Reverse Issue

[Sixty_vette]

Well, finally got some time and descent weather to take the 1960 Vette for a spin. She ran like a champ and boy did I get the looks (well the car did - not me - LOL)

Anyways, to make a long story short, due to the garage setup and no power steering I found that if I back up the driveway, I can pull into the garage with relative ease (rather than driving up normally and doing a 3 point turn without power steering).

When I back out of the garage, not fully releasing the clutch everything is fine, but when I was backing up the driveway, I had some severe chatter - almost to the point I would describe it as a violent shaking of the car. So I am reluctant to call it clutch chatter as it does not do it in 1st or 2nd gear from a dead stop.

I know it is rather difficult to diagnose problems over the internet - just curious if anyone ran into this or has any clue where to begin looking.

Thanks in advance from the newbie Vette owner!

 

[Hib Halverson]

This was backing the car uphill while slipping the clutch?

 

[Sixty_vette]

This was backing the car uphill while slipping the clutch?

Well not really - I was in our cul-de-sac on level ground backing up towards my drive. Seems when I fully released the clutch while in reverse was when it happened, so I dont believe it was an uphill issue. Seems more like a full clutch release more so than a hill issue. As long as I "ride the clutch" - it is smooth.

Hope this helps!

 

[vigman]

My guess

Motor mounts and or tranny tail shaft mount......

Mike

 

[Sixty_vette]

Motor mounts and or tranny tail shaft mount......

Mike

Thanks Mike - will check those out - got me puzzled - LOL!

 

[BigJimZ16]

Motor mounts and or tranny tail shaft mount......

Mike

Motor mount, right side... I was at Chevrolet in the '70s, I probably changed 250 sets of motor mounts and installed restraints on another 100...

 

[Sixty_vette]

Motor mount, right side... I was at Chevrolet in the '70s, I probably changed 250 sets of motor mounts and installed restraints on another 100...

Thanks, but whats got me confused is why ONLY in reverse - why not in 1st gear also? :ugh

 

[Tom Bryant]

You guys know that a '60 doesn't have block side mounts like a normal car, don't you? It uses a saddle that mounts between the water pump and the block. If the cushion is there along with the bolt it isn't going anywhere.

 

[Hib Halverson]

Motor mount, right side... I was at Chevrolet in the '70s, I probably changed 250 sets of motor mounts and installed restraints on another 100...

53-62 uses a completely different type of engine mounting system than the ones you replaced when working for Chevrolet. It was like the 55-57 Chevy...four point...two on the clutch housing and two at the front of the engine.

 

[BigJimZ16]

You guys know that a '60 doesn't have block side mounts like a normal car, don't you? It uses a saddle that mounts between the water pump and the block. If the cushion is there along with the bolt it isn't going anywhere.

Duh, yah I know the difference... but when the OP mentioned the problem in reverse, the old memory kicked into "similar symptom mode". Thanks for bringing me back to the now...

 

[BigJimZ16]

53-62 uses a completely different type of engine mounting system than the ones you replaced when working for Chevrolet. It was like the 55-57 Chevy...four point...two on the clutch housing and two at the front of the engine.

Thanks for reminding me Hib, yah I knew that... DUH!

 

[BigJimZ16]

Thanks, but whats got me confused is why ONLY in reverse - why not in 1st gear also? :ugh

Sorry for the bad info, I was thinking everything other than Vettes... The reason why only in reverse is still the same though. The torque of the engine as transmitted through the drive shaft is in the opposite direction when you are in reverse.
Forward direction the vehicle tries to rotate the engine assy counter clockwise (facing the front of the engine) where as in reverse the engine tries to rotate clockwise lifting the right side of the engine in relation to the frame. It's this relative motion that can put things like clutch linkage into a bind.

 

[Tom Bryant]

Even though the mount can't separate you may still have a loose or missing bolt allowing the engine to twist so the info wasn't all bad. Basically the same effect from a slightly different cause. Check your front mount bolts and the condition of the rubber cushions. There is a torque spec for these bolts too.

The transmission has a mount on the tail housing that sits on the X member of the frame. It is not like the bell housing mounts of a '55-'57 passenger car. Unlike modern mounts the rubber cushion is a separate piece. You may have a missing bolt here or the cushion is deteriorated. I looked under mine to make sure I remembered it correctly but didn't take my camera with me. See page 47 of the Paragon catalog.

Tom

 

[Hib Halverson]

Even though the mount can't separate you may still have a loose or missing bolt allowing the engine to twist so the info wasn't all bad. Basically the same effect from a slightly different cause. Check your front mount bolts and the condition of the rubber cushions. There is a torque spec for these bolts too.

The transmission has a mount on the tail housing that sits on the X member of the frame. It is not like the bell housing mounts of a '55-'57 passenger car. Unlike modern mounts the rubber cushion is a separate piece. You may have a missing bolt here or the cushion is deteriorated. I looked under mine to make sure I remembered it correctly but didn't take my camera with me. See page 47 of the Paragon catalog.

Tom

I agree with Tom.
My earlier comment about the mount system was only to differentiate between the 53-62 "four-point" engine mount and the 63-82 "three point" system.

The very early mounts can still have problems which might cause that shuddering.

 

[vigman]

Learn something new everyday

Ok I think the effect is still the same ... or more correctly, the transmission output torque is reversed when in reverse...

Easy way to test, chock the rear wheels ( both sides, foward AND back of the tire on level ground ) keep hood open. ...
Try taking off EASY by slipping the clutch ( careful not to smoke or glaze the clutch ).

In first, you will see the air cleaner shift and the engine will rise a bit... now try in reverse... same, more motion ?

If you have way more engine position motion in reverse...it's affecting the how the clutch linkage between the pedal and the clutch throw out arm is working...

The engine to frame mount is not 100% rigid so there SHOULD be a little give... but not alot..
If the mount is rotted, broken, crushed or malformed due to age...
Bolts not up to torque, wrong length bolt, missing bolt... etc etc Bingo

Front mount
http://www.ebay.com/itm/1961-1962-C...Parts_Accessories&hash=item45fe8931ae&vxp=mtr

Front rubbers
http://www.ebay.com/itm/53-62-Corve...61|Model:Corvette&hash=item19cbe77a4d&vxp=mtr

Rear mount
http://www.ebay.com/itm/1953-1954-1...Parts_Accessories&hash=item5d3ee1999e&vxp=mtr

Rear rubber
http://www.ebay.com/itm/C1-Corvette...61|Model:Corvette&hash=item51a2e84ff9&vxp=mtr



Mike