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Overdrive Quit Working

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PAUL161

PAUL161

Great Pumpkin
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We went to Haps gathering yesterday at Kershaw, SC. On the way the OD starting acting up, it didn't want to engage for a long period when up to speed, like 5 or 6 miles. Just before we got there it quit all together. We decided not to take it on the track, (Bummer), not knowing how serious the problem was, so we left early and limped back home, well, not actually limped, just didn't have the OD and not knowing what was wrong, didn't want to put much pressure on it. I checked the electrical and juice is going down to the interlock switch on the transmission, but don't know if the switch is working. I'll put it up on jacks today and go underneath to investigate further. The solenoid might be sticking, don't know why, as the oil was changed about a month ago. I was thinking about putting in some ATF to see if that would help, but decided to unbutton the solenoid and inspect it first. Update coming later. PJ

PS, Question, is there a place on the OD unit where an oil pressure check can be made, if so, what's the procedure? PJ
 
Take it out for a drive and flip the switch for the OD. Then hold pressure on the gearshift lever to the right. It might just be that the switch is sticking. Try this and let us know.
Vince
 
Paul

I've had trouble with the sw itself. My TR6 will act intermittently. I wiggle the sw around and o/d will kick in and work. The unit itself is usually pretty trouble free. Good luck

Marv
 
Hi Paul;

Your 72 should have the same OD switch as my 74 i would think,The wiper /overdrive switch?
Mine was giving me trouble until I figured out that the steering column cowl was slightly out of place and restricting the movement of the switch arm and not allowing it to make full contact at all times so it would be intermittant.
Sounds like it may be deeper in your case but might be something simple like that. Good luck


Mark
 
The ball switch on the trans gets worn after awhile and then does not make proper contact. I wound up replacing mine. Bit of a job getting your hands up in there.
 
Well here goes. I checked the switch and the wiring down to the solenoid and there's 12 volts going down there when it's in 3rd and 4th gear, so I'm assuming the switch and the interrupt switch is working ok. Notice I said "assuming"! I dropped the solenoid down and the center rod/piston was sticking a little. Cleaned everything up, put it back together and the OD still will not drop in. I'm now wondering if the solenoid went bad. I'll pull it out tomorrow and bench check it. A fellow mentioned on another forum that the ball might not be seating properly and tapping it in the seat might help it seat better. Thanks for all the input. <span style="font-weight: bold">I really appreciate it!</span> This is the first time it messed up since I rebuilt the engine and transmission in 2006. Believe it or not, the car has only been driven 1100 miles since then. PJ
 
After I replaced my switch it worked great for about 600 miles then stopped again. Turns out it was the o-rings at the solenoid. About an hour and $12 and I was on the road again.
 
Vince, I just got back with the B and the OD is working fine! Found out the plunger was sticking. It wouldn't drop out with the plate off and I had to pull the solenoid down, use a straight dental pick and push it out enough to get my fingers on it and pull it the rest of the way. It was gummy on the lower side. Cleaned it and polished it up a little, tapped the ball in the seat a little as per John Weimers instructions and it is working fine. I thought I had it out when I rebuilt the transmission but remembered I never did. Somehow the job of doing that got lost in the sauce somewhere. CRS I guess! Thanks for your input, it was much appreciated! Made the wife happy so it was worth the aggravation! :jester: PJ
 
Always a good thing when it all works out in the end with just a little cleaning.
 
Vince, How's the TD coming along? PJ
 
Slowly. It's temporarily being used as a mock up for an automatic conversion. A friend was contacted by a TD owner and she wants her car to be automatic. I've offered my garage and help to get the job done. I know it's somewhat MG blasphemy but she's own the car since she was 16 (1960) and does not feel confortable shifting. At least she can enjoy it for a few more years. We're trying to do it with virtually no modifications that cannot be reversed. So far so good.

My TD - I pulled the engine to change all the rubber bushing, seals, mounts and that turned into tearing most of the engine down. I replaced the bearings, all the gaskets, new MOSS crank seal and speedisleeve. She's all back together. I've been trying to pick up a spare trans to use in lieu of my unknown condition trans. Wiring is all ripped out, dash re-done, 1 rear spring rebuilt.....I was all over the place with it and then took on a '65 project for a club member. Then decided to help out with this project.....My plate is full for sure.
 
Looks like boredom has no room to breed in your house! It's nice of you to give your time and work space to help this lady with her car. Rewarding I'm sure. Good for you. Says a few things about a mans character. :smirk: PJ
 
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