1955 manual won't shift into overdrive

[Vicegrips85]

1955 Tbird just had the 292 pulled and replaced. Transmission is manual with overdrive. Transmission never left the car... maybe at most it moved an inch up and down during engine R&I. Everything went together great except now the car wont shift into third/OD. Information (even in the technical manuals) is extremely limited on these manual transmissions with overdrive. I've adjusted the clutch and pedal in search of obvious solutions... nothing. Any suggestions for resources or advice on where to start troubleshooting for a diagnosis?

 

[Ward 57]

1955 Tbird just had the 292 pulled and replaced. Transmission is manual with overdrive. Transmission never left the car... maybe at most it moved an inch up and down during engine R&I. Everything went together great except now the car wont shift into third/OD. Information (even in the technical manuals) is extremely limited on these manual transmissions with overdrive. I've adjusted the clutch and pedal in search of obvious solutions... nothing. Any suggestions for resources or advice on where to start troubleshooting for a diagnosis?

If I understand correctly, there was a cable from the dash to the overdrive to engage it plus there was an electrical component that may have been missed in connecting everything back up.

 

[Mark R]

1955 Tbird just had the 292 pulled and replaced. Transmission is manual with overdrive. Transmission never left the car... maybe at most it moved an inch up and down during engine R&I. Everything went together great except now the car wont shift into third/OD. Information (even in the technical manuals) is extremely limited on these manual transmissions with overdrive. I've adjusted the clutch and pedal in search of obvious solutions... nothing. Any suggestions for resources or advice on where to start troubleshooting for a diagnosis?

 

[Vicegrips85]

If I understand correctly, there was a cable from the dash to the overdrive to engage it plus there was an electrical component that may have been missed in connecting everything back up.

Thanks, it appears the OD cable is in tact (it was not removed during the engine swap). It's like after depressing the clutch there is a secondary condition that has to be met for the shifter to "lock in" to third. I have read somewhere in the forum that the car must be traveling 24-30mph to enter OD, is this true of third gear as well, would that be the electric component you mentioned, maybe a solinoid?
Right now its like the shifter half way goes into third then when I release the clutch it springs back to Neutral.

 

[Mark R]

Are you saying the OD won’t kick in at 27mph while driving? Just removjng the motor from a OD transmission should not affect the OD performance mechanically. Im guessing something in the OD circuit did not get reconnected. The obvious and really the only OD electrical connection to the engine/ignition is the OD relay to coil wire. Make sure that circuit got reconnected correctly. Then check all the OD components in the engine bay for proper connections just in case something got unplugged during the engine removal.

Before doing anything major mechanically, checkout the circuits thoroughly. If it worked before the engine removal, it should continue to work now. My money is on wiring.

 

[74 Harley]

Full stop!. You're saying that you can't shift into 3rd gear? There's no secondary requirements to hit 3rd gear. I sounds to me like your shift linkage got knocked out of alignment or bent during the engine r&r.
Figure this out first and the overdrive will probably follow. Go back to whoever worked on the car...

 

[Mark R]

Full stop!. You're saying that you can't shift into 3rd gear? There's no secondary requirements to hit 3rd gear. I sounds to me like your shift linkage got knocked out of alignment or bent during the engine r&r.
Figure this out first and the overdrive will probably follow. Go back to whoever worked on the car...

If you’re saying you can’t manually, physically shift into third, I agree with Harley. Check the linkage first thing.

 

[jack-in-sac]

Before anything else get the shifting straightened out. Whoever did this work for you should not have let the car out of their shop. if it was not shifting correctly after their work and it was correct before their work they need to make it right with you, What kind of repair shop was this? Is it a general repair shop or one that actually knows how to work on pre-electronic modern cars?
Check relay fuse and wiring to it.
Check the wiring to the solenoid and to the governor including the kick-down switch. If operates fine out of O.D. check the governor. If the wiring to the governor terminals is damaged you cannot get into overdrive.
I assume you have a shop manual to aid you in getting the shifting straightened out.
Good luck to you, J.

 

[Vicegrips85]

Full stop!. You're saying that you can't shift into 3rd gear? There's no secondary requirements to hit 3rd gear. I sounds to me like your shift linkage got knocked out of alignment or bent during the engine r&r.
Figure this out first and the overdrive will probably follow. Go back to whoever worked on the car...

