Auto trans shudders during mid throttle downshift
Thread Starter
Instructor
Joined: Mar 2001
Posts: 199
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From: Canyon Lake California
Auto trans shudders during mid throttle downshift
Yesterday, while test driving the new power steering pump, I stumbled across a new problem. At about 45 MPH, going slightly uphill, I pushed the throttle down gradually until it downshifted from 3rd gear to 2nd gear. When it downshifted, there was a distinct continuous shudder coming from the trans. As soon as I lifted my foot off the gas, the trans upshifted and the shudder went away. Under normal stop and go driving, the trans acts normal. The synthetic trans fluid is clean and at the proper level. The trans is a rebuilt with about 82,000 miles on it. The original trans made it to 90,000 before I fried it at the drag strip. Haven't had this tranny to the drags. We don't race this Vette anymore...it now functions as my wife's daily driver.
Here's the question: Should I assume that the shudder marks the beginning of the end for this tranny? Or is there possibly something less serious causing this kind of problem? Have any of you had the same experience?
Thanks in advance,
Greg Sullivan / Canyon Lake, CA.
[Modified by Greg's '88, 11:36 AM 2/10/2003]
Here's the question: Should I assume that the shudder marks the beginning of the end for this tranny? Or is there possibly something less serious causing this kind of problem? Have any of you had the same experience?
Thanks in advance,
Greg Sullivan / Canyon Lake, CA.
[Modified by Greg's '88, 11:36 AM 2/10/2003]
Burning Brakes
Joined: Aug 2002
Posts: 926
Likes: 2
From: chandler az
Re: Auto trans shudders during mid throttle downshift (Greg's '88)
45 mph is the point when the torque convertor locks up or it shifts into overdrive - I can't remember which. one event happens at 33mph the other at 45mph. I have pounded the throttle once when it was doing its hunting and it felt like it couldn't decide what to do. Just my experience.
Thread Starter
Instructor
Joined: Mar 2001
Posts: 199
Likes: 0
From: Canyon Lake California
Re: Auto trans shudders during mid throttle downshift (brookman)
When it shuddered, it just seemed like 2nd and 3rd gears were fighting each other. Is the auto trans in 88's called a 4L60E?
I'm going to start shopping around on the internet to see how much $$$ buys how much tranny.
I'm going to start shopping around on the internet to see how much $$$ buys how much tranny.
Thread Starter
Instructor
Joined: Mar 2001
Posts: 199
Likes: 0
From: Canyon Lake California
Re: Auto trans shudders during mid throttle downshift (JCAIRE2)
I was told that the torque converter was replaced...but I can't say that I watched him do it. I'm just taking the repair shop's word for it.
At more than 3/4 throttle, it still has a nice 1-2 upshift where it sometimes will chirp the tires.
I think the tranny is trying to give me fair warning that it is about to expire.
Where can I get a better than stock (but not full race) tranny for my '88?
At more than 3/4 throttle, it still has a nice 1-2 upshift where it sometimes will chirp the tires.
I think the tranny is trying to give me fair warning that it is about to expire.
Where can I get a better than stock (but not full race) tranny for my '88?
Advanced
Joined: Nov 2002
Posts: 77
Likes: 0
From: Calimesa California
Re: Auto trans shudders during mid throttle downshift (Greg's '88)
You could install a Trans-Go Junior Shift kit (modified) to solve this. There is nothing to worry about, if you happen to get into the same situation again, try moving the lever back to 2nd gear, this will make the intermediate/reverse boost valve active, thereby raising line pressure, and possibly eliminate the problem or avoid the situation if possible. If you have any questions on this let me know?
Burning Brakes
Joined: Jul 2002
Posts: 972
Likes: 0
From: Springdale AR
Re: Auto trans shudders during mid throttle downshift (Greg's '88)
Mine does the same thing. I've been told it is the Torque Converter. If yours is the torque converter it will get worse, for instance, mine started out just what you described, but now mine will do it mostly in overdrive, but it has done it even in drive when going up a hill when you get a load on the engine but you don't give it enough gas to down shift. One way to find out if it is the TC, is when you get it in that situation where you can make it shudder, keep giving it the same amount of gas during shuddering, but don't give it so much gas that it down shifts, then "lightly" tap the break at the same time while you are still giving it gas. If it is the TC the shudder will go away when you tap on the break. By tapping on the break it unlocks the TC and the shudder goes away.
