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727 noise problem??? #1274883 07/27/12 12:17 PM 07/27/12 12:17 PM
Joined: Jun 2005 Posts: 310 western Ky CraigS OP enthusiast
CraigS OP enthusiast Joined: Jun 2005 Posts: 310 western Ky	Hey everyone, I have a situation with my racecar,I have a LOUD noise on deceleration only, in my 727??? maybe.I say maybe cause the trans guy I had highly recomended tells me there is nothing in the trans that can make this noise.Its a loud gear roar type sound, at the end of the track after i let off the gas,its so loud its heard over the open headers.It seems to me it always made this noise ,just 100 decibels less before.I t works great down the track ,shifts good and tight,but at the end ,when i am decelerating after the pass it makes the noise.After it slows down to a coast ,it stops makin the noise,but even as i am coasting thrue the pits with the engine off,in nuetral,if i slow down with the brakes it makes the noise again.The trans guy says its my rearend.The rearend is a $2500 moser dana60 2years old with only 200? passes on it,and i cant believe it could be that!!!Its a pro gear 4.56 ,spool,35 spline axles,aluminum "preload on the caps" rear cover.top of the line .So my question is ,What do you fellows think? I know its impossible to diagnose a problem over the internet,but any ideas???

Re: 727 noise problem??? [Re: CraigS] #1274884 07/27/12 12:34 PM 07/27/12 12:34 PM
Joined: Oct 2005 Posts: 164 Savannah, GA mopar400 member
mopar400 member Joined: Oct 2005 Posts: 164 Savannah, GA	Quote: Hey everyone, I have a situation with my racecar,I have a LOUD noise on deceleration only, in my 727??? maybe.I say maybe cause the trans guy I had highly recomended tells me there is nothing in the trans that can make this noise.Its a loud gear roar type sound, at the end of the track after i let off the gas,its so loud its heard over the open headers.It seems to me it always made this noise ,just 100 decibels less before.I t works great down the track ,shifts good and tight,but at the end ,when i am decelerating after the pass it makes the noise.After it slows down to a coast ,it stops makin the noise,but even as i am coasting thrue the pits with the engine off,in nuetral,if i slow down with the brakes it makes the noise again.The trans guy says its my rearend.The rearend is a $2500 moser dana60 2years old with only 200? passes on it,and i cant believe it could be that!!!Its a pro gear 4.56 ,spool,35 spline axles,aluminum "preload on the caps" rear cover.top of the line .So my question is ,What do you fellows think? I know its impossible to diagnose a problem over the internet,but any ideas??? A pinion bearing in the rear end could cause that noise. If its the outer bearing it would be louder when letting off the gas. The way the gears are cut the force on acceleration tries to push the pinion toward the front of the car and loads the inner bearing. Letting off the gas loads the outer bearing because the pinion is trying to get sucked into the diff. housing. I've also had a roar/ vibration when letting off the gas in the 1/4 mile because i had too much pinion angle. The car was smooth under load but when the front of the pinion dropped on decel. it would vibrate/ roar. Kevin Also I would check to make sure the pinion nut has not come loose Last edited by mopar400; 07/27/12 12:35 PM. 1965 Fury II 1970 Challenger 440, 509 cam, 11:1 w/ 452 iron heads, 6.99 1/8, 11.29@ 120mph 1/4 (1999 Magnolia Drag strip track champion) 1992 Jeep XJ Crawler

Re: 727 noise problem??? [Re: mopar400] #1274885 07/27/12 12:40 PM 07/27/12 12:40 PM
Joined: Jun 2005 Posts: 310 western Ky CraigS OP enthusiast
CraigS OP enthusiast Joined: Jun 2005 Posts: 310 western Ky	Ok,The nut is tight,I am draining the fluid out of the rear right now,to get the cover off,what do i need to look for?there does not seem to be any metal chips/shavings in the oil.I did change the gear oil over the winter,and changed to synthetic.Yhe noise was not there last year at the end of the season....then on the first pass this year its there...how can it happen so fast???

Re: 727 noise problem??? [Re: CraigS] #1274886 07/27/12 12:43 PM 07/27/12 12:43 PM
Joined: Jun 2005 Posts: 310 western Ky CraigS OP enthusiast
CraigS OP enthusiast Joined: Jun 2005 Posts: 310 western Ky	Oh and the pinion angle deal ....i do have it nosed down at rest if this is the cause is there any thing to worry about??? I can see where it could really change the angle on decel,but will it hurt anything?

Re: 727 noise problem??? [Re: CraigS] #1274887 07/27/12 12:46 PM 07/27/12 12:46 PM
Joined: Oct 2005 Posts: 164 Savannah, GA mopar400 member
mopar400 member Joined: Oct 2005 Posts: 164 Savannah, GA	Quote: Ok,The nut is tight,I am draining the fluid out of the rear right now,to get the cover off,what do i need to look for?there does not seem to be any metal chips/shavings in the oil.I did change the gear oil over the winter,and changed to synthetic.Yhe noise was not there last year at the end of the season....then on the first pass this year its there...how can it happen so fast??? Does it make the noise only with the brakes applied or both letting off the gas and w/ brakes applied? A bad bearing should have some shining metal flakes in the housing. Taking the yoke off and pulling the front bearing would be the only way to really inspect for roller damage. 1965 Fury II 1970 Challenger 440, 509 cam, 11:1 w/ 452 iron heads, 6.99 1/8, 11.29@ 120mph 1/4 (1999 Magnolia Drag strip track champion) 1992 Jeep XJ Crawler

Re: 727 noise problem??? [Re: CraigS] #1274888 07/27/12 12:49 PM 07/27/12 12:49 PM
Joined: Oct 2005 Posts: 164 Savannah, GA mopar400 member
mopar400 member Joined: Oct 2005 Posts: 164 Savannah, GA	Quote: Oh and the pinion angle deal ....i do have it nosed down at rest if this is the cause is there any thing to worry about??? I can see where it could really change the angle on decel,but will it hurt anything? My pinion angle was very excessive (don't remember measurement). I kept going rounds that day and ended up cracking the tail housing Young dumb mistake and lesson learn.... 1965 Fury II 1970 Challenger 440, 509 cam, 11:1 w/ 452 iron heads, 6.99 1/8, 11.29@ 120mph 1/4 (1999 Magnolia Drag strip track champion) 1992 Jeep XJ Crawler

Re: 727 noise problem??? [Re: mopar400] #1274889 07/27/12 12:56 PM 07/27/12 12:56 PM
Joined: Jun 2005 Posts: 310 western Ky CraigS OP enthusiast
CraigS OP enthusiast Joined: Jun 2005 Posts: 310 western Ky	i think my angle at rest is 3-4 degrees i cant remember .but its close to that.man i hate to tear into this high dollar rearend,i got it cause it kept breakin 8 3/4s over and over.Now i have to work on this one too??? i thought that 2500 bought me less trouble???

Re: 727 noise problem??? [Re: mopar400] #1274890 07/27/12 12:58 PM 07/27/12 12:58 PM
Joined: Jun 2005 Posts: 310 western Ky CraigS OP enthusiast
CraigS OP enthusiast Joined: Jun 2005 Posts: 