Trans help needed!
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Trans help needed!
Hi All,
I have a new to me '77 F250 with a 460 and a C6.
I have searched the forum for a problem like mine, but nothing seemed very similar so I'm hoping to get some advice.
My trans takes forever to shift when I first start driving. Fluid level is completely full, and it goes into gear and changes from reverse to drive very quickly like it should.
But, it will not shift into second until I wind the engine way up and hit about 35 mph. I'm not sure of the exact speed it shifts from second to third, but it it is late as well. As I drive along, the shift point happens sooner and sooner until it seems sort-of almost normal and shifts at about 25 (still feels late). Even at it's best it doesn't feel right, and the shifts are sometimes accompanied by a surge forward.
Your help is much appreciated in advance!
Russ
I have a new to me '77 F250 with a 460 and a C6.
I have searched the forum for a problem like mine, but nothing seemed very similar so I'm hoping to get some advice.
My trans takes forever to shift when I first start driving. Fluid level is completely full, and it goes into gear and changes from reverse to drive very quickly like it should.
But, it will not shift into second until I wind the engine way up and hit about 35 mph. I'm not sure of the exact speed it shifts from second to third, but it it is late as well. As I drive along, the shift point happens sooner and sooner until it seems sort-of almost normal and shifts at about 25 (still feels late). Even at it's best it doesn't feel right, and the shifts are sometimes accompanied by a surge forward.
Your help is much appreciated in advance!
Russ
Cargo Master
Joined: Nov 2009
Posts: 2,364
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From: starship enterprise
That is a tough one where it changes as the truck in warmed up. I would start at the modulator that is the little canister at the back of the tranny with the vaccuum line hooked to it. Make sure you are getting good manifold vaccuum to that line then from there once you have good vaccuum it might pay to check the modulator itself for a bad spring, bound up rod, or a ruptured diaphragm. Look here first, This is usually what causes that real late 1-2 shift also check your kickdown rod for free operation and adjustment. If these don't improve anything then there might be an internal governor issue or a sticky valve body. Good luck.
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
X2 on vacuum modulator. Check the vacuum line going to it, make sure there are no cracks or kinks in the line. Pull the hose off where it connects to the modulator, see if any tranny fluid leaks out of the modulator. If it does, replace the modulator.
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New User
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Thanks everyone.
It has been pouring down rain today, but I crawled under there earlier and pulled the 10,000 year old vacuum hose off of there. No fluid came out at all, but I think I might be wise to replace the old, and likely cracked hoses, and see what happens.
It has been pouring down rain today, but I crawled under there earlier and pulled the 10,000 year old vacuum hose off of there. No fluid came out at all, but I think I might be wise to replace the old, and likely cracked hoses, and see what happens.
Rusty Roller
Joined: Oct 2011
Posts: 1,423
Likes: 5
From: Santa Cruz Mountains
Also check the vacuum line at the back of the intake manifold. That hose that connects to the tube that supply's vac to the modulator can be cracked too. In other words there is a rubber hose at both ends.
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