Since installing my 2200 rpm stall converter, my once very positive wheel chirping shifts feel week and soft....

Would the higher stall cause this?

 

Instead of me explaining it all I found this for you this to read. I totally hopped up my th350 and broke it drag racing with a 3800 stall 10 inch


You have the valve body and plate that can make the shifts so hard that it chirps even at low throttle

http://www.hotrod.com/techarticles/t...n_tuning_tech/

 

It all depends on what kind of power you have in the motor. If you running a stock L82/L48 those are specifically tuned to run a stock converter. If you know all of this please disregard.

Anyways you need solid HP in the engine to drive that 2200 rpm stall converter. For example I run a Yeoman 355 pushing 450hp. My stall converter is a TCI 2400 rpm which matches well off the line. However, seeing you are matching the RPMs to the engines power band on launch you should get more of a shooting out of a cannon effect because the engine dosent need to build RPMs as you get off the line, it's already there upon launch.

One note.....in reading some of these forums there was talk of the CLUNK when shifting into drive or reverse which I also had with the L48 and stock converter. Once I transitioned to the 355 and a stall my clunk was gone, matter of fact it now shifts better than my Silverado. But with the stock converter being so tight you will get wheel cherp when shifting gears the 2200 rpm stall you have is considerably looser than what you previously had in there. Hope this make sense some may disagree with my thoughts but I know what my car does now and what it used to do and there is a HUGE difference. Just be sure you have the power in the motor to move that stall converter as it's designed to do.

Beau

 

WHAT TRANS are we talking about ?

I would check the fluid level , also make sure the filter is seated correctly and did not get dislodged while swapping the torque converter.

 

I'm sorry, I should know you guys would want to know what trans it is...

It's a TH350 I had rebuilt 5000 miles ago with a valve body shift kit. Until I installed my 430 hp stroker and added the 2200 rpm stall, it had a very positive wheel chirping shift. Now feels soft and mushy. Fluid is full. No other changes.

 

With no other changes I would lok at the vacuum modulator. They make a lower vacuum model

 

Are you talking about part throttle shifts or wide open throttle shifts? Big difference in the way my trans shifts with 3k stall converter. Part throttle is pretty mushy, WOT very positive with a big bark in 2nd. I think that's normal.

 

He really has a little stall , stock is usually 1800 .. So with 2200 I just cant see mushing the shifts out as he says it is doing.

He says wheel chirping shifts , so I have to guess he is 5k or greater at the shift and at that speed the t/c is locked it should shift wot pretty much the same as it did before. Now under very light load it may feel soft but is should still be the same fast shift as before you just wont get the neck snapping shift like you use 2.

 

That's kinda what it's like. No hard positive shift under normal driving....very soft smooth shifts. Can't go WOT yet, engine only has about 12 miles on it. I've got on it a "little" but the shifts are still very mild.

I'll double check the vacuum line.....that's a possibility.

Something is different for sure.

Thanks guys.......

 

As mentioned above when changing to the stall converter my shifts are very smooth.

 

Vacuum modulator first. Did you upgrade your vacuum advance can on the distributor and do a performance recurve? The new engines cam has a lot higher operating range with lower vacuum. Power under that operating range will be less than your L48. Peak HP is great but if it is at a much higher rpm than your used to this is the result. You have 3.08 rear gearing. That combined with an automatic combined with a much higher operating range =noticeable loss of performance below that operating range. It would be even more noticeable with a stock convertor. I think I brought this up when you posted about your engine choice in a different thread and your reason for the convertor upgrade. Once you can do WOT shifts it will seem much better.

 

Well, I'll have to break this thing in and try some WOT shifts and see how I like it

 

If that's a new motor you should know how it shifts at 5k already. Motor break in should include climbing up the gears under load.. Not driving like your hauling eggs.

 

[QUOTE=diehrd.. Not driving like your hauling eggs.[/QUOTE]

 

LOL .. I try to be funny ,, sometimes it offends. I have poor social skills so it is nice to see I got that one right

 

No......that was funny

 

Your part throttle shifts are going to be controlled by the vacuum modulator. Get an adjustable one if you don't already have one. This way you can set how you want it to shift at part throttle. The bigger cammed engine is going to produce less vacuum than you stock motor changing the quality of your shift unless adjusted with modulator.
My 2400 stall TC still shifted as firm as I wanted it to with stock motor and then again with modded motor part throttle and full throttle. Just had to adjust the modulator to get what I wanted.

On another note and somewhat disputed, you need to warm up that motor and then drive it like you stole it to break it in. This is very important for ring seal. Accel hard and decel hard shifting down as the engine decelerates. Keep the pressure in the cylinder to force the rings to the wall of the cylinder.
Unless you have a broken in crate motor or something then drive however you want.

 

You have a high stall speed converter. It won't "grab" until it reaches that stall speed. Chirpy, low speed take-offs are gone forever....

 

I will say this, I got on it just a little from a dead stop and the back wheels lit up REAL easy