85 Eldorado - Violent shake at certain level of acceleration - Page 2
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Page 2 of 2 FirstFirst 1 2
Results 16 to 25 of 25
Cadillac Seville / Cadillac Eldorado Forum Discussion, 85 Eldorado - Violent shake at certain level of acceleration in Past Cadillac Vehicle Discussion; Originally Posted by carnut It also provides a visual inspection of both for possible missing weights. Are there weights on ...
  1. #16
    eyewonder is offline Cadillac Owners Fanatic
    Automobile(s): 2000 STS, 170K Miles
    Join Date
    Nov 2011
    Location
    SE Kansas
    Age
    65
    Posts
    173

    Re: 85 Eldorado - Violent shake at certain level of acceleration

    Quote Originally Posted by carnut View Post
    It also provides a visual inspection of both for possible missing weights.
    Are there weights on the flex-plate & torque converter? Or was that comment meant to address the example of tires?

    I don't remember seeing any weights on either the flex-plate or converter when I did my HG repair, but I'll go back through my photos & see if there are any shots that would show weights.

    Cheers,
    Steve

  2. #17
    carnut is offline Cadillac Owners Master
    Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
    Join Date
    Feb 2003
    Location
    california
    Age
    67
    Posts
    5,942

    Re: 85 Eldorado - Violent shake at certain level of acceleration

    Yes there are weights on both. Anything that rotates on a car must be balanced. Normally you dont have to index a torque converter to a flex plate but when one is unbalanced, the moving of the torque converter relative to the flex plate (flywheel) helps to narrow down the source of the unbalance. Moving is not a repair but rather a diagnostic step.

  3. #18
    eyewonder is offline Cadillac Owners Fanatic
    Automobile(s): 2000 STS, 170K Miles
    Join Date
    Nov 2011
    Location
    SE Kansas
    Age
    65
    Posts
    173

    Re: 85 Eldorado - Violent shake at certain level of acceleration

    This was a good day - I learned something new!

    Cheers,
    Steve

  4. #19
    carnut is offline Cadillac Owners Master
    Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
    Join Date
    Feb 2003
    Location
    california
    Age
    67
    Posts
    5,942

    Re: 85 Eldorado - Violent shake at certain level of acceleration

    Never heard back from this fellow regarding torque converter replacement? probably still driving it with the TCC harness unplugged. Posting the correction helps us all on this forum.

  5. #20
    Kiriken is offline Cadillac Owners Member
    Automobile(s): 1985 Eldorado, 2008 STS
    Join Date
    Mar 2009
    Posts
    26
    Thread Starter

    Re: 85 Eldorado - Violent shake at certain level of acceleration

    Sorry! I feel bad for not posting back sooner, you've been extremely helpful.

    My situation is basically this, I'm a college student renting a room from a married couple (they rent out several rooms). They're very accommodating when it comes to me working on my car, but I try to be polite about it. I stopped posted when some of their relatives came from Europe to visit and I decided to wait until they left before doing anything that involved jacking the car up. I thought they'd only be here for a few days, and I figured I'd post back when I had an update... Well it turns out they were staying here for close to 3 weeks (they just left yesterday).

    Anyway, there's not much to update on. I did unplug the TCC harness, but only on Friday (5 days ago), until then I was still driving around with the TCC shaking issue. My girlfriend lives about 3-4 hours away and she's been missing me since I haven't been driving down to see her because of the shaking (I was afraid the car was going to fall apart). Friday I unplugged the harness, crossed my fingers and drove from Santa Barbara to San Diego. Not a single vibration and my gas mileage stayed about the same (remember, before unplugging the harness my solution was to floor the gas pedal every minute or so when the lockup would engage and cause the shake). Drove back without any issue as well.

    I'd rather fix the issue than drive around with the TCC bypassed, but it's something I'm not sure is worth paying to have repaired. The car only cost me $1,500 and I imagine the repair would be at least 1/2 that. To answer your question about a bad torque converter being the reason it was sold, it's possible, but I don't think so. I drove it regularly for probably a year before I felt any shaking.

    The main issues with the car when I bought it were it needed a tuneup (brittle sparkplug wires, buildup on distributer cap, etc), 4 bad shocks, clearcoat mostly gone, paint somewhat "crazed" on the hood/roof/trunk (in dim lighting it's not apparent), bumper fillers falling apart, bald/cracked tires, scratches on the rear leather seats (previous owner had a dog?)... the usual. Those things made it a reasonable price. I do feel lucky that I haven't had an issue with overheating (I've read a lot about those issues). There was one day where all the "Engine Hot" warning lights came on and engine sounded like it was dying (limiting itself?). Turns out the rubber had rotted off of a wire which grounded the temperature sensor and set off all those alarms (electrical tape solved that). I've made sure to replace the coolant and & add the tabs from the dealership so I guess I'm doing what I'm supposed to do to prevent that.

