Go4DaMo Posted September 12, 2012 Report Share Posted September 12, 2012 I have a '93 Z34 that I'm experiencing this problem with: from a dead stop, the car chugs forward up to 5 MPH (engine revs fine, but feels like it doesn't want to accelerate). If I never drop below 5, 1st gear will pull fine! If I torque-brake at a stop sign up to 1500-2000 RPM, then ease away...the creaking and jolting is felt with the brake applied and the car will drive away flawlessly. This problem occurs in OD, D, 2, and Reverse. In 1st; it's slightly less messed up but makes a screeching sound if you stab the gas too hard from a stop. Can anyone help? Thank you so much! Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted September 12, 2012 Report Share Posted September 12, 2012 I'd check the modulator, and associated vacuum lines first...the modulator regulates line pressure, and if it's not working properly, all sorts of interesting things can happen. However, that "screech" you're describing doesn't sound like a related issue...when was the last fluid and filter change for your transmission? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted September 12, 2012 Report Share Posted September 12, 2012 putting the shifter in first causes a significant bump in line pressure. if i had to guess, i'd say that's what's the causing both the noise and the tendacy for less slip. Quote Link to comment Share on other sites More sharing options...
rich17 Posted September 13, 2012 Report Share Posted September 13, 2012 Add Lucas trans fix as well. Has saved 6+ trannies that I put it into Quote Link to comment Share on other sites More sharing options...
Go4DaMo Posted September 13, 2012 Author Report Share Posted September 13, 2012 Thanks, guys! is the modulator a mechanical or electrical part? never heard of it. can't wait to get this thing back in perfect working order! Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted September 13, 2012 Report Share Posted September 13, 2012 It's mechanical...works off of engine vacuum. It's on the driver's side of the transmission, Look for the round canister a little smaller in diameter than a soda can, with the vacuum line, near where the wiring for the trans connects to the transmission. That's the modulator. It's held on by a small "U" shaped clamp, by a single bolt. Thanks, guys! is the modulator a mechanical or electrical part? never heard of it. can't wait to get this thing back in perfect working order! Quote Link to comment Share on other sites More sharing options...
Go4DaMo Posted September 28, 2012 Author Report Share Posted September 28, 2012 easy fix, then? Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted September 28, 2012 Report Share Posted September 28, 2012 easy fix, then? Exceptionally easy. Disconnect the vacuum line, remove the bolt and clamp, and pull the modulator straight out. New one goes in, replace the clamp and bolt, reconnect the vacuum line--done. You'll spend more time finding the tool to remove the bolt, than you do replacing the modulator. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted September 28, 2012 Report Share Posted September 28, 2012 that's true. i pulled the one on the 90GP off to mess around with it to see if it was causing my hard and very late 3-2 downshift, took no time at all. turns out it wasn't the modulator, but the little rubber vacuum line right before the modulator was partially rotted, replaced that and it fixed quite a few issues. certain modulators have different "hats", some of which are easier to work with than others. Quote Link to comment Share on other sites More sharing options...
Go4DaMo Posted September 28, 2012 Author Report Share Posted September 28, 2012 woo hoo! maybe I'll fix it at the meet this weekend...kinda have a jampacked day today. THANK YOU ALL FOR YOUR HELP! Quote Link to comment Share on other sites More sharing options...
Go4DaMo Posted October 19, 2012 Author Report Share Posted October 19, 2012 Took to a shop recommended to me in Cuyahoga Falls, OH, and have been informed the trans is in need of a rebuild. A chain inside the transmission feels like it's skippin teeth! Employees were very impressed w the condition of the car and told me a blue 5speed Z34 was in years ago! Quote Link to comment Share on other sites More sharing options...
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