ATF Never Changed In 135K Miles - Leave Or Change It? - Automotive Repairs - Page 4 - DIY Chatroom Home Improvement Forum

Go Back   DIY Chatroom Home Improvement Forum > Do It Yourself > Automotive Repairs


Thread Tools Display Modes
Old 04-25-2013, 02:58 PM   #46
Join Date: Jan 2011
Posts: 107
Rewards Points: 83

I didn't remember the term "switch pitch", but then there are a lot of things that I don't remember at my age. It appears that the "switch pitch" transmission was a special version of the turbohydromatic 400. I rebuilt a lot of those which probably included the switch pitch as well. The primary differences were in the valve body and a different sized shift solenoid. I usually identified the transmission by the id tag on the transmission or by the specifications provided by GM. The primary problem with repairing a transmission of this type would be identifying the unusual shift pattern when testing for proper operation since the downshift and upshift behaved differently from other th400s. Anyone who could rebuild a TH400 should not have had a problem rebuilding a "switch pitch".

Here is some additional info:


davido30093 is offline   Reply With Quote
Old 04-26-2013, 06:00 AM   #47
r0ckstarr's Avatar
Join Date: Jan 2013
Location: SE Texas
Posts: 1,861
Rewards Points: 2,060

That's only part of it. Another primary difference (biggest difference) was the torque converter, which is where it got the name "switch pitch". The stator blades can change the angle to reduce friction in order to put the vehicle in motion. The effect feels like a major torque increase at full throttle. Most people who rebuilt the Switch Pitch tranny's didn't know enough about them, and replaced the Switch Pitch converter with a regular lockup converter.


r0ckstarr is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Synthetic oil changes leonuug Automotive Repairs 29 03-18-2012 05:49 PM

Top of Page | View New Posts


Search Engine Friendly URLs by vBSEO 3.6.1