No 1st Gear Big Block 727 Transmission

[ykf7b0]

Help,
I am experiencing a problem with my big block 727 trans. I cannot get first gear to engage at all. I have disconnected the shifter cable, ( Hurst Quarter Stick), and manually moved the shift arm all the way forward and I'm still only able to get 2nd gear. 2nd to 3rd gears are ok as is reverse, park and neutral. Any idea's and suggestions are appreciated! Thanks! Greg

 

[racedodge]

drop the pan and check the rear servo seals to ensure they are not damaged. reverse runs off of a higher pressure, so reverse could be still putting enough pressure on the piston to engage the band. 1st runs off of less pressure so the servo piston may not be building up enough pressure to engage the rear band. would be a good time to check and see if your rear band is properly adjusted before you remove the servo. if its a band adjustment.. its an easy fix of tightening to 72" lbs, then backing off two turns and then securing the adjuster nut to the appropriate torque (which slips me right now).

 

[ykf7b0]

Thanks very much for that info!!!! Greg

 

[racedodge]

30 ft/lbs is the reverse band locking adjuster nut's torque, and its a 11/16" socket. you will need a 5/16" wrench to adjust the adjuster screw.

 

[Obnoxus]

Running my coronet hard last night in the quarter 100 mph 2 3rds the the way bang dust and dirt in car fluid on the road and a broken u joint on front of shaft is my tranny toast?

 

[racedodge]

Running my coronet hard last night in the quarter 100 mph 2 3rds the the way bang dust and dirt in car fluid on the road and a broken u joint on front of shaft is my tranny toast?

could be, could not be... visibly inspect your tailshaft housing for cracks. in many cases a front u-joint failure will cause the rear sprag to have too much stress on it, and then cause it to fail.. but there are rare cases where it will remain intact.

for insurance reasons, i would drop it and inspect it (if you can do this) or take it to a reputable trans shop for a lookey loo.

 

[SUPERSTOCKRACER]

drop the pan and check the rear servo seals to ensure they are not damaged. reverse runs off of a higher pressure, so reverse could be still putting enough pressure on the piston to engage the band. 1st runs off of less pressure so the servo piston may not be building up enough pressure to engage the rear band. would be a good time to check and see if your rear band is properly adjusted before you remove the servo. if its a band adjustment.. its an easy fix of tightening to 72" lbs, then backing off two turns and then securing the adjuster nut to the appropriate torque (which slips me right now).

it's not the rear servo. if it was the rear servo seal, you wouldn't have reverse but all forward gears. I'm betting the clutches or band. ask me how i know?

 

[racedodge]

1st is engaged by the rear clutch, the rear servo (55psi, which means the rear band is applied). reverse is engaged by the front clutch and the rear servo (230-260psi, which means the rear band is applied). there is a huge difference in pressure on the rear servo.. if there is a light leak in the seal or the band is not adjusted properly, 1st gear may not work and it will slip BUT reverse may still engage due to the 4-5x higher pressure being applied to the rear band. reverse may not be 100% engaged due to the band adjustment or bad seal, but it could still be effective enough to put it in gear, whereas first would not be applied at all. the reverse band MUST be applied in order to have first and reverse gear.

not saying you are wrong superstockracer, just saying that your problem (from the pics) shows a bad rear servo snap ring or broken rear band (which is extremely rare in and of itself). just a question, but did the rear servo lever strut get installed sideways or longwise? if it was put in sideways, it would cause entirely too much movement of the rear servo lever causing the servo piston to top out and the strut to fall away leading to rear snap ring failure and the ballooning of your spring retainer.

 

[ingear12]

Not for nothin', but I'd bet on the low roller clutch being damaged.