Harley,
Yep the shifter wont go into the third gear/OD position. With the car sitting in the shop the shifter will "lock" into 1,2, and R. But when shifted to the third gear position it only goes about half way, then when the clutch is released (the transmission never tries to catch) and the shifter springs from halfway to the third gear location, back to neutral. It does the same thi g whether the OD lever under the dash is in or out.

A little additional info: car has had 12v negative ground conversion years ago. The clutch is new and the flywheel had been proffessionally resurfaced (turned). The car runs and drives great in 1, 2, and R. Checked linkage... a little slop, but all clear of binding. I'm inclined its something simple like linkage, but cant pinpoint it. Thanks for any leads you can offer.

 

[Vicegrips85]

Are you saying the OD won’t kick in at 27mph while driving? Just removjng the motor from a OD transmission should not affect the OD performance mechanically. Im guessing something in the OD circuit did not get reconnected. The obvious and really the only OD electrical connection to the engine/ignition is the OD relay to coil wire. Make sure that circuit got reconnected correctly. Then check all the OD components in the engine bay for proper connections just in case something got unplugged during the engine removal.

Before doing anything major mechanically, checkout the circuits thoroughly. If it worked before the engine removal, it should continue to work now. My money is on wiring.

I'm studying the circuits in the manual and trying to translate them to be applicable to the 12V neg ground conversion the car had done years ago... perhaps you can answer a quick question about that specific circuit?

Does it only impact the cars ability to go into OD or would it keep the car from physically shifting into third as well?

 

[dmsfrr]

I'm studying the circuits in the manual and trying to translate them to be applicable to the 12V neg ground conversion the car had done years ago... perhaps you can answer a quick question about that specific circuit?

Does it only impact the cars ability to go into OD or would it keep the car from physically shifting into third as well?

,
Unless the transmission is damaged internally there isn't an OD part that should physically prevent shifting into 3rd gear.
Assuming you've ruled out a problem with the shifter itself, or external linkage that may have been damaged or 'rearranged' while the engine was removed & reinstalled.

 

[Mark R]

,
Unless the transmission is damaged internally there isn't an OD part that should physically prevent shifting into 3rd gear.
Assuming you've ruled out a problem with the shifter itself, or external linkage that may have been damaged or 'rearranged' while the engine was removed & reinstalled.

Ditto to dmsfrr’s reply. Barring any mechanical damage to the transmission, The car will shift normally through all three gears with the OD disconnected from the coil Or some other electrical component in the OD cicuit not working. It would appear from your questions that you are unable to physically shift into 3rd. If so you need to get that diagnosed and remedied before moving forward with the seprorate OD issue.

 

[74 Harley]

I'm leaning towards bent linkage. Look specifically straight up at the 3sp. Shift linkage coming down through the transmission tunnel. It only takes a small bend or mis alignment to interfere with shifting. Also make sure the bushing up there is intact. Engine r&r is not a pleasant job and the transmission components get beat up quite often. Your overdrive really has nothing to do with the issue of not going into 3rd gear.

 

[Vicegrips85]

I'm leaning towards bent linkage. Look specifically straight up at the 3sp. Shift linkage coming down through the transmission tunnel. It only takes a small bend or mis alignment to interfere with shifting. Also make sure the bushing up there is intact. Engine r&r is not a pleasant job and the transmission components get beat up quite often. Your overdrive really has nothing to do with the issue of not going into 3rd gear.

BINGO!
THANKS HARLEY! I knew it had to be something simple... heres what was wrong:
Linkage clearence at the shifter. During engine R&R the trans shifted slightly to the driver side (when inspecting the trans mount, the paint was wear indicated about a 1/4-1/8" off from pre-engine R&R). This move in location was just enough to cause one of the side plates that connects the shifter to the linkage to slap up against the VSS module housing. Attached are some pics of the misalignment if you ever hear of anyone encountering this again.

 

[74 Harley]

I have done far too many engine swaps in my life. Recently my 2007 F350 diesel. As experienced as I am I still managed to break the back up light switch. Cars really don't like being taken apart. I'm very happy you were able to get it fixed! Not as uncommon as you may think...