F800 idle speed

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Dec 8, 2013 | 01:35 PM

mjlayton

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4wd Low

Joined: Feb 2010

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F800 idle speed

I have a 92 F800, 7.8L, Allison MT643. Since it was serviced last the idle speed is around 900 rpm. Shop says that's where it shoud be, but truck nearly jumps out from under you when you put it in gear. Does anyone know what the idle speed should be?
Thanks,
Mike

Dec 9, 2013 | 10:28 PM

Pete Kildow

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Joined: Jun 2013

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Will look at my book tomorrow. I know my Manual trans 7.8 idles around 600 RPMs.

Dec 10, 2013 | 08:30 AM

mjlayton

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4wd Low

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Thanks, that sounds like a more reasonable speed to me.

Dec 16, 2013 | 04:58 AM

Pete Kildow

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Quote:

Originally Posted by mjlayton

Thanks, that sounds like a more reasonable speed to me.

If I'm seeing it right its showing 750 at Idle. Sorry for the delay, but my stinking back took me out. So have not even been able to get around.

Pete

Dec 16, 2013 | 07:14 AM

mjlayton

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4wd Low

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Thanks!!!

Hope your back pain gets better.

Mike Layton

Dec 16, 2013 | 07:57 PM

nevrenufhp

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Joined: Feb 2003

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From: Sacramento

650-750rpm in gear

Dec 16, 2013 | 08:23 PM

mjlayton

Thread Starter

4wd Low

Joined: Feb 2010

Posts: 14

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Thanks!!

Had an '84 F150 Custom, short bed, 300 Tri-Y headers and a Paxton blower. Had to install an engine oil cooler or it would foam the oil in a drag race.

Mike