• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Overdrive

Share this page

D

Donny_L

Jedi Trainee
Offline
My OD doesn't engage when I hit the switch but I know that it does work. While taking a test drive with the transmission tunnel off I hit the switch and nothing happened. Then with the switch still on I reached over to the little lever on the passenger side of the transmission and with a little push of my fingertip, it kicked in.Do you think a new switch and silanoid will fix her up?
 
-Nope you still need afactory manual which will tell you how to set up that little lever properly it is maladjusted.--Keoke---- :laugh:
 
LOL You crack me up Keoke!! Is that going to require me to open up the guts of the trans&OD? If thats the case I don't think I'll ever have a working OD
 
Donny_L said:
My OD doesn't engage when I hit the switch but I know that it does work. While taking a test drive with the transmission tunnel off I hit the switch and nothing happened. Then with the switch still on I reached over to the little lever on the passenger side of the transmission and with a little push of my fingertip, it kicked in.Do you think a new switch and silanoid will fix her up?
Click to expand...
A very frequent problem and it is caused by a weak solenoid. You can hear it click but it won't move. I had a very similar problem and fixed it by installing a new solenoid. I did not measure the amp draw on bad versus new so I can't give you those figures.
Patrick
 
If it's adjusted by tinkering with the switch under the hood, I've made that adjustment more than a dozen times,following the step by step instructions in the book. I'm pretty sure I got that right.
 
Speaking of overdrives, how does one insure that one never destroys his overdrive when backing up ?
 
No, Keoke is talking about the lever that the solenoid lifts up. It is accessible from the side cover (driver's side of the transmission). There is a procedure to adjust it.
ODSolenoidleverarmadjustment.jpg


You could have a weak solenoid, but the adjustment is easy and free. Try that first and if it doesn't work, then replace the solenoid.

The procedure is available from British Car Specialists. It also may be in your repair manual.
 
Just make sure the shift lever switch is working (with the ignition on and the main OD switch on, you should hear the solenoid click when the shift lever is pushed to the right and "unclick" when the lever is returned to the center). The switch allows the OD to engage only when the shift lever is pushed to the right of neutral (away from 1st, 2nd, and reverse).
 
1) Design - there is a switch by the gear lever that only allows the O/D to be used in 3rd and 4th
2) Technique - I always flip the O/D off when decelerating to a stop (else it will kick in when you may not want it when upshifting). If I forget, see #1
 
I read a thread in the Triumph section wherein the fellow claimed that due to wear internally sometimes the operating valve setting lever had to be set past it's normal 3/16 bar insertion placement. What do you think of that? Not that i am suggesting this for Donny.
 
:thankyousign:

Keoke----------- :wink:
 
I'm not sure about that. I'd be cautious because the solenoid pull-rod has to travel all the way up to the top of the solenoid cylinder to turn off the high amp circuit that draws the pull-rod up, and activate the lower amp holding circuit. If it is misadjusted, it would quickly burn out the solenoid or blow a fuse.
 
It coul be a weak solenoid or out of adjustment operating lever, but since "I flipped the switch and nothing happened" with the trans cover off it also could be a bad switch or wiring problem, I woould check this before I start buynig parts, operate o/d with the engine off but iginition on, tunnel off, click into od in 4th, solenoid should at least try to click, make a little jump or noise, then shift into reverse and it should click again. If it doesn't something isn't getting juice or the solenoid isn't just weak, it is dead
 
I got your back, Keoke!
grin.gif
 
My switch musta been messed up when i destroyed mine. I replaced it and the solenoid when I slid a used replacement onto my tranny ." Slid " may not be the right term as I remember it involved compressing a number of springs only to find that the cam was in the wrong position and had to be realigned in order to bring the trans. and overdrive together. I have since seen a thin wire used to keep said cam in place. It worked fine when i was done after I reset the the operating valve and throttle switch. Thanx for the info. Bob, Elrey
 
I do hear the click when in the garage with the ignition on and engine off. On the road at speed I could not hear it because of all the nois. Especially with the trans tunnel off. By "nothing happened" I meant that it didn't drop the RPM untill I helped it out by moving that lever on the psngr side of the trans.
 
If you hear the click, you have electric power, so it is down to the lever travel which is controlled by the solenoid pull-rod travel and the adjustment of the left-side lever which is connected to the right side manual lever by a rod. A weak solenoid will click, but not pull all the way up; a misadjusted lever will not travel far enough to lift the ball valve to release the oil pressure in the accumulator to move the OD cone into place.
 
Hi Donny,

A couple of quick thoughts. Can we assume that the OD was working prior to your recent problem discover? Have you examined the solenoid to make sure it is dry (no oil fouling the piston) and that the rubber bumper is still in place below the piston?

If you have recently changed the oil and used a synthetic (ie Red Line MTL), it is not unheard of for the oil to escape into, and flood, the solenoid chamber. This, of cause, would only be a problem if your OD has a cover plate sealing the solenoid compartment.

Also, a small rubber piston bumper is fitted below the solenoid to stop the piston from extending further than the solenoid can retrieve. If for any reason this is not in place, the piston probably will not recover and the result could be a burned out solenoid.

Good luck,
Ray (64BJ8P1)
 
Can the solenoid get stuck in the ON position? Last question for awhile. Going back to watching and learning. Thanx, Elrey
 
There is a spring that pushes down on the ball valve that the solenoid lever lifts up. So the solenoid has to overcome spring pressure to go up. Spring pressure and gravity would tend to bring the solenoid pull-rod down when the electro-magnet circuit that holds the solenoid pull-rod up is turned off.
 
Back
Top