TH400 PROBLEM - PART II

shvrolay

Dragway Regular
OK........I'm re-installing the valve body into my TH400 and checked to make sure 'how' the front servo assembly was installed into the case.
I found two different pictures of how it should be installed.........in the same book!! The ATSG Techtran Manual.
One shows the spring against the accumulator piston (with the blunt end of the pin into the case), the other shows the servo piston against the accumulator piston (with the taper on the pin facing into the case at the band).

Which is correct?

front%20servo0002%20-%20Copy.jpg
front%20servo0003%20-%20Copy.jpg


Hope this isn't too confusing.

TIA
 
I think the confusion lies in the first picture where you see the accumulator below the servo and pin assembly. The accumulator is always in the valve body. Both pictures are actually the same. Reference the picture to the right for final assembly.

As a side note, TH400's that feature a steel front servo piston require the accumulator with the three stands as seen in the first picture. TH400's that feature an aluminum front servo piston require an accumulator that is flat (no stands).

Hope this helps.
 

shvrolay

Dragway Regular
Thread starter
Thanks for the response Pete, but I respectfully beg to differ.........the pictures aren't the same. One has the servo spring against the accumulator piston, the second pic will have the servo piston against the accumulator piston once the VB is installed. What is shown in the second pic is the trans case, not the VB.
 
The first picture is not instructing you to install the spring against the accumulator piston. It's merely showing a picture of the accumulator piston that is required for use with the servo parts that are pictured. It bears no relevance to the order of assembly. I understand why it's confusing, but the accumulator picture is simple a reference item, not part of the assembly picture.
 

shvrolay

Dragway Regular
Thread starter
..........thanks Pete, that makes sense and I think I was slowly coming around to that.
I was over-thinking this/trying to re-invent the wheel maybe.

Thanks again for your time and patience.
 

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