Getting Started on my 71 GMCand I Need some advice... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

missinfishin10 · 06-15-2010, 08:11 PM

Hey I am finnally getting started on my project. A 71 GMC Long Fleetside.
Picture...
I purchased a complete truck with 88000 original miles. I bought it from #2 owner, although it was never registered to #2. #1 owner still lives in county. #2bought truck broken. Starter wouldn't engage flywheel all the time. #2 pulled engine and trans to replace flywheel and found flywheel ok but engine had excessive front to back play on crank. He stopped working on it. Engine and trans were both stored inside complete for the past 4-5 years. The engine appeantly has a Crank Thrust Issue. I havnt taken it apart yet. The #1 owner had TH350 rebuilt in 2004 by a local AMMCO (paperwork in glove box) its supposed to be excellent. I have read where the torque converter can balloon? or possibly the front pump could shove the TQ forward and cause simular damage.

This is a LOW BUDGET PROJECT... can a transmission guy look at the Tranny and TQ and determine the problem?

Zoomin · 06-15-2010, 08:46 PM

Do the number of teeth on the flywheel match up with the starter?

missinfishin10 · 06-15-2010, 09:21 PM

Yea Zoomin, its the right flywheel. Sometimes it was just to far out of place for the starter drive to engage it.

57larry · 06-15-2010, 09:23 PM

would a starter shim or 2 help?

raycow · 06-15-2010, 10:02 PM

If you have excessive crank end play, thats the crankshaft thrust bearing. Those almost never wear very much unless, as you suspect, you have a transmission problem.

The only thing is, the bearing would wear in the forward direction, not the rear. If I am understanding you correctly, you are saying the opposite - your flywheel has moved away from the starter, not toward it

You will need to pull it apart for a look.

Ray

beebster · 06-16-2010, 01:29 AM

I just went through this last week. My buddy bought a truck because the previous owner couldn't start it. It turned out the flywheel was on BACKWARDS!
We turned it around and bam! truck runs perfect.
yes, you can put a flywheel on backwards we found out LOL.

71meangreenc10 · 06-16-2010, 08:13 AM

Quote:

Originally Posted by beebster

Yes you can put a flywheel on backwards we found out LOL.

Murphys Law is a motha.......

Smitty

06-15-2010, 09:21 PM	#3
missinfishin10 Amazed Member Join Date: May 2010 Location: Dahlonega Georgia Posts: 486	Re: Getting Started on my 71 GMCand I Need some advice... Yea Zoomin, its the right flywheel. Sometimes it was just to far out of place for the starter drive to engage it.

06-15-2010, 09:23 PM	#4
57larry Registered User Join Date: Nov 2007 Location: Indianapolis Posts: 1,162	Re: Getting Started on my 71 GMCand I Need some advice... would a starter shim or 2 help?

06-15-2010, 10:02 PM	#5
raycow Registered User Join Date: Mar 2003 Location: San Francisco, CA USA Posts: 2,454	Re: Getting Started on my 71 GMCand I Need some advice... If you have excessive crank end play, thats the crankshaft thrust bearing. Those almost never wear very much unless, as you suspect, you have a transmission problem. The only thing is, the bearing would wear in the forward direction, not the rear. If I am understanding you correctly, you are saying the opposite - your flywheel has moved away from the starter, not toward it You will need to pull it apart for a look. Ray

06-16-2010, 01:29 AM	#6
beebster Registered User Join Date: Jan 2009 Location: Aurora,Il ..born,raised and still live in the same house Posts: 286	Re: Getting Started on my 71 GMCand I Need some advice... I just went through this last week. My buddy bought a truck because the previous owner couldn't start it. It turned out the flywheel was on BACKWARDS! We turned it around and bam! truck runs perfect. yes, you can put a flywheel on backwards we found out LOL. __________________ I love stock! Not really into the whole bagged, squished,chopped, drooped,cut, bent,lifted,twisted,split,decked,massaged,tubbed,jacked trend. (o.k. slightly lowered is fine) For the love of god, just drive it before you forget what the truck is supposed to look like !....LOL

06-15-2010, 08:11 PM	#1
missinfishin10 Amazed Member Join Date: May 2010 Location: Dahlonega Georgia Posts: 486	Getting Started on my 71 GMCand I Need some advice... Hey I am finnally getting started on my project. A 71 GMC Long Fleetside. Picture... I purchased a complete truck with 88000 original miles. I bought it from #2 owner, although it was never registered to #2. #1 owner still lives in county. #2bought truck broken. Starter wouldn't engage flywheel all the time. #2 pulled engine and trans to replace flywheel and found flywheel ok but engine had excessive front to back play on crank. He stopped working on it. Engine and trans were both stored inside complete for the past 4-5 years. The engine appeantly has a Crank Thrust Issue. I havnt taken it apart yet. The #1 owner had TH350 rebuilt in 2004 by a local AMMCO (paperwork in glove box) its supposed to be excellent. I have read where the torque converter can balloon? or possibly the front pump could shove the TQ forward and cause simular damage. This is a LOW BUDGET PROJECT... can a transmission guy look at the Tranny and TQ and determine the problem? Attached Images

06-15-2010, 08:46 PM	#2
Zoomin Man of Mini-Talents Join Date: Sep 2009 Location: Oklahoma City, OK Posts: 4,295	Re: Getting Started on my 71 GMCand I Need some advice... Do the number of teeth on the flywheel match up with the starter?



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