is my torque converter going bad??

[bot0611]

I had a leake on my tranny but didnt put much attention to it due that i dont move the truck much, but now i can hear a hizz under there, not sure what it is, if i got from park to drive i can distinctly hear it going just like the engines revs (it gets quieter) if i go from D to P (it gets a bit luder)

 

[dyeager535]

Not likely the converter. Converter noise is usually existent when in park/neutral (low/no load on the converter) but disappears when in drive.\

Only thing to fail in a converter from lack of lubrication would be the bearings/thrust washers, and the above is the "test" for that problem.

 

[bot0611]

Oh ok, well i i checked everywhere for vacuum leaks ( someone mentioned that might be it) took off lines while engine running to see if the engine reacted and yep it did, pcv, brabe booster, advance on the dizzy, i doubt the intakes manifold gaskets are bad but then again the carbs im not so sure i already changed them due to wha seemed a leak.

Now what problem might the trannys modulator cause if the modulator is bad???? im just wondering

 

[dyeager535]

Modulator controls how hard a tranny shifts (at least on a TH350/400) and to a SLIGHT degree, at what RPM/vehicle speed it shifts. While a leaky/disconnected line would be a vacuum leak which could cause a bit of a problem obviously, if the modulator is bad, typically they will leak fluid (might suck it up to the engine and burn some) but with a busted diaphram, they will simply revert to harder shifting.

If you pull the vac line off the modulator and trans fluid comes out, good indication the modulator is shot.

 

[bot0611]

Thats the same line that goes to the manifold, well in my case i think it does, if so i took it off and the engines only reved higher

 

[dyeager535]

I never noticed any difference on my TH400 when the line came off either, but the modulator IS what controls the pressure inside those type of transmissions.