1978 F-100 tranny problem

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

snuffy - 26 Jan 2006 04:30 GMT

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?

Reply to this Message

pkurtz2 - 26 Jan 2006 05:44 GMT

> Just had this transmission rebuilt by someone who does an excellent job
> on GM transmissions, but obviously not so good with a Ford
[quoted text clipped - 3 lines]
> say "I dunno...something ain't right." Any clues as to why this shift
> is so screwy? Band adjustment? Modulator valve out of adjustment?

Sounds like it needs its break in adjustments. Just like an engine,
everything in a tranny needs to be broke back in once its overhauled. See if
he can adjust the bands alittle tighter and that might make up for some
lag... But I dont know a whole lot about automatics..

Reply to this Message

Kevin Bottorff - 29 Jan 2006 22:41 GMT

>> Just had this transmission rebuilt by someone who does an excellent
>> job on GM transmissions, but obviously not so good with a Ford
[quoted text clipped - 9 lines]
> See if he can adjust the bands alittle tighter and that might make up
> for some lag... But I dont know a whole lot about automatics..

the c6 doesn`t use bands, he screwed something up. pull it and fix it.
KB

Signature

ThunderSnake #9 Warn once, shoot twice
460 in the pkup, 460 on the stand for another pkup
and one in the shed for a fun project to yet be decided on

Reply to this Message

lugnut - 30 Jan 2006 02:36 GMT

>Just had this transmission rebuilt by someone who does an excellent job
>on GM transmissions, but obviously not so good with a Ford
[quoted text clipped - 3 lines]
>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.

Reply to this Message

Rate this thread: