Tranny Help Please!!!! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

orange72350 · 09-03-2003, 11:32 PM

I have a 72 gmc with a 350 and an auto tranny, a turbo 350 i think, and its been giving me grief. The lever that comes off of the drivers side of the tranny that rocks back and forth to shift gears keeps jumping off. The lever that connects the shift linkage to tranny seems to want to keep jumping off. this might sound confusing, but the bottom prong that the shift linkage connects to, which has a spring that seems to retain the linkage on the shaft, seems to be jumping. it only does it when i really drop the hammer and the rearend gets traction.I dont know if anyone has any clue what im talking about, but i really dont know what gives.I reconnected the linkage, and worked it back and forth for while, and wathced it. i took it for a spin, and the moment i really gave it to her, bang, it was off agin.Is one prong on the shift rocker supposed to be shorter than the other? my top one is shorter, while the bottom one is longer. Is this right? im really sorry bout the long post, but its really important. this thing is my only transport right now, so till i get it fixed its the good old footmobile. thanx alot guys. sorry if im confusin
thanx in advance
dale

Tx Firefighter · 09-03-2003, 11:52 PM

Oh, that's an easy one!

You've got a broken left motor mount. The engine is rocking up on the left side when it torques up. It'll cost you about $10 to replace.

orange72350 · 09-04-2003, 12:02 AM

Oh. a motor mount. I just replaced em all. maybe the were the wrong ones, or maybe the bolts arent torqued engough. ill check em tommrow.when u say left u mean drivers side? That does make sense. ill figure it out tommorow. Thanx man
dale

mrein3 · 09-04-2003, 07:27 AM

Open the hood. Climb in the drivers seat. Make sure nobody or nothing is in front of you or behind you for safety. Start the engine. One foot on the brake, brakes fully applied, shift into reverse. With your left foot still holding the brakes, rev the engine while looking at the air cleaner. Do the same in drive. If the engine jumps up one way and not the other, you have to replace (or maybe retorque in your case) that side's motor mount.

Tx Firefighter · 09-04-2003, 08:09 AM

If the mounts are new, you probably have too long of bolt, or the big thick washer is missing. Sounds like it's bottoming out before cinching down.

orange72350 · 09-04-2003, 10:17 AM

KEwl guys./ Thanx for the help. I got her figured now. im gonna go try and fix it in about an hour.thanx again
dale

Tx Firefighter · 09-04-2003, 10:23 PM

Sounds like you got lucky. When the engine torques over enough to pop the linkage out of place, it usually breaks the fan shroud too. Makes a real embarrasing noise when that happens.

orange72350 · 09-05-2003, 12:00 AM

Hehe. i got lucky. took the fan shroud out day before yesterday to paint it. heard the temp was gonna come down a bit, so it seemed like a good time to paint it. What size bolts do the engine mounts take? it seems to me that they were both a 3/8 bolt, but i cant seem to remember. gonna throw new bolts in both sides to freshen it up. btw, u were right. left side of the engine came loose, but i never checked the bolt size.trhanx fer tha help
dale

Tx Firefighter · 09-05-2003, 12:03 AM

You're welcome

That's what this board is for, helping others.

JimKshortstep4x4 · 09-05-2003, 08:15 AM

Orange,

The bolts for the mount to the engine are 3/8-16 but they have a none standard length as they were 3/4" long from the factory. 1" bolts will bottom out unless you cut some off or add extra washers.

Jim

Longhorn Man · 09-06-2003, 11:45 PM

You are kinda lucky that you have a 72 with the cable actuated throtle. The 70 and older has the throttle rod, and when the motor mounts come loose, there is a chance of the throttle binding and staying in the open position...even accelirating too.
Enough to make you soil your pants.

09-03-2003, 11:32 PM	#1
orange72350 Registered User Join Date: Jan 2003 Location: Cold, Snowy High Level, Alberta Canada Eh Posts: 394	Tranny Help Please!!!! I have a 72 gmc with a 350 and an auto tranny, a turbo 350 i think, and its been giving me grief. The lever that comes off of the drivers side of the tranny that rocks back and forth to shift gears keeps jumping off. The lever that connects the shift linkage to tranny seems to want to keep jumping off. this might sound confusing, but the bottom prong that the shift linkage connects to, which has a spring that seems to retain the linkage on the shaft, seems to be jumping. it only does it when i really drop the hammer and the rearend gets traction.I dont know if anyone has any clue what im talking about, but i really dont know what gives.I reconnected the linkage, and worked it back and forth for while, and wathced it. i took it for a spin, and the moment i really gave it to her, bang, it was off agin.Is one prong on the shift rocker supposed to be shorter than the other? my top one is shorter, while the bottom one is longer. Is this right? im really sorry bout the long post, but its really important. this thing is my only transport right now, so till i get it fixed its the good old footmobile. thanx alot guys. sorry if im confusin thanx in advance dale __________________ 2003 yamaha raptor. Stock, but it still hauls!!!! 2000 skiddo mxz 700. Camoplast 1.5 inch track, jaws twin pipes, b+b can, custom built and weighted clutch, wiseco piston, high comp heads. its very fast. wow. 72 c-10 longbox. Bright Orange. Brand new 350, rv cam, performer intake, qjet, headers, 2 1/2 inch exhaust into hooker areo chamber mufflers. Body work coming soon. "dont let yer mind wander, its to little to go places by itself." "Forget the herse, cause i'll never die"-ACDC Back In Black "If It's To Loud, Yer Just Too Old" "I Love Anything Fast Enough To Do Something Stupid In" "Instant idiot, just add beer!!""

