: "stuttery" or "bucking" feeling on 93 Fleetwood...need help!



CADDYDADDY13
09-26-10, 12:18 AM
Well i am having a problem with my 93 Fleetwood.
The car is in really really nice condition with only 62K miles on her.

Before i put her away for the winter in november last year i noticed this kind of "stuttery" or "bucking" feeling in the car when she would get up to 48 MPH and above. It seemed to be right around the shift point speeds. The car would drive fine, then when you started getting up to speed at 48MPH would kind of "BUCK".

It would kind of jerk the car, almost like the wheels in the rear were locking up, or something was kind of stuck on the wheels....
Like going over bumps or something.

Well i put the car away the next day, and got her out in summer this year, around mid June.
She started up, and I drove her home. She acted up at 48ish MPH. doing what she had done just before i put her away last year and scared me so i stayed driving at about 45MPH and under. i never put fuel additive in her so the gas was kind of bad, but she made the 15 minute drive home, she started acting up like the gas was bad right when i pulled into town, but drove fine most of the way except for that "bucking" feeling over 45mph.

So i called my mechanic and made an appointment to bring her in. That night i filled her up with fuel system cleaner and super premium 93 gas.
The next morning when i went to take her in the drive was 45 and under so i did the speed limit, just a short ride to shop. GAs seemed to be cleaning out and running good. but i didnt travel over 45mph because i was afraid the feeling i had felt would hurt car.
So later that day mechanic calls me and says, he cant find or feel antyhing wrong with car. says come on down and take for a ride, then if she does it pick me up and we'll ride together, so i go and take her out. NOTHING! she runs fine, flawless... take her for a 20 minute ride doing from 30mph-85mph..

Mechanic says maybe it was a brake shoe or something that stuck...and let go finally
OK... SO I DRIVE HER FOR THE NEXT MONTH PROBLEM FREE.

In august i took her on over a 1,000 mile trip to new jersey. NO PROBLEM!!

But a week later i take her on about a 2 hour ride and she starts acting up again...
Starts acting up around 48mph, and then around 55 or so, and so on. If i really gun it(step on the gas) she powers through the feeling and goes, but acts up once you slow down and speed up again.

So i was thinking that maybe it was the gas not fully out, or bad, or since fuel was low since it aseemed as thought evry time this happened the gas was at about a quarter tank or so... but filled her up and 2 days later doing it again....with full tank!

Could it be a bad fuel line, or tranny line? Fuel pump? Car is very clean and rust free... no drips or leaks... Cant imagine tranny is bad.... It really scares me when she does it, and makes me mad since she is in such good shape otherwise.

Any thoughts? or ideas at where to look?

Mechanic cant help since he cant feel problem.

Stingroo
09-26-10, 12:54 AM
My wagon did this for awhile too... it just kinda goes in and out.

csbuckn
09-26-10, 03:25 AM
Sometimes a sign of ignition problems. When is the last time the wires, cap, coil, plugs and rotor were changed?

turbojimmy
09-26-10, 08:11 AM
I would guess the TCC lockup solenoid is not holding. If you give it gas, it will cancel the lockup request and it will be fine. I don't know what the lockup is on the Fleetwoods, but on my Buick I think it was around 38-40 MPH. Once you hit that speed with no load, it will try to lock up the converter. If the solenoid is weak or intermittent, it will lock/unlock the converter rapidly causing it to feel like it's bucking/shuddering.

Stingroo
09-26-10, 09:05 AM
Hmmm....

CADDYDADDY13
09-27-10, 12:17 AM
I would guess the TCC lockup solenoid is not holding. If you give it gas, it will cancel the lockup request and it will be fine. I don't know what the lockup is on the Fleetwoods, but on my Buick I think it was around 38-40 MPH. Once you hit that speed with no load, it will try to lock up the converter. If the solenoid is weak or intermittent, it will lock/unlock the converter rapidly causing it to feel like it's bucking/shuddering.

I have never heard of this... When you say lock up what exactly do you mean? What your saying sounds like maybe what is wrong with my car... are there multiple lock up points?

turbojimmy
09-28-10, 12:53 PM
I have never heard of this... When you say lock up what exactly do you mean? What your saying sounds like maybe what is wrong with my car... are there multiple lock up points?

The transmission has a "lock up" torque converter that improves fuel economy at highway speeds. A torque converter's job in an automatic transmission is to join the engine to the rear wheels through a always-slipping, fluid clutch. On modern vehicles, at a predetermined speed and below a certain throttle %age, a clutch inside the transmission's torque converter essentially locks the engine to the wheels at a 1:1 ratio, eliminating all of the slippage (and the inefficiency associated with the slipping). It feels like a gear shift, but it's actually a lockup. This results in better fuel economy due to the lower, consistent RPMs at cruise. When you press the gas pedal past a certain point, the converter unlocks (feels like a downshift), allowing it to slip again and letting the engine inrease RPMs up into its power band. The lock/unlock is accompished via an electric solenoid inside the transmission that operates a plunger that changes the flow of fluid through the converter. GM is notoriously bad at manufacturing a reliable solenoid. Over time the solenoid and its connection deteriorates from being soaked in hot oil all the time. The solenoid starts to operate intermittently, locking and unlocking the converter causing the car to feel like it's bucking or shuddering. Again, if you press the pedal to a %age beyond the unlock point, it will stay unlocked and it will feel fine. Eventually it will fail completely. It will set a code because the PCM knows it called for a lockup and compares engine speed to road speed. If it gets an inconsistency, it will throw on the SES light. This is particularly problematic in the FWD Devilles where GM cleverly placed the $15 solenoid in a place that requires $3,000 in labor to get at it. On a RWD car, you just need to drop the transmission pan to replace it (which is a major reason why, after having owned several Devilles, I am currently seeking a Fleetwood).

CadillacZach77
09-29-10, 11:54 AM
What's the correct name of that solenoid and what does it look like? Mine stutters sometimes around 45 mph.

turbojimmy
09-29-10, 03:33 PM
What's the correct name of that solenoid and what does it look like? Mine stutters sometimes around 45 mph.

It's ususally referred to as the TCC solenoid (Torque Converter Control). It's inside the transmission, in the valve body. Here's the one in my Deville. They all look similar:

http://turbojimmy.4t.com/tcc_replace-12.jpg

http://turbojimmy.4t.com/tcc_replace-13.jpg

Jim

albymangled
09-29-10, 07:06 PM
I reckon a set of plugs, leads, dizzy cap etc are a none too expensive start if it is so expensive to get at the solenoid....

turbojimmy
09-29-10, 08:15 PM
I reckon a set of plugs, leads, dizzy cap etc are a none too expensive start if it is so expensive to get at the solenoid....

Actually it's easy on the RWD cars. You might have to take a tranny fluid bath (a known carcinogen in the state of California), but it's real easy to get at. The problem is in the FWD Devilles - thousands of $ in labor to get at it.

CadillacZach77
10-11-10, 12:41 PM
So, if I drop my pan on my fleetwood what comes next? Just pull the old solenoid out and pop the new one in? Are there any special tools or anything else I should know about? I just don't want to drop the pan and then not be able to finish the job.

turbojimmy
10-11-10, 02:27 PM
Basically yes. The shop manual shows about 2 hours of labor. I don't have a pic, but I do have instructions:

1. Raise and support vehicle.
2. Disconnect heated oxygen sensor.
3. Remove catalytic converter to muffler attaching bolts and nuts.
4. Remove catalytic converter hanger to catalytic converter bolts.
5. Remove righthand side dampener assembly.
6. Remove nuts holding exhaust pipe to exhaust manifold.
7. Remove converter and pipe assembly from vehicle.
8. Remove oil pan and oil filter assembly.
9. Disconnect external wiring harness from transmission pass through connector.
10. Remove accumulator cover attaching bolts.
11. Remove 1-2 accumulator cover, piston and spring.
12. Disconnect electrical connectors.
13. Remove pressure control solenoid retainer bolt, then the retainer and solenoid.
14. Remove TCC solenoid retaining bolts.
15. Remove pass-through electrical connector from transmission case by positioning the small end of power piston seal protector and diaphragm retainer installer tool No. J-28458 or equivalent, over the top of the connector, then twist tool to release the four tabs while at the same time pulling the harness through the case.
16. Remove TCC solenoid with wiring harness from transmission case.
17. Reverse procedure to install, noting the following:
1. Tighten TCC solenoid retaining bolt to specification.
2. Tighten pressure control solenoid retaining bolt to specification.
3. When installing 1-2 accumulator piston to accumulator cover, the piston legs must face towards the case.
4. Tighten accumulator attaching bolts to specification

CadillacZach77
11-08-10, 01:35 PM
So I'm going to be replacing the lockup solenoid. From reading this:

http://www.gmtruckhq.com/?q=node/93

It sounds like I need a new TV boost solenoid because it does take the fleetwood a few seconds for reverse to engage after shifting to it. I figured while I had the pan off i might as well replace it but this site says there are three different "boost" solenoids:

http://www.hotrodders.com/forum/4l60e-pressure-regulator-boost-valve-150830.html

Can anyone elaborate on the difference in these solenoids?

outsider
11-08-10, 01:59 PM
woah wait...you have to drop your exhaust to do the tranny pain drop? :O

Is it that way on a 95 also? I still haven't done my tranny filter/fluid (i know...had the parts and fluid for over a month now...) but when I looked it didn't look like the exhaust was in the way!

Stingroo
11-08-10, 02:45 PM
Wait, question:

Does the '93 Brougham have factory dual exhaust like the '94-96? I know in the wagon-world the TBI cars don't, and the LT1 cars do. Is it the same for the Cadillacs?

CadillacZach77
11-09-10, 10:08 AM
woah wait...you have to drop your exhaust to do the tranny pain drop? :O

Is it that way on a 95 also? I still haven't done my tranny filter/fluid (i know...had the parts and fluid for over a month now...) but when I looked it didn't look like the exhaust was in the way!

Turbojimmy's instructions must be for a Deville. It's not nearly that much work on a Fleetwood. All you have to do is drop the pan and remove the filter. If you have a late model 4L60E you also have to remove another solenoid to remove the TC lockup solenoid:


http://www.youtube.com/watch?v=6Svl0fDl1qI&feature=channel

I couldn't figure out how to get the pwm-tcc solenoid out but after watching this video it's held on by a metal clip. I wonder if I should replace this pwm-tcc solenoid or any of the other ones?

turbojimmy
11-12-10, 07:19 AM
woah wait...you have to drop your exhaust to do the tranny pain drop? :O

Is it that way on a 95 also? I still haven't done my tranny filter/fluid (i know...had the parts and fluid for over a month now...) but when I looked it didn't look like the exhaust was in the way!

I dunno. The instructions I posted were for my '96. I haven't actually been under the car to look at it. I'd be surprised if the exhaust was in the way, but that's what the FSM said.

turbojimmy
11-13-10, 06:29 PM
I dunno. The instructions I posted were for my '96. I haven't actually been under the car to look at it. I'd be surprised if the exhaust was in the way, but that's what the FSM said.

Okay - the FSM is wacked. There's no need to mess with the exhaust. I was under there today and you can remove all of the pan bolts and drop it down with no interference from the exhaust. Those instructions were right from the FSM for my '96 Fleetwood. Go figure.