vinny R

Hi all, Well I have something strange is happening and will try to describe it as best as possible. When the car shifts gears (700R4) it feels like a "weight" shifts under the car and causes it to feel like the rear wants to break lose. Of course the rear does not as I don't have a high HP engine and this issue just started a few months back. If I downshift as I am moving i feel it also on the down shift just not as pronounced. There is no noise when this happens. The harder the shift (up or down) the more the force I feel on the weight shift. If you had a 400+ hp car that hooks up on a gear shift and tourque throws the cars weight to the side, that's what I feel, but since I don't have the HP it feels like something is lose.

When I push on the car side to side it is tight. I just had new rear springs installed along with LCARBs and a new urethane torque arm bushing and trans mount. The rear suspension is tight and the problem was there before I did this. I had new tires on the front and an alignment where they checked out the front suspension and all that is good. I feel the kick is in the rear, or that is where it ends up. I have urethane bushings and founder's performance parts in the rear and all that is good. I did the power break test and did not feel or hear the motor or trans move, the rear wheels broke lose and started a burnout, both wheels locked, so all is normal there. I will say that after the new TA and Trans Mount bushing it does not seem as bad.

In my past experience with broken mounts you usually here a clunk when the power is transferred. Could a bad engine mount case this? Bad torque converter? Trans or rear end about to blow?
This is really weird, it feels like something is broke in the suspension when the car shifts gears.

Thanks and all opinions welcome.

Vader

It seems that you have covered many of the usual suspects. Is the trans crossmember tight?

vinny R

I believe so, my mechanic did the mount and would have said to me if it was loose when he changed it.

vinny R

An update. I think it's in the trans with the way it is shifting. I adjusted the TV Cable and it made a difference. It now shifts quicker and does not seem to "kick out" like it did. I only got to drive it a short way.
The trans was shifting slowly, almost like it would "wind up" before the shift and then shift "heavily" and slide into the next gear. After this adjustment it is more of an instant shift and not "heavy" or slow. I put a new TV Cable on the car about 2 yrs or so back and when I completed this adjustment I am at the end already. Could my trans be on it way out? Can the Throttle Valve be replaced on the trans?

Vader

The throttle valve can be replaced in the transmission, as well as the sleeve spool surrounding it. The general instructions are outlined here: https://www.jegs.com/InstallationIns.../130-70237.pdf

vinny R

I found the problem and it is in the transmission. Hopefully no down the road damage has been done to the trans. About a year or so ago I was having a problem with the lock-up solenoid. I bought a replacement and had my mechanic put it in. He over filled my tranny by 1+ qts! OUCH. I never checked the level myself and there was no problem until 4-5 months ago. I never thought to check the level during this problem cause it did not slip which is usually a symptom of low fluid. I did a search of overfill syptoms and sure enough a "lunge" effect will happen upon shifts.
I got a boat gas tank primmer pump ball and put the hose down the dip stick tube and pumped out the overfill. Took it for a short drive around the block and it seems normal now.