09-03-2003, 11:52 PM	#2
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Oh, that's an easy one! You've got a broken left motor mount. The engine is rocking up on the left side when it torques up. It'll cost you about $10 to replace. __________________ I'm on the Instagram- @Gearhead_Kevin

09-04-2003, 12:02 AM	#3
orange72350 Registered User Join Date: Jan 2003 Location: Cold, Snowy High Level, Alberta Canada Eh Posts: 394	Oh. a motor mount. I just replaced em all. maybe the were the wrong ones, or maybe the bolts arent torqued engough. ill check em tommrow.when u say left u mean drivers side? That does make sense. ill figure it out tommorow. Thanx man dale __________________ 2003 yamaha raptor. Stock, but it still hauls!!!! 2000 skiddo mxz 700. Camoplast 1.5 inch track, jaws twin pipes, b+b can, custom built and weighted clutch, wiseco piston, high comp heads. its very fast. wow. 72 c-10 longbox. Bright Orange. Brand new 350, rv cam, performer intake, qjet, headers, 2 1/2 inch exhaust into hooker areo chamber mufflers. Body work coming soon. "dont let yer mind wander, its to little to go places by itself." "Forget the herse, cause i'll never die"-ACDC Back In Black "If It's To Loud, Yer Just Too Old" "I Love Anything Fast Enough To Do Something Stupid In" "Instant idiot, just add beer!!""

09-04-2003, 07:27 AM	#4
mrein3 Registered User Join Date: Feb 2000 Location: Center City, MN, USA Posts: 3,253	Open the hood. Climb in the drivers seat. Make sure nobody or nothing is in front of you or behind you for safety. Start the engine. One foot on the brake, brakes fully applied, shift into reverse. With your left foot still holding the brakes, rev the engine while looking at the air cleaner. Do the same in drive. If the engine jumps up one way and not the other, you have to replace (or maybe retorque in your case) that side's motor mount. __________________ '70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN

09-04-2003, 08:09 AM	#5
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	If the mounts are new, you probably have too long of bolt, or the big thick washer is missing. Sounds like it's bottoming out before cinching down. __________________ I'm on the Instagram- @Gearhead_Kevin

09-04-2003, 10:17 AM	#6
orange72350 Registered User Join Date: Jan 2003 Location: Cold, Snowy High Level, Alberta Canada Eh Posts: 394	KEwl guys./ Thanx for the help. I got her figured now. im gonna go try and fix it in about an hour.thanx again dale __________________ 2003 yamaha raptor. Stock, but it still hauls!!!! 2000 skiddo mxz 700. Camoplast 1.5 inch track, jaws twin pipes, b+b can, custom built and weighted clutch, wiseco piston, high comp heads. its very fast. wow. 72 c-10 longbox. Bright Orange. Brand new 350, rv cam, performer intake, qjet, headers, 2 1/2 inch exhaust into hooker areo chamber mufflers. Body work coming soon. "dont let yer mind wander, its to little to go places by itself." "Forget the herse, cause i'll never die"-ACDC Back In Black "If It's To Loud, Yer Just Too Old" "I Love Anything Fast Enough To Do Something Stupid In" "Instant idiot, just add beer!!""

09-04-2003, 10:23 PM	#7
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Sounds like you got lucky. When the engine torques over enough to pop the linkage out of place, it usually breaks the fan shroud too. Makes a real embarrasing noise when that happens. __________________ I'm on the Instagram- @Gearhead_Kevin

09-05-2003, 12:00 AM	#8
orange72350 Registered User Join Date: Jan 2003 Location: Cold, Snowy High Level, Alberta Canada Eh Posts: 394	Hehe. i got lucky. took the fan shroud out day before yesterday to paint it. heard the temp was gonna come down a bit, so it seemed like a good time to paint it. What size bolts do the engine mounts take? it seems to me that they were both a 3/8 bolt, but i cant seem to remember. gonna throw new bolts in both sides to freshen it up. btw, u were right. left side of the engine came loose, but i never checked the bolt size.trhanx fer tha help dale __________________ 2003 yamaha raptor. Stock, but it still hauls!!!! 2000 skiddo mxz 700. Camoplast 1.5 inch track, jaws twin pipes, b+b can, custom built and weighted clutch, wiseco piston, high comp heads. its very fast. wow. 72 c-10 longbox. Bright Orange. Brand new 350, rv cam, performer intake, qjet, headers, 2 1/2 inch exhaust into hooker areo chamber mufflers. Body work coming soon. "dont let yer mind wander, its to little to go places by itself." "Forget the herse, cause i'll never die"-ACDC Back In Black "If It's To Loud, Yer Just Too Old" "I Love Anything Fast Enough To Do Something Stupid In" "Instant idiot, just add beer!!""

09-05-2003, 12:03 AM	#9
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	You're welcome That's what this board is for, helping others. __________________ I'm on the Instagram- @Gearhead_Kevin

09-05-2003, 08:15 AM	#10
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Orange, The bolts for the mount to the engine are 3/8-16 but they have a none standard length as they were 3/4" long from the factory. 1" bolts will bottom out unless you cut some off or add extra washers. Jim

09-06-2003, 11:45 PM	#11
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	You are kinda lucky that you have a 72 with the cable actuated throtle. The 70 and older has the throttle rod, and when the motor mounts come loose, there is a chance of the throttle binding and staying in the open position...even accelirating too. Enough to make you soil your pants.

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