1957 automatic reverse clunking

[mayman]

Have an issue with my 56 T-bird on when I reverse it it has a clunking sound I don't if I put my brake on hard I bypasses that is there adjustment on that I have checked all my U-joints Transmissions good transmission mounts good we built the whole thing no leaks just can't figure that out when I get ready to put it in reverse or drive it clunks a little bit I don't put the brake down please advise

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[Tom Alpers]

Have an issue with my 56 T-bird on when I reverse it it has a clunking sound I don't if I put my brake on hard I bypasses that is there adjustment on that I have checked all my U-joints Transmissions good transmission mounts good we built the whole thing no leaks just can't figure that out when I get ready to put it in reverse or drive it clunks a little bit I don't put the brake down please advise

What you are describing sounds more or less normal to me. These transmissions don't have as many pressure controls as newer ones do and sometimes will bang into gear.

 

[bmac1060]

Make sure the engine idle (after warm up) is correct, approximately 600rpm (in neutral).
To high and it will clunk/bang. And as Tom said, some degree of bang/clunk is normal.

 

[Old school gear head]

Could be the pinion backlash. Make sure the trans shift rod is perfectly adjusted along with the proper idle speed!

 

[Bruce Hardy]

Also isn't there a reverse band adjustment.And I could be wrong on that also.

 

[Old school gear head]

Good point about that reverse band, but I’m not sure I do know there’s an adjustment for the forward band but has to be carefully adjusted and torqued in inch pounds!! I know because I almost adjusted it in foot pounds and could have broken the aluminum fork!!! The manual I was following didn’t specify inch or foot it just said tighten to 25 if my memory serves me correctly!!

 

[doug7740]

Since your concern is a hard engagement when shifting from neutral to drive or neutral to reverse, make sure your idle speed is not set too high. Your engine should be idling at 600 RPM when shifting into reverse or drive.

If the band is adjusted too tight that might cause a hard engagement when shifting into gear, but you need to know which band to adjust. Let's look at a band/clutch application chart for the answer.



The only band that is applied in low, drive or reverse is the rear band. The rear band is the only band that you'll need to adjust.

Here are the band adjustment points for both the rear and front bands.



REAR BAND ADJUSTMENT:

1. Loosen the lock nut and tighten the adjusting screw to 10-foot pounds.
2. Back of the adjusting screw 1 ½ turns and tighten the lock nut to a torque of 35–40 foot pounds.

FRONT BAND ADJUSTMENT:

1. With the transmission oil pan removed, back off the adjusting screw lock nut and adjusting screw far enough to insert a ¼” wide metal block in between the servo piston rod and the adjusting screw.
2. Turn the screw until it contacts the metal block, then tighten screw to about 10-inch pounds and back off one turn.
3. While holding the adjustment screw in position, tighten the lock nut down to 20–25 foot pounds.

doug7740
1955 Thunderbird Blue