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The 3000 Forum

Overdrive Problems

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Muratore Avatar
Muratore Frank Muratore
Holmdel, NJ, USA   USA
I have a1966 BJ8. If I downshift from 4th to 3rd while in overdrive; the overdrive will disengage as the car slows and them engage again as I accelerate or shift into 4th. I am using 30w/ND oil in the trans/od. Any ideas on what is going on and what the fix might be?

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rusty1c Avatar
rusty1c Peter D
Antioch, CA, USA   USA
1961 Austin-Healey 3000 BT7 "RUBY"
1963 Chevrolet C10 "Rusty"
Frank,
Sounds like either the overdrive switch (moss part # 140-470, $9.29) on the side of the transmission is acting intermittent or the bushing (moss part # 031-259, $3.89 or part # 461-115, $17.99 depending on which one you have) on the end of the shifter is worn. If the bushing is worn it can cause excessive movement in the shift lever. When this happens the shifter will engage and disengage the switch which will cause the OD to engage and disengage.
The next time you drive the car try holding the shifter with your hand and putting pressure on it to hold it to the right. Then shift up and down from 3rd to 4th and then back down again while to OD is turned on keeping your hand on the shifter pushed to the right. If the OD stays engaged then the shifter bushing is probably worn allowing for excessive play. I had the same problem in mine and when I replaced both the switch and bushing the problem was solved. Either way it is a quick and inexpensive fix. The switch can be accessed from underneath the car and the bushing can be replaced by removing the shifter from the top of the transmission.
Pete

Muratore Avatar
Muratore Frank Muratore
Holmdel, NJ, USA   USA
Pete,

Your diagnosis is correct. Just took the Healey out this morning and performed the "test" you suggested. Sure enough, as I downshifted into 3rd with the o/d engaged and held the gear lever up and to the right the o/d remained engaged. If I let it lose and allowed it to move around the o/d disengaged. I could literally turn the o/d on and off using the gear lever. Will order the bushing and repair ASAP.

Thanks for your advice and suggestions.

Frank

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rusty1c Avatar
rusty1c Peter D
Antioch, CA, USA   USA
1961 Austin-Healey 3000 BT7 "RUBY"
1963 Chevrolet C10 "Rusty"
Frank,
You might want to get another switch at the same time just in case.
Pete

Muratore Avatar
Muratore Frank Muratore
Holmdel, NJ, USA   USA
Hi Pete,

Yes, I'm pretty sure the switch is good but I was going to order another one just in case. Again, thanks for the spot on advice.

Frank

rusty1c Avatar
rusty1c Peter D
Antioch, CA, USA   USA
1961 Austin-Healey 3000 BT7 "RUBY"
1963 Chevrolet C10 "Rusty"
You're welcome.

Randy Forbes Avatar
Parrish, FL, USA   USA
1957 Austin-Healey 100-Six
1999 BMW M Coupe "Blue Car"
1999 BMW M Roadster "Black Car"
2001 BMW M Roadster "Gray Car"
Back in the 80s, we'd shim out the selector switch to get it *just right* so if you put a little pressure on the gear lever to the left, you got a sort of "kick-down" (disengaging overdrive) to pass someone, then let go and have it shift back into overdrive. Just took a little less effort than flipping the dash switch and tickling the throttle linkage switch.



Of course, we were just using them as cars back then too, and for a number of years, the Healey was my most dependable daily driver. I'd leave it parked at offshore supply bases along the Gulf of Mexico for a week or two at a time, while I flew out to work on natural gas production platforms. I made service calls to land-based oil/gas producing facilities in it on a regular basis too (the 2-seater with its big trunk could hold a lot of tools and parts winking smiley ).

Some years later, I was using an MGBGT as my service vehicle, and in plants, it could fit into any area that their Cushmans and golf karts could get through!



As I got older, my service & support vehicles tended to get a little more plush, including this one, a 1999 M Rdstr (the spiritual evolution of the Big Healey):



And its "GT" counterpart (this '99 BMW M Coupe just happens to have a twinscrew supercharger fitted); I still make them sing for their supper!



[/side-tracked]

Muratore Avatar
Muratore Frank Muratore
Holmdel, NJ, USA   USA
Hi Randy,

I was thinking how convenient it would be to leave the old bushing and use the gear shift to "downshift" from 3rd OD to 3rd. Guess you had the idea a long time ago.

Randy Forbes Avatar
Parrish, FL, USA   USA
1957 Austin-Healey 100-Six
1999 BMW M Coupe "Blue Car"
1999 BMW M Roadster "Black Car"
2001 BMW M Roadster "Gray Car"
Yes, I got the idea from then local Lafayette, Louisiana Healeyite Layne Perkins, and no telling where or when he heard the tip.

Best part for you, is that yours is already set up__you don't have to do anything! Well, until it starts disengaging on its own, exceeding the desirable limits of wear winking smiley

dkgraber85 Avatar
dkgraber85 Darin Graber
SLC UT, USA   USA
Hello all -

Had the same issue but turned out to be the lockout switch. Replaced it 3 TIMES using the switches from Moss. Chinese junk I think. Came across an old original Lucas switch and put it in after the third failure, and haven't had an issue since. Since FYI..

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