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1971 GTX vibration issue "UPDATED PROBLEM SOLVED" #1358272 12/24/12 01:24 AM 12/24/12 01:24 AM
Joined: Jun 2005 Posts: 287 MI AfterHoursResto OP enthusiast
AfterHoursResto OP enthusiast Joined: Jun 2005 Posts: 287 MI	I just finished a rotisserie restoration on a 1971 GTX 440 auto 8 � with a 323 posi. I am experiencing a on and off type vibration with begins at 40mph - 65mph. It may continue past 65 but that is as fast as I have driven the car since completed. I have placed the trans in N while rolling down the road and the vibration continues even though the engine drops down to an idle. I am running tapered bearings in the rear axels set at .010 .012. The bushing was replaced in the tail shaft of the trans during its overhaul. The drive shaft is brand new and I also tried to but the old shaft in and it did not make a difference. The center section is a 489 case and was rebuilt using the original ring and pinion. Everything is brand new or rebuilt on this car. It was restored to factory specs with no performance modifications. I am stumped. Any input would be appreciated. Thanks Last edited by AfterHoursResto; 02/10/13 10:22 PM. Roman Sobilo

Re: 1971 GTX vibration issue [Re: AfterHoursResto] #1358273 12/24/12 01:27 AM 12/24/12 01:27 AM
Joined: Mar 2008 Posts: 1,913 central P.A. HEMIDOG 70 top fuel
HEMIDOG 70 top fuel Joined: Mar 2008 Posts: 1,913 central P.A.	Tire balance?

Re: 1971 GTX vibration issue [Re: AfterHoursResto] #1358274 12/24/12 01:33 AM 12/24/12 01:33 AM
Joined: Feb 2004 Posts: 7,195 Harrisburg, Pa. screamindriver master
screamindriver master Joined: Feb 2004 Posts: 7,195 Harrisburg, Pa.	Also,you'll need to check the driveline angles and see where you're at...From here it's going to be a process of elimination...Start with the easy stuff...You've already taken the first step...No change in the vibration throwing the car in neutral is the first step...And I'm assuming there's no vibration in park... So it's not an engine balance issue..

Re: 1971 GTX vibration issue [Re: AfterHoursResto] #1358275 12/24/12 02:02 AM 12/24/12 02:02 AM
Joined: Jan 2003 Posts: 18,632 jersey shore F flypaper I hate Texas
flypaper I hate Texas F Joined: Jan 2003 Posts: 18,632 jersey shore	on a 71b body there is a weight that bolts to the floor above the driveshaft. it is there to help driveshaft vibration. is that weight missing? i can get you a pic of it, if you need to see what it looks like.

Re: 1971 GTX vibration issue [Re: AfterHoursResto] #1358276 12/24/12 02:29 AM 12/24/12 02:29 AM
Joined: Apr 2012 Posts: 18,880 - R RSNOMO Moparts Torchbearer
RSNOMO Moparts Torchbearer R Joined: Apr 2012 Posts: 18,880 -	Can you load the suspension on jackstands and run the car???

Re: 1971 GTX vibration issue [Re: RSNOMO] #1358277 12/24/12 02:50 AM 12/24/12 02:50 AM
Joined: Jun 2005 Posts: 287 MI AfterHoursResto OP enthusiast
AfterHoursResto OP enthusiast Joined: Jun 2005 Posts: 287 MI	I have tried two sets of tires. A brand new set of G 60's and the old set of radios the car came with and there was no change. The driveline angle is at 2.5. Thereis no wieght on the tailshaft or floor board. Would like to see a pictures of one! Roman Sobilo

Re: 1971 GTX vibration issue [Re: AfterHoursResto] #1358278 12/24/12 03:58 AM 12/24/12 03:58 AM
Joined: Jul 2004 Posts: 4,732 Watertown, WI MikeyT master
MikeyT master Joined: Jul 2004 Posts: 4,732 Watertown, WI	Could it be a bad u joint? I had the very thing happen last spring and it was a bad u joint. Also I thought pinion angle was suppose to range between 2.5-5.5 nose of diff down. Mike 1969 Dodge Dart Swinger

Re: 1971 GTX vibration issue [Re: flypaper] #1358279 12/24/12 09:50 AM 12/24/12 09:50 AM
Joined: Nov 2008 Posts: 1,491 Lethbridge, AB, Canada dangina pro stock
dangina pro stock Joined: Nov 2008 Posts: 1,491 Lethbridge, AB, Canada	Quote: on a 71b body there is a weight that bolts to the floor above the driveshaft. it is there to help driveshaft vibration. is that weight missing? i can get you a pic of it, if you need to see what it looks like. could you take a pic? I'm in the middle of putting my 71 runner back together and I haven't seen or heard of this weight?

Re: 1971 GTX vibration issue [Re: dangina] #1358280 12/24/12 10:10 AM 12/24/12 10:10 AM
Joined: Aug 2004 Posts: 4,247 Alabama BigMoneyLewis master
BigMoneyLewis master Joined: Aug 2004 Posts: 4,247 Alabama	My first thought would be a wheel out of balance . I know you said you tried two sets of tires , but are you still using the same wheels, if so have they been balanced on a machine ? My second guess would be a driveshaft out of balance . Greg gregward@mchsi.com phone 256-852-0955

Re: 1971 GTX vibration issue [Re: BigMoneyLewis] #1358281 12/24/12 11:34 AM 12/24/12 11:34 AM
Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska	I know you changed shafts but that'd be my guess, shaft or ujoints. How much freeplay does the shaft have into the trans? Want ~3/4" with the common aftermarket flat extension housing seal. I had too much & had a similar vibration that came & went. The correct slightly longer shaft took care of it. Holler how it goes live every 24 hour block of time like it's your last day on earth

Re: 1971 GTX vibration issue [Re: dangina] #1358282 12/24/12 11:36 AM 12/24/12 11:36 AM
Joined: Nov 2003 Posts: 12,494 Western Colorado High Desert moparmarks I Live Here
moparmarks I Live Here Joined: Nov 2003 Posts: 12,494 Western Colorado High Desert	Quote: Quote: on a 71b body there is a weight that bolts to the floor above the driveshaft. it is there to help driveshaft vibration. is that weight missing? i can get you a pic of it, if you need to see what it looks like. could you take a pic? I'm in the middle of putting my 71 runner back together and I haven't seen or heard of this weight? The weight was not used on 71/2 HP cars. Just LP cars. It mounts in the top of the tunnel right at the seam between the rear footwell and the under rear seat pans. Has a plate with 3 studs welded to the floor and the weight mounts to the suds under the pans. I guess I don't have pics but can get some. 72 Satellite Sebring Plus 440, 72 Dart 5.9 4-spd, 68 Valiant, 73 W200, 78 D100 sb, 78 D200, 98 DAKOTA, . Moparmarks Parts & Restorations Desert Mopar Metal Grand Jct. CO 970-261-7039 http://moparmark.com/ motormangj@gmail.com

Re: 1971 GTX vibration issue [Re: moparmarks] #1358283 12/24/12 11:53 AM 12/24/12 11:53 AM
Joined: Jun 2005 Posts: 287 MI AfterHoursResto OP enthusiast
AfterHoursResto OP enthusiast Joined: Jun 2005 Posts: 287 MI	Good suggestions everyone! Thanks. Yes, the tires are mounted on two sets of rims. One set is about a year old and the other are brand new. So I don�t think it is the rims or tires. Both shafts I tried have new u joints. However, I do have more than � sticking out of the tail shaft. Maybe someone swapped drive shafts out before I got my hands on the car. Does anyone have the correct dimensions for a stock factory driveshaft (71 GTX 440 auto 8 �)? Thanks Roman Sobilo

Re: 1971 GTX vibration issue [Re: AfterHoursResto] #1358284 12/24/12 12:52 PM 12/24/12 12:52 PM
Joined: Sep 2006 Posts: 616 TP Exit 7, NJ, USA DANA60 mopar
DANA60 mopar Joined: Sep 2006 Posts: 616 TP Exit 7, NJ, USA	Here's a pic of that weight, not a good one, but all the way at the top of the photo. I don't think it's that. If you have eliminated tires and wheels, how about a bad axle, disc brake (rotor)? Can you put it on a lift and run it? This may show if it's front or rear. You can even test it without tires and wheels. How was it before resto? The 3/4 inch probably is not a problem (keep that in mind till later). 7516691-IMG_3398_1_1_1.JPG (100 downloads)

Re: 1971 GTX vibration issue [Re: DANA60] #1358285 12/24/12 01:02 PM 12/24/12 01:02 PM
Joined: Dec 2004 Posts: 10,552 Rittman Ohio fourgearsavoy I Live Here
fourgearsavoy I Live Here Joined: Dec 2004 Posts: 10,552 Rittman Ohio	Quote: Here's a pic of that weight, not a good one, but all the way at the top of the photo. I don't think it's that. If you have eliminated tires and wheels, how about a bad axle, disc brake (rotor)? Can you put it on a lift and run it? This may show if it's front or rear. You can even test it without tires and wheels. How was it before resto? The 3/4 inch probably is not a problem (keep that in mind till later). I have seen brake drums out of balance causing your exact problem Gus 7516704-savoyburnout.jpg (66 downloads) 64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60

Re: 1971 GTX vibration issue [Re: fourgearsavoy] #1358286 12/24/12 01:20 PM 12/24/12 01:20 PM
Joined: Jun 2005 Posts: 287 MI AfterHoursResto OP enthusiast
AfterHoursResto OP enthusiast Joined: Jun 2005 Posts: 287 MI	I am getting ready to lift the rear, take the tires off, then the drums and see what happens. I will let you guys know. Thanks Roman Sobilo

Re: 1971 GTX vibration issue [Re: AfterHoursResto] #1358287 12/24/12 05:31 PM 12/24/12 05:31 PM
Joined: Dec 2004 Posts: 10,552 Rittman Ohio fourgearsavoy I Live Here
fourgearsavoy I Live Here Joined: Dec 2004 Posts: 10,552 Rittman Ohio	Quote: I am getting ready to lift the rear, take the tires off, then the drums and see what happens. I will let you guys know. Thanks Just remember don't step on the brake pedal with the drums off Gus 7517035-savoyburnout.jpg (58 downloads) 64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60

Re: 1971 GTX vibration issue [Re: fourgearsavoy] #1358288 12/25/12 11:44 AM 12/25/12 11:44 AM
Joined: Sep 2006 Posts: 616 TP Exit 7, NJ, USA DANA60 mopar
DANA60 mopar Joined: Sep 2006 Posts: 616 TP Exit 7, NJ, USA	Yes, and be carefull not to put the car in reverse or park right away after run up. There is no way that the drivetrain will stop on it's own. It's important to make sure the drivshaft stops turning before dropping out of drive. Maybe even turn the car off before that 7517859-IMG_3514_1_1.JPG (62 downloads)

Re: 1971 GTX vibration issue [Re: DANA60] #1358289 12/25/12 12:03 PM 12/25/12 12:03 PM
Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska	Quote: Maybe even turn the car off before that With the drums off that's what I'd do, as you know it can still be turning a bit in neutral. Easy to get fooled since the car ain't moving your brain automatically thinks it's OK to move the selector to a different position. Yes you'd have to have alot more than 3/4" end play for that to be the problem like it was in my case & in diagnosing that problem I noticed that the yoke had to be engaged quite aways in on the output shaft spline till it felt solidly engaged which I thought was strange. I think that was because not all of the inside length of the yoke is splined & that distance varied from yoke to yoke. Holler how things go. live every 24 hour block of time like it's your last day on earth

Re: 1971 GTX vibration issue [Re: RapidRobert] #1358290 12/26/12 06:28 PM 12/26/12 06:28 PM
Joined: Nov 2003 Posts: 12,494 Western Colorado High Desert moparmarks I Live Here
moparmarks I Live Here Joined: Nov 2003 Posts: 12,494 Western Colorado High Desert	71 GTX 440/727/8.75 drive shaft is 50.75" center between joints. Here is the non-HP weight and mounting bracket. I've had/have upwards of 20 71/2B HP cars and none had this weight. I did just partout a 73 Charger 400HP car that has this weight as well as all my 71/3 non-HP cars. 7519451-DCP_0057.JPG (85 downloads) 72 Satellite Sebring Plus 440, 72 Dart 5.9 4-spd, 68 Valiant, 73 W200, 78 D100 sb, 78 D200, 98 DAKOTA, . Moparmarks Parts & Restorations Desert Mopar Metal Grand Jct. CO 970-261-7039 http://moparmark.com/ motormangj@gmail.com

Re: 1971 GTX vibration issue [Re: moparmarks] #1358291 12/26/12 06:29 PM 12/26/12 06:29 PM
Joined: Nov 2003 Posts: 12,494 Western Colorado High Desert moparmarks I Live Here
moparmarks I Live Here Joined: Nov 2003 Posts: 12,494 Western Colorado High Desert	Mounting bracket welded onto the pans. 7519452-DCP_0056.JPG (106 downloads) 72 Satellite Sebring Plus 440, 72 Dart 5.9 4-spd, 68 Valiant, 73 W200, 78 D100 sb, 78 D200, 98 DAKOTA, . Moparmarks Parts & Restorations Desert Mopar Metal Grand Jct. CO 970-261-7039 http://moparmark.com/ motormangj@gmail.com

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