What causes SHUDDERING at 35-40mph (3rd gear)
Thread Starter
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True Car Nut
Joined: Jul 2004
Posts: 7,545
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From: Twin Falls, Idaho

Originally Posted by big_news_1
Originally Posted by 1993 SLE
the TCC is unlocked at 42 on a flat road light throttle, it will lock at about 48
I will look into the coil packs.
I forgot you drove an Olds.... well, the title of your post says third gear, and from what I remember there is TCC lockup in 3rd as well as 4th.......
How'* this for a theory: due to the shorter final drive ratio in the Olds 88, the "surging" TC problem I experience in overdrive manifests itself in 3rd gear for Hans? Did that make any sense?
If it only does it when warm, think about coil packs and then a tranny cooler. DON'T throw parts at it..... just find a set of good coils to try for an hour or two. I'll be surprised if it helps, but then again I'm not witnessing your problem firsthand. I'll let you know what my tranny cooler does for me when I get it installed in a couple weeks.
In the meantime, is my theory possible or am I thinking about it wrong?
How'* this for a theory: due to the shorter final drive ratio in the Olds 88, the "surging" TC problem I experience in overdrive manifests itself in 3rd gear for Hans? Did that make any sense?
If it only does it when warm, think about coil packs and then a tranny cooler. DON'T throw parts at it..... just find a set of good coils to try for an hour or two. I'll be surprised if it helps, but then again I'm not witnessing your problem firsthand. I'll let you know what my tranny cooler does for me when I get it installed in a couple weeks.
In the meantime, is my theory possible or am I thinking about it wrong?
Thread Starter
Senior Member
True Car Nut
Joined: Jul 2004
Posts: 7,545
Likes: 1
From: Twin Falls, Idaho

Originally Posted by big_news_1
I forgot you drove an Olds.... well, the title of your post says third gear, and from what I remember there is TCC lockup in 3rd as well as 4th.......
How'* this for a theory: due to the shorter final drive ratio in the Olds 88, the "surging" TC problem I experience in overdrive manifests itself in 3rd gear for Hans? Did that make any sense?
If it only does it when warm, think about coil packs and then a tranny cooler. DON'T throw parts at it..... just find a set of good coils to try for an hour or two. I'll be surprised if it helps, but then again I'm not witnessing your problem firsthand. I'll let you know what my tranny cooler does for me when I get it installed in a couple weeks.
In the meantime, is my theory possible or am I thinking about it wrong?
How'* this for a theory: due to the shorter final drive ratio in the Olds 88, the "surging" TC problem I experience in overdrive manifests itself in 3rd gear for Hans? Did that make any sense?
If it only does it when warm, think about coil packs and then a tranny cooler. DON'T throw parts at it..... just find a set of good coils to try for an hour or two. I'll be surprised if it helps, but then again I'm not witnessing your problem firsthand. I'll let you know what my tranny cooler does for me when I get it installed in a couple weeks.
In the meantime, is my theory possible or am I thinking about it wrong?
I am fairly sure it is something with the memcal what do I do to mess with this?
note what 93 sle said who has the identical drivetrain.
Completely rule out ignition before anything else. Swap coils from another 3800 in good running condition, and measure your 'new' plug wires for resistance. Post the resistance of each wire here (from shortest to longest).
Most problems like yours are ignition, although some are actually trans. The reason you feel it at that speed, is that you're low in the power band in 3rd gear at that speed, and it makes it easier to feel it. Normally you can feel it in OD under light throttle on a big hill as well, but not always. It takes a delicate foot to feel it without causing the TC to unlock.
Most problems like yours are ignition, although some are actually trans. The reason you feel it at that speed, is that you're low in the power band in 3rd gear at that speed, and it makes it easier to feel it. Normally you can feel it in OD under light throttle on a big hill as well, but not always. It takes a delicate foot to feel it without causing the TC to unlock.
Its got to be ignition or timing related. Took my 96 out for a long drive yesterday
and it didn't shudder once since I tweaked the TPS voltage.
Maybe it was grabbing OD too soon before. I noticed it upshifts easier now than it used to. It used to try to hold the gear and excelerate.
and it didn't shudder once since I tweaked the TPS voltage.
Maybe it was grabbing OD too soon before. I noticed it upshifts easier now than it used to. It used to try to hold the gear and excelerate.
Originally Posted by SSEBONNE4EVA
It used to try to hold the gear and excelerate.
That'* EXACTLY what mine does sometimes.... it'll lockup in OD too soon and then try to pull through it at low RPM without unlocking. It'* like I have to give it 3/4 throttle before it'll finally unlock or downshift to pull it'* own weight. Otherwise it'll sit there and surge while it slowly accelerates in OD. That'* very interesting.... I think I'll definitely adjust my TPS soon, plus give the car a good scan to make sure she'* running right.
My beef with that theory is that I never log a CEL when it'* surging, and let me tell you, it surges in a pretty big way. At least 200-300 RPM jumps when it'* acting up. I would think if it'* ignition-related I would see a CEL under those conditions.
My other argument is that it only does it when hot and I know it'* not the coils. Those have been replaced with MSD 8224s to no avail. If you'll reference my other posts about this issue you'll find that my surging has been gone all winter, and has only returned since the temperature has been in the 70'* consistently. The first time I had surging problems this year was when I took the car on the backroads for some VERY hard driving. I beat on that tranny with hard acceleration and high top speeds for only 10 minutes, and by the end it was surging like crazy. However, the surging calmed down after I drove it easy on the highway for a while. This leads me to believe it'* a heat-related tranny issue and the cold winter months provided enough cool airflow through the radiator to keep things happy. Now that it'* warm outside I'm not getting enough heat dissipation to let things cool off.
Sorry about the long post... I know we've already debated this thing into the ground, but I strongly believe I have a tranny cooling issue. I think heat is definitely a contributing factor here, and maybe I've got a combination of a few different problems. One thing is sure: I'm not going to let the car get away with this!
I will track this problem down and hopefully offer some concrete solutions for future users.
Originally Posted by SSEBONNE4EVA
Mine was just a chuggle where it was an uneven accelleration like the lockup going in and out.
I've got a similar shudder, anywhere from 35-50 mph, and is unaffected by hot/cold, it'* all the same. I've tried plugs, wires, coils, ICM, EGR, more tranny fluid, none of which fixed it. I can avoid the shudder with lots of throttle or not much.





