overdrive for testing.
 
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