Transmission Problems after engine work

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Oct 18, 2017 | 07:23 AM

Andrewfriend

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Transmission Problems after engine work

Hi, I’ve just picked up my 72 Auto transmission F100 from the shop. It had a new exhaust manifold fitted as well as a new intake manifold gasket. Now driving it home is barely changes gear only after revving for about 3-4 minutes. It then finally drops into gear very heavily. I have had no problems with the transmission before and it was working perfect when I drove it to the shop. Any ideas what could have gone wrong? Thanks very much.

Oct 18, 2017 | 07:28 AM

Mark Kovalsky

Frmr Ford Trans Engr

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From: SE Florida

It's likely that the vacuum line from the intake manifold to the transmission was not connected.

Oct 18, 2017 | 07:53 AM

Andrewfriend

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Thanks for the advice Mark. Are there any pics or videos around that show what I need to check to see if this is the case? Thanks again!!!

Oct 18, 2017 | 09:32 AM

Mark Kovalsky

Frmr Ford Trans Engr

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From: SE Florida

I don't have one. A search on YouTube or Google will probably find one.

The vacuum hose goes to the intake manifold and the vacuum modulator on the rear of the transmission.

Jan 10, 2018 | 05:50 AM

Andrewfriend

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Quote:

Originally Posted by Mark Kovalsky

I don't have one. A search on YouTube or Google will probably find one.

The vacuum hose goes to the intake manifold and the vacuum modulator on the rear of the transmission.

Hi, I know it’s been a while but I never did get the problem fixed. I checked the vacuum hoses and nothing obvious there, I also replaced the vacuum modulator. The gear changes are still really bad. The engine cries out to change gear for about a minute and finally the gear drops into place. Any other thoughts. Before the intake was removed it changed gear sweetly. Thanks!!!!!

Jan 10, 2018 | 06:50 AM

Mark Kovalsky

Frmr Ford Trans Engr

Joined: Aug 1999

Posts: 24,730

Likes: 2,658

From: SE Florida

You have a problem getting vacuum to the vacuum modulator. Fix that and the trans will shift fine again. How much vacuum does the modulator see at engine idle?