I'm confused???
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New User
Joined: Jan 2009
Posts: 9
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I'm confused???
I have a 1988 ford 350 with 7.3 non turbo with auto trans
When I hit the gas it takes off smooth but it will not shift in second gear until I let off of the gas but when my foot stays on the gas pedal it stays in first could someone let me know why this is happening I'm confused and dont know where to start
When I hit the gas it takes off smooth but it will not shift in second gear until I let off of the gas but when my foot stays on the gas pedal it stays in first could someone let me know why this is happening I'm confused and dont know where to start
Postmaster
Joined: Jun 2007
Posts: 2,621
Likes: 1
From: Sweetwater Texas
Its a C6 tranny correct? Most likely a combo of a slightly clogging filter, and a I forgot the name of it, but there is a valve that is on the side of the tranny that can wear out. Mine does the same thing when its cold outside, but when it warms up, it shifts just fine.
Senior User
Joined: Aug 2008
Posts: 123
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From: FL's Ghettos/Trailer Prk
Mine did the same thing. Check the vaccum modulator on the passenger side of the tranny. It will have a vaccum line to it. Pull the line if you see fluid replace it. only like a 15.00 part.
When it does shift if it shifts hard and in the higher rpm rang it could be that your Vaccum Regulator Valve (VRV) needs to be adjusted. It's located on the driver's side of your IP has vaccum lines running to it. Search the forum for VRV test. Hope this helps.
When it does shift if it shifts hard and in the higher rpm rang it could be that your Vaccum Regulator Valve (VRV) needs to be adjusted. It's located on the driver's side of your IP has vaccum lines running to it. Search the forum for VRV test. Hope this helps.
Post Fiend
Joined: Jan 2005
Posts: 8,402
Likes: 10
Mine did the same thing. Check the vaccum modulator on the passenger side of the tranny. It will have a vaccum line to it. Pull the line if you see fluid replace it. only like a 15.00 part.
When it does shift if it shifts hard and in the higher rpm rang it could be that your Vaccum Regulator Valve (VRV) needs to be adjusted. It's located on the driver's side of your IP has vaccum lines running to it. Search the forum for VRV test. Hope this helps.
When it does shift if it shifts hard and in the higher rpm rang it could be that your Vaccum Regulator Valve (VRV) needs to be adjusted. It's located on the driver's side of your IP has vaccum lines running to it. Search the forum for VRV test. Hope this helps.
The filter Dean was refering to is the transmission fluid filter.
All this assumes you have a 3 speed C6 trans with no overdrive.
Postmaster
Joined: Jun 2007
Posts: 2,621
Likes: 1
From: Sweetwater Texas
I wasn't referring to that filter, I was referring to dropping the tranny pan and changing the filter (its more like a fine screen). When I got my 88 it was acting wierd in its shifting and after changing my filter it cured most of its problems.
i ain't rite
Joined: Mar 2005
Posts: 65,579
Likes: 5,611
From: Marlboro Mental Hospital.
you are not getting proper vacuum to the modulator valve in the trans. first thing i would do is check the vacuum pump. it sounds like your pump is dying. you need at least 17 inches of vacuum for the trans to work properly.
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Lead Driver
Joined: Nov 2003
Posts: 6,900
Likes: 3
From: Campbell River, B.C.
Check the vacuum related parts mentioned so far. You should also check the VRV right on the side of the injector pump to see if anything is broken. The VRV (vaccum regulator valve) is basically a throttle position sensor for the C6 transmission. It modulates vacuum to control line pressure and shift scheduling. Low vacuum will result in high line pressure and late shifting, while high vacuum will cause early, soft shifting.
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