Shift lever locked from R
December 29th, 2021, 04:34 PM
#1
Registered User
Thread Starter
Join Date: Dec 2021
Posts: 6
Shift lever locked from R
Hi All,
Anyone happen to know if there is a vacuum modulator that prevents the hydromantic's shift lever from to going into reverse? Also if there is one any idea of it's location?
New to Oldsmobile's and Hydros. Forward gears all work fine, just the
lever and needle seems to be blocked from going into the R position.
Many Thanks in advance for any help.
Anyone happen to know if there is a vacuum modulator that prevents the hydromantic's shift lever from to going into reverse? Also if there is one any idea of it's location?
New to Oldsmobile's and Hydros. Forward gears all work fine, just the
lever and needle seems to be blocked from going into the R position.
Many Thanks in advance for any help.
December 29th, 2021, 06:12 PM
#2
Oldsdruid
Join Date: Dec 2007
Location: Southside Vajenya
Posts: 10,354
What year? You're pulling the selector lever all the way towards you, right?
Some have a hydraulic "reverse blocker piston" that extends out and physically prevents moving the shift linkage to reverse if the car's moving forward more than 5-10 mph. They will stick.
Car on lift, engine off, see if the blocker piston is extended. If it is try pushing it back in manually, then if it goes in have a helper start the car and move the trans selector lever thru all ranges with foot brake applied. The piston should stay retracted.
Then have your helper put the trans in D, release the brakes and watch the blocker piston. It should extend once the speedometer registers 10mph or so. Apply brakes till rear wheels stop and observe the piston. It should retract into the transmission case.
If not, it's varnished up in its bore or internal transmission hydraulic problem. It's also possible a high idle speed is fooling the transmission.
Some have a hydraulic "reverse blocker piston" that extends out and physically prevents moving the shift linkage to reverse if the car's moving forward more than 5-10 mph. They will stick.
Car on lift, engine off, see if the blocker piston is extended. If it is try pushing it back in manually, then if it goes in have a helper start the car and move the trans selector lever thru all ranges with foot brake applied. The piston should stay retracted.
Then have your helper put the trans in D, release the brakes and watch the blocker piston. It should extend once the speedometer registers 10mph or so. Apply brakes till rear wheels stop and observe the piston. It should retract into the transmission case.
If not, it's varnished up in its bore or internal transmission hydraulic problem. It's also possible a high idle speed is fooling the transmission.
Last edited by rocketraider; December 29th, 2021 at 06:28 PM.
December 30th, 2021, 11:41 AM
#3
Registered User
Thread Starter
Join Date: Dec 2021
Posts: 6
Thank you for the info.
Car is a 1956 88. Yes pulling up on the lever.
Will have to wait for the weather to clear up here, snow etc. Then can get serious.
Car is a 1956 88. Yes pulling up on the lever.
Will have to wait for the weather to clear up here, snow etc. Then can get serious.
What year? You're pulling the selector lever all the way towards you, right?
Some have a hydraulic "reverse blocker piston" that extends out and physically prevents moving the shift linkage to reverse if the car's moving forward more than 5-10 mph. They will stick.
Car on lift, engine off, see if the blocker piston is extended. If it is try pushing it back in manually, then if it goes in have a helper start the car and move the trans selector lever thru all ranges with foot brake applied. The piston should stay retracted.
Then have your helper put the trans in D, release the brakes and watch the blocker piston. It should extend once the speedometer registers 10mph or so. Apply brakes till rear wheels stop and observe the piston. It should retract into the transmission case.
If not, it's varnished up in its bore or internal transmission hydraulic problem. It's also possible a high idle speed is fooling the transmission.
Some have a hydraulic "reverse blocker piston" that extends out and physically prevents moving the shift linkage to reverse if the car's moving forward more than 5-10 mph. They will stick.
Car on lift, engine off, see if the blocker piston is extended. If it is try pushing it back in manually, then if it goes in have a helper start the car and move the trans selector lever thru all ranges with foot brake applied. The piston should stay retracted.
Then have your helper put the trans in D, release the brakes and watch the blocker piston. It should extend once the speedometer registers 10mph or so. Apply brakes till rear wheels stop and observe the piston. It should retract into the transmission case.
If not, it's varnished up in its bore or internal transmission hydraulic problem. It's also possible a high idle speed is fooling the transmission.
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