71 C10 350 rear main replacement - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Deano's 71 · 07-25-2016, 01:27 PM

I want (need) to replace the rear main seal. I was hoping to do it with the engine in the truck. I tried but discovered there isn't enough room between the oil pan and the cross member. I plan on unbolting the motor mounts, the transmission cross member and the shift linkage, then raising the motor up 2 to 3 inches to remove the pan. Does anyone know if this will work or maybe a better way?

geezer#99 · 07-25-2016, 03:04 PM

That'll sorta work.
Watch out for the distributor cap when you raise it. Might need to pop it off.
And watch the bottom rad hose.
You likely don't need to loosen the tranny mounts or the shift linkage. Depending on which tranny.
And you might need to rotate the motor to get the front crank throw up out of the way to slide the pan out.

Deano's 71 · 07-25-2016, 03:30 PM

I didn't even consider the twist in the crankshaft, thank you. I really appreciate your "cautions", I have look all around the motor and there looks to be ample room. The tranny is a TH-350, I figured I would loosen it just to be on the safe side, I tend to break things. Thanks again.

Deano's 71 · 07-31-2016, 12:52 PM

Geezer#99, thanks for your help. I forgot to check the fan, it had to be removed or it was going to remove the shroud. A question you might be able to help, how can I realign the motor mounts by myself? I tried for about two hours, and no luck. Other than that it worked great.

geezer#99 · 07-31-2016, 02:15 PM

Assuming you just removed the centre bolt from the bottom to seperate the mount, just grind a taper on the end of the bolt. So it looks like this bolt in the link.
http://www.chicagolandmgclub.com/techtips/mgb/101.html
Dress the threads and the bolt will thread right in.

garyd1961 · 07-31-2016, 02:36 PM

If it was me I would just go ahead and pull the motor. I've found that trying to take short cuts usually ends with the same amount of work and twice the frustration.

GASoline71 · 07-31-2016, 03:41 PM

This isn't a short cut. Many a rear main seal has been replaced with the engine in the vehicle. Not an "easy" job, but a doable job for the shade tree none the less.

Gary

Shady Rascal · 07-31-2016, 04:12 PM

Not a short cut at all. I can change one in the truck quicker than pulling the entire engine any time. Unbolt motor mounts and fan shroud, jack engine up and block motor mounts with wood. Drop torque converter dust cover, oil pan and oil pump and there you are.

A FelPro one piece pan gasket and FelPro Snap-Ups make it even easier.

07-25-2016, 01:27 PM	#1
Deano's 71 Registered User Join Date: May 2016 Location: San Tan Valley Posts: 5	71 C10 350 rear main replacement I want (need) to replace the rear main seal. I was hoping to do it with the engine in the truck. I tried but discovered there isn't enough room between the oil pan and the cross member. I plan on unbolting the motor mounts, the transmission cross member and the shift linkage, then raising the motor up 2 to 3 inches to remove the pan. Does anyone know if this will work or maybe a better way?

07-25-2016, 03:04 PM	#2
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,516	Re: 71 C10 350 rear main replacement That'll sorta work. Watch out for the distributor cap when you raise it. Might need to pop it off. And watch the bottom rad hose. You likely don't need to loosen the tranny mounts or the shift linkage. Depending on which tranny. And you might need to rotate the motor to get the front crank throw up out of the way to slide the pan out.

07-25-2016, 03:30 PM	#3
Deano's 71 Registered User Join Date: May 2016 Location: San Tan Valley Posts: 5	Re: 71 C10 350 rear main replacement I didn't even consider the twist in the crankshaft, thank you. I really appreciate your "cautions", I have look all around the motor and there looks to be ample room. The tranny is a TH-350, I figured I would loosen it just to be on the safe side, I tend to break things. Thanks again.

07-31-2016, 12:52 PM	#4
Deano's 71 Registered User Join Date: May 2016 Location: San Tan Valley Posts: 5	Re: 71 C10 350 rear main replacement Geezer#99, thanks for your help. I forgot to check the fan, it had to be removed or it was going to remove the shroud. A question you might be able to help, how can I realign the motor mounts by myself? I tried for about two hours, and no luck. Other than that it worked great.

07-31-2016, 02:15 PM	#5
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,516	Re: 71 C10 350 rear main replacement Assuming you just removed the centre bolt from the bottom to seperate the mount, just grind a taper on the end of the bolt. So it looks like this bolt in the link. http://www.chicagolandmgclub.com/techtips/mgb/101.html Dress the threads and the bolt will thread right in.

07-31-2016, 02:36 PM	#6
garyd1961 Registered User Join Date: May 2016 Location: Henderson NC Posts: 975	Re: 71 C10 350 rear main replacement If it was me I would just go ahead and pull the motor. I've found that trying to take short cuts usually ends with the same amount of work and twice the frustration.

07-31-2016, 04:12 PM	#8
Shady Rascal Registered User Join Date: Feb 2016 Location: Weatherford Texas Posts: 306	Re: 71 C10 350 rear main replacement Not a short cut at all. I can change one in the truck quicker than pulling the entire engine any time. Unbolt motor mounts and fan shroud, jack engine up and block motor mounts with wood. Drop torque converter dust cover, oil pan and oil pump and there you are. A FelPro one piece pan gasket and FelPro Snap-Ups make it even easier.



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