Just replaced Tranny modulator, now i got shifting problems - HELP!

[T3hN1cksta]

Today i replaced my Vacuum modulator on my transmission and before i replaced it the car shifted flawlessly, the old modulator was leaking so i was losing fluid, and today i installed the new modulator and now it shifts really wierd. Heres what happens : it'll shift from 1st to 2nd, and then at around 15mph while accelerating it'll downshift and then it'll shift into 2nd again. I topped off my tranny fluid level after installing the new modulator (yes i put the original pin into the new modulator) and ive checked the vacuum line and its connected on both ends. Anybody know what could be causing this? I really dont want to end up burning my tranny out

 

[mrjoe16]

Im still new to the transmission thing but as I have red in this forum you have to readjust the bands. Im not sure what the torque spec is and how much you need to back them off and lock down the lock nut. If you do a search on band adjustments youll get it shifting smooth.

 

[bcbid]

I posted this in the other thread. Have you checked your engine oil? when my modulator went bad . That is where the tranny fluid went. Mine worked fine after I changed it.

 

[BrooklynBay]

Did you clean the bore with a wire brush, and WD-40 prior to installing the new modulator? Is the new modulator adjustable or non adjustable? Did you clean the vacuum line with Seafoam?

 

[T3hN1cksta]

Its not leaking into my engine oil, it was leaking into the vac hose and going to my intake

I didnt clean the bore or vac hose before installing the new modulator. and Im pretty sure that my modulators non-adjustable. Would cleaning out the bore/ vac hose effect how the tranny shifts?

 

[BrooklynBay]

Everything has to be free of old fluid since old fluid is sticky, and attracts dirt. The pin & spool might bind if it's contaminated. Transmission fluid was drawn into the engine through the vacuum hose.

The adjustable modulator has a thumb wheel adjustment. Does the new modulator have a very small opening where the vacuum line goes? If not, then it's a C3 modulator which is the wrong part.

 

[DV8]

also, did you replace your mod valve with an adjustable aftermarket one? if it is, it will have a screw in the end near the vacuum connection. try adjusting the little screw, which is a real pain to get to with the valve on the trans. i had the same problem, and that is what i did to fix the problem.

 

[T3hN1cksta]

DV8, which way did you turn yours? We adjusted mine clockwise and its doing the same thing still, should i try adjusting it the other way? Counter clockwise was for rough shifting, and clockwise was for soft shifting/slipping (which is what we adjusted mine to, its adjusted to the max 4 turns, we did it in intervals, 2 turns then tested, 3 turns then tested, and 4, and its still doing the same thing)

 

[DV8]

i dont remember which way i had to turn it, but if it really made no difference, you may have a faulty valve. it does happen. i can personally attest to that, as i sell parts for a living.

 

[T3hN1cksta]

It did effect how its shifting, but it didnt fix the problem with my tranny shifting back into 1st gear halfway thru 2nd gear

 

[T3hN1cksta]

Update: yesterday i came outside to get in my car and i noticed a large puddle of fluid underneith my car, upon further inspection its leaking large amounts of transmission fluid from somewhere around the modulator, and now every time i turn the car off within 15-20 minutes a large puddle (about as big as a sheet of printer paper) will appear underneith my car,could this have been caused by us adjusting the modulator??

 

[BrooklynBay]

Check underneath to see where it's leaking from.

 

[T3hN1cksta]

I found where it was leaking, one of the pan bolts became really loose, tightened it up (and made sure the rest were tight) and it fixed the leak.

 

[T3hN1cksta]

Does the pin in the modulator have to go set in a specific spot inside the bore of the transmission? because everywhere ive taken it everyones said check to makesure i re-installed the pin, and i did. When i re-installed the modulator i placed the pin in the modulator and installed it that way, does the pin have to seat in a certain spot/position in the bore?

 

[BrooklynBay]

The pin has to go into the modulator first.