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Re: 1978 F-100 tranny problem
On 25 Jan 2006 20:30:43 -0800, "snuffy"
<jgrant1978@yahoo.com> wrote:
>Just had this transmission rebuilt by someone who does an excellent job
>on GM transmissions, but obviously not so good with a Ford
>transmission. It is a C-6, behind a 300 cubic inch six. It shifts great
>on the 1-2 shift, but lags horribly on the 2-3 shift, like it is
>slipping. All the guy that rebuilt it can do is scratch his head and
>say "I dunno...something ain't right." Any clues as to why this shift
>is so screwy? Band adjustment? Modulator valve out of adjustment?
In the C6, the modulator controls the 1-2 shift based on
engine load. Modulator is not a problem if 1-2 shift is
good. Second band is externally adjustable but, not likely
problem since 1-2 shift is OK. 2-3 shift is controlled by
governor in tailshaft housing. First thing I would check is
whether it is sticking. This can be done by removing the
rear mount and tail shaft housing. If the shift is good
when it does shift, I would go for the governor. There may
also be a problem with the valve body, but, that can be
pulled and double checked for correct gaskets and ball
placement by pulling the pan. He should have an ATSG manual
with it's diagrams handy when he does this. there are a
couple of different gaskets for the valve body. The wrong
gaskets can do this as well as incorrect torquing of the
valve body bolts. They are very sensitive to correct torque
and do not torque nearly as tight as a GM trans.
Lugnut.
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