350 turbo vacuum modulator problem - Impala Tech
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post #1 of 3 (permalink) Old 11-18-2013, 12:38 PM Thread Starter
Join Date: Nov 2013
Location: North Carolina
Posts: 12
350 turbo vacuum modulator problem

Hi everyone its me again and I have a new issue. I was test driving my 69 Impala today and it did'nt want to shift gears so I turned around and headed back to my drive way, I figured it must be low on trans fluid. Before I could get back to my house( about 200 yards or so) it started blowing white smoke from the tail pipes. I thought I blew the motor, but when I got home I could tell it smelled like trans fluid so I looked for a leak but found nothing. Untill I checked the vac line to the modulator. It was full of fluid and was being sucked into the intake where it hooks up.(Failed modualtor!) Now here is my quistion... I looked online to replace it and found modulators that said were for a 350 turbo trans but they look different than mine. Mine is large and has the hose nipple on the side, all the ones they show are smaller and have the nipple at the back. Will the smaller ones work or will I have to have the bigger one. Advise please and thanks beforehand for your muchneeded help!
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post #2 of 3 (permalink) Old 11-18-2013, 01:02 PM
Join Date: Jan 2006
Posts: 12,455
First thing to do is to verify the year and model of your transmission. There are code numbers stamped into the case above the tranny's oil pan on the drivers side , They could be stamped in different locations if your tranny was built at a different time or at a plant I am not familiar with as the vary, but most are on the case as described.

This is important to find the correct part as your tranny may not be original to your car (though in 1969 they were also stamping partial VIN numbers into the case so that is easy to determine). Because 1969 was the introductory year for the TH350 there have been a lot of changes made to the TH350 before it was finally discontinued; so those parts may be a direct bolt in using a newer variation of the part you want.

If so you may have to do a lot of web surfing to find someone who makes a replica of the original part.

Big Dave
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post #3 of 3 (permalink) Old 11-18-2013, 01:28 PM Thread Starter
Join Date: Nov 2013
Location: North Carolina
Posts: 12
Thanks Big Dave , I will look for the codes and see what I come up with. One of the small ones I found says it replaces the bigger one but I wanted some sound advice before I ran out to get it. Its only 20 bucks but I would'nt want to waist it on a part that did'nt fit or work right.
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