    Never the less, I was an inch away from ditching the car before you suggested checking the torque converter. The car has 116,000 miles, engine was rebuilt after 44,000 miles I believe. From the HT4100 stories I've read, I imagine one with 72,000 miles on it after a rebuild is probably "fragile" at best. I'm not sure though because I've got some paperwork that indicates the rebuild was an official GM job, not a corner mechanic and from what I've heard the '85 year is probably the best HT4100 to have, so I really don't know how long to expect it to keep chugging for.

    Hopefully I'll find some time this weekend to do the torque converter rotation check you described. I see it now in the manual as well, originally I looked at a page with a full page diagnostic flow chart and the first thing my eye caught was "DISASSEMBLE TRANSMISSION AND CHECK FOR...." and that scared me into putting the manual away.

    Also, I found this video that explained everything pretty clearly in case anyone else is interested in how it works. At around 5:40 an annoying sound interrupts the video, but it goes away before 6:10 when he explains how the lockup works.



    To me it seems like the vibration would be caused by the physical clutch on the lockup "plate" shown in the video. The manual also has a big table in the 325-4L section (page 9?) which says "ROUGH CONVERTER CLUTCH APPLY" - Inspect "Converter Clutch Apply Valve Bushing" for "Orifice plugged". I suppose that could be the issue (or an issue) as well? I'm thinking now if there was an imbalance, wouldn't that be felt even when the TCC isn't in lockup?

  6. #21
    carnut is offline Cadillac Owners Master
    Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
    Join Date
    Feb 2003
    Location
    california
    Age
    67
    Posts
    5,942

    Re: 85 Eldorado - Violent shake at certain level of acceleration

    Thanks for the update! That should help others as well.

  7. #22
    carnut is offline Cadillac Owners Master
    Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
    Join Date
    Feb 2003
    Location
    california
    Age
    67
    Posts
    5,942

    Re: 85 Eldorado - Violent shake at certain level of acceleration

    I wouldn't waste the time to do the rotation at this point. If its smooth and working fine with the harness disconnected, leave it alone. The problem is internal within the torque converter.

  8. #23
    Kiriken is offline Cadillac Owners Member
    Automobile(s): 1985 Eldorado, 2008 STS
    Join Date
    Mar 2009
    Posts
    26
    Thread Starter

    Re: 85 Eldorado - Violent shake at certain level of acceleration

    Sorry to revive this old thread but there are some new developments.

    After driving around for almost a year with the transmission harness disconnected, I think the deterioration of the torque converter may have progressed. After a recent long drive the car began to stall at stoplights or when attempting to do parking that requires multi-point turns and/or shifting into reverse. The stalling usually only occurs after a 10+ mile drive, but it is preceded by a surging while stopped in Drive. I've resorted to putting the car in Park at most stoplights since the surging/stalling does not occur in Park.

    I finally inquired at a transmission shop about the cost to swap the torque converter out. The mechanic said the job was too much of a hassle on these cars and said he didn't want to touch it. He said it'd cost at least $1,500 to swap out the TC anywhere I went.

    That sounds a bit steep, no? I used to own an '89 Caprice Classic and I remember paying $1,500 to pull, rebuild the entire transmission and reinstall it. I'm thinking of going to another transmission shop for a second opinion/estimate but first I wanted to know if others agree the torque converter is the likely culprit behind the surging/stalling and if that price seems suspect or reasonable. Any other advice is much appreciated!

  9. #24
    carnut is offline Cadillac Owners Master
    Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
    Join Date
    Feb 2003
    Location
    california
    Age
    67
    Posts
    5,942

    Re: 85 Eldorado - Violent shake at certain level of acceleration

    The torque converter cannt cause engine surging and stalling if the harness is disconnected. I think you have idle speed motor issues. The ISC motor is attached to the driver side of the throttle body as you know and extends/ retracts to maintain an idle within 50 RPM regardless of load on the engine, like parking turning in a parking lot or A/C on etc. Do you have the factory service manual? if not do a search for adjusting ISC and TPS switches here.

  10. #25
    Kiriken is offline Cadillac Owners Member
    Automobile(s): 1985 Eldorado, 2008 STS
    Join Date
    Mar 2009
    Posts
    26
    Thread Starter

    Re: 85 Eldorado - Violent shake at certain level of acceleration

    Sorry I didn't reply in a timely manner, I haven't had much to report. Thank you for the feedback on the torque converter, I don't believe it's related anymore. Because of that I've made a separate thread under the HT4100 subforum (here)

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting