Subframe questions 1996 Deville

[rockfangd]

Hi all. I have been chasing a front end clunk in my 1996 Deville for some time now and have had no luck. I have even had shops look at it with no luck.

I have replaced quite a few components with no luck.

I am thinking the noise I am hearing is the subframe shifting. Lately it sounds like the front end is falling out which makes me nervous to drive it.

It clunks bad going over decent bumps and going around curves,

Here is what I have done to try to eliminate the noise and because it needed it

All engine and trans mounts

balljoints

hub assemblies

inner and outer tie rod ends

swaybar links and bushings

strut rod and control arm bushings

Right front strut assembly

There is no play in either side of the front end.

Noise sounds especially worse when bumps are hit on the right side, the noise sounds like it is all over

I have jacked up the body to let the frame hang and have found nothing sagging or rotted.

But I live in upstate NY and our 2 worst enemies are the conditions of the roads and the salt they use on them. I cant even count how many cars I have seen the subframes fall out of, Especially the buick lesabre, I have seen 5 of them alone. All 4 bolts pull out of the unibody just forward of the doors, dead giveaway is the brake lines break due to the twisting and that is how I found 4 out of 5 of them.

Anyway Is there any subframe bushing kits available? if wo without spending a ton of money. I would hate to find out the hard way. Thanks

[Logan]

GM has a few bulletins about sub frame noises. I'll see if I can find them.

The thing about the sub frame bushings...by design...is they can be only tightened so far. So if the rubber starts to rot away...it will get noisy.

[Cadillac Jim]

How about the bearings in the transmission output shafts? Have you checked the CV joints in the half-shafts?

[rockfangd]

I have checked the cv joints and they feel tight and I hear no popping.

I will have to check the output shaft play when I do my tires and will update that question

[Logan]

#53-33-04B: RATTLE / LOOSE LUMBER NOISE FROM FRONT OF VEHICLE - (Nov 1, 1997)

SUBJECT: RATTLE/LOOSE LUMBER NOISE FROM FRONT OF VEHICLE WHEN DRIVING OVER BUMPS (DIAGNOSE/REPAIR PROCEDURE)

MODELS: 1994-97 CADILLAC CONCOURS, DEVILLE, ELDORADO, SEVILLE WITH 4.9L OR 4.6L ENGINE (VINS B, Y, 9 - RPOS L26, LD8, L37)

CONDITION:

SOME OWNERS MAY COMMENT ON A CLUNK, RATTLE, OR LOOSE LUMBER NOISE FROM THE FRONT OF THE VEHICLE WHEN DRIVING OVER SMALL BUMPS AT LOW SPEEDS.

CAUSE:

THIS CONDITION MAY BE DUE TO A NUMBER OF DIFFERENT SOURCES. THESE INCLUDE, BUT ARE NOT LIMITED TO:

- LOOSE STRUT MOUNTING BOLTS, - LOOSE STABILIZER BAR LINK PIVOTS, - COIL SPRING CLASH (1995 DEVILLE ONLY), - NOISY FRONT UPPER STRUT MOUNTS, - NOISY ENGINE MOUNT.

THE USE OF KENT-MOORE TOOL J-39570, CHASSISEAR, IS RECOMMENDED WHEN ATTEMPTING TO IDENTIFY THE SOURCE OF THE RATTLE. IT IS IMPORTANT TO NOTE:

O PROPERLY FUNCTIONING CARS WILL TRANSFER NOISE TO THE CHASSISEAR.

O IF NOT FAMILIAR WITH NOISE FROM A KNOWN GOOD CAR, COMPARISON MUST BE MADE BETWEEN A "GOOD" CAR AND THE CAR TO BE EVALUATED.

CORRECTION:

THE FOLLOWING CORRECTIONS ONLY ADDRESS THE SOURCES LISTED ABOVE. OTHER SOURCES ARE POSSIBLE AND MAY REQUIRE ATTENTION NOT OUTLINED HERE.

1. CHECK THE STRUT MOUNTING BOLT FASTENERS FOR PROPER TORQUE:

- UPPER (TO BODY): 24 NM (18 LB FT) - LOWER (TO KNUCKLE): 170 NM (125 LB FT) - DAMPER SHAFT NUT: 75 NM (55 LB FT)

NOTICE: DO NOT OVER-TORQUE DAMPER SHAFT NUT AS IT COULD DAMAGE THE UPPER STRUT MOUNT.

CHECK TORQUE OF STABILIZER BAR LINK ATTACHMENT POINTS:

- 1994: 65 NM (48 LB FT) - 1995-97: 55 NM (40 LB FT)

NOTICE: DO NOT ALLOW THE BALL STUD TO ROTATE DURING TIGHTENING OF THE NUTS OR THE LINK MAY BE DAMAGED.

2. IF THE TORQUE IS CORRECT IN STEP 1, DISCONNECT STABILIZER BAR LINKS AND DETERMINE IF NOISE IS GONE. IF IT IS, REPLACE THE STABILIZER BAR LINKS.

- 1994 LINK: P/N 3523593 - 1995-97 LINK: P/N 3530406

3. SOME 1995 DEVILLES MAY EXHIBIT A CONDITION KNOWN AS "SPRING CLASH". THIS IS A METALLIC CLUNK NOISE FROM THE FRONT OF THE VEHICLE. THIS SPRING NOISE IS DUE TO LOW SPRING LOAD ALLOWING THE FIRST INNER SPRING COIL TO "CLASH" AGAINST THE SECOND COIL DURING COMPRESSION. TO CORRECT THIS CONDITION, INSTALL COIL SPRING, P/N 22132857 (ONE OR BOTH). THIS IS A REDESIGNED SPRING AND MEETS TRIM HEIGHT SPECIFICATION. THIS SPRING IS FOR VEHICLES BUILT UP TO AND INCLUDING VIN SU266448. VEHICLES BUILT AFTER THIS VIN ALREADY HAVE THE REDESIGNED SPRING INSTALLED.

4. A LOOSE LUMBER NOISE MAY BE HEARD BY DRIVING AT SPEEDS TYPICALLY BETWEEN 10 - 45MPH OVER BOTH SMALLER SHARP BUMPS AND LARGER BUMPS (MORE PREVALENT ON SMALL SHARP BUMPS). REPLACE THE FRONT UPPER STRUT MOUNTS WITH P/N'S 22178707 (FOR ALL 1994-96 MODELS AND 1997 DEVILLE, ELDORADO) AND 22178708 (FOR 1997 CONCOURS, ELDORADO ETC, SEVILLE).

IMPORTANT:

TO DISTINGUISH BETWEEN STEPS 4 AND 5, USE THE CHASSISEAR J 39570 AND ATTACH CLIPS TO THE FRONT ENGINE MOUNT AND UPPER STRUT MOUNT/ SHOCK TOWER AREA. PLEASE NOTE:

O NOISE WILL BE HEARD IF CHASSISEAR IS ATTACHED TO THE STRUT. YOU WILL NEED TO FAMILIARIZE YOURSELF TO A NON-COMPLAINT CAR. NORMAL OPERATING SOUNDS MAY LEAD YOU TO SERVICE A GOOD CAR.

O MORE NOISE WILL BE HEARD IF CHASSISEAR IS ATTACHED TO THE STRUT ROD TOP NUT THAN TO ONE OF THE THREE STRUT MOUNT FASTENERS IN THE STRUT TOWER. YOU WILL HEAR STRUT OPERATING NOISES IN THE NUT, WHILE THE NOISE HEARD IN THE STRUT MOUNT FASTENERS WILL BE MORE QUIET SINCE THE JOB OF THE STRUT MOUNT IS TO DAMPEN. ANY NOISE HEARD FROM THE STRUT ROD IS LIKELY NORMAL; STRUT REPLACEMENT WILL NOT AFFECT THIS NOISE. TO VERIFY, COMPARE TO A KNOWN GOOD CAR.

O ASSURE THAT CHASSISEAR CLIPS ARE SECURELY AFFIXED. ANY MOVEMENT OF THE CLIPS TO THE FASTENING POINT MAY RESULT IN FALSE NOISE BEING GENERATED.

O DO NOT TEST DRIVE THE VEHICLE WITH THE HOOD OPEN TO THE SECONDARY LATCH AS THE HOOD MOVEMENT CAN MAKE FALSE NOISE. LATCH THE HOOD FULLY.

5. IF THE LUMBER NOISE IS PRODUCED AT SPEEDS ONLY BELOW 20MPH WHILE DRIVING OVER A LARGER BUMP, THEN IT MAY BE ENGINE MOUNT RELATED. THIS NOISE SOUNDS AS IF IT IS COMING FROM THE MIDDLE TO UNDER DASH AREA, WHILE STEP 4 SOUNDS AS IF IT IS COMING FROM ABOVE THE DASH. ON VEHICLES EQUIPPED WITH A 4.6L ENGINE, REPLACE THE LEFT ENGINE MOUNT AND THE RIGHT TRANSAXLE MOUNT. ON VEHICLES EQUIPPED WITH A 4.9L ENGINE, REPLACE THE LEFT ENGINE MOUNT ONLY.

- 4.6L LEFT ENGINE MOUNT: P/N 22171688 - 4.6L RIGHT TRANSAXLE MOUNT: P/N 22171682 - 4.9L LEFT ENGINE MOUNT: P/N 22171683

Right now cannot find the one about noisy cradle mounts...

[KHE]

You really need to use some chassis ears to isolate the source of the noise so you do not keep replacing good parts. I am attempting to find someplace that rents them (no progress so far...) as I have a noise on my STS that may be transaxle related.

[rockfangd]

You really need to use some chassis ears to isolate the source of the noise so you do not keep replacing good parts. I am attempting to find someplace that rents them (no progress so far...) as I have a noise on my STS that may be transaxle related.

They are very expensive and I dont know of anyone crazy enough to rent one.

The parts I replaced other than the right front strut complete assembly and the right side balljoint were about the only parts that didnt necessarily need to be replaced

[KHE]

You really need to use some chassis ears to isolate the source of the noise so you do not keep replacing good parts. I am attempting to find someplace that rents them (no progress so far...) as I have a noise on my STS that may be transaxle related.

They are very expensive and I dont know of anyone crazy enough to rent one.

The parts I replaced other than the right front strut complete assembly and the right side balljoint were about the only parts that didnt necessarily need to be replaced

The one that Jim mentioned on Amazon looks like it would do the job for the home mechanic. Replacing good parts can easily add up to more than the cost of the chassis ear plus the cost of the actual bad part that's causing the issue.

[winterset]

I thought I replied to this thread already, but I'll type it again:

Under warranty, I had that noise, and it seemed like it was a known issue (it sounded like a thump at low speeds over a mildly bumpy road, and sometimes it would creak - like a old rockingchair).). Dealer replaced the drivers side upper strut mount. well fast forward 14 years, and it's doing the exact same thing. I have not looked at it yet.

[rockfangd]

Well I have some good news. Tonight I checked out my front end while I replaced my brakes and put my snows on. Everything checked out good til I was torquing the right front wheel and heard a click each time it rocked. I jacked it back up and found the CV joint has play in the inner joints. That is a relief. No play into the trans just in the joint itself.

that would probably explain the little shimmy in the front end that is sometimes worse, sometimes not. I just contributed it to my warped rotors but I guess it wasnt the only problem. So Iwill order a shaft and update the post.

The fact that it is the inner joint is the only reason why I could think that it doesnt click on turns. that kind of threw me off

[rockfangd]

Well guys noise is gone.

While changing the cv joint I found that the balljoint was loose(slightly) in the control arm. The bolts were tight but the balljoint was loose in the center. darn aftermarket parts. I had issues when I installed the balljoint when I did the strut rod bushings. The balljoint was sloppy in the control arm. I called raybestos and was told that the bolts would tighten it up. Wrong. What I did tonight was slide 3 washers between the balljoint and the upper part of the arm section. Next year I will likely replace the balljoint again with AC delco part. I always use ACdelco but when I did the balljoint it was the only thing I could get at the time.

So anyway New CV joint and now tight balljoint and voila no more noise. I knew the noise was more than just the cv joint.

One thing I did notice though which I dont think is normal was that when I had the cv joint out of the trans that the shaft in the trans feels sloppy, moves around a little bit and pulls in and out slightly. I am thinking that is the cause of my high speed shimmy that I have had for a long time. once new shaft was installed nothing moved, Note I have never leaked any transmission fluid.

Thanks to all for all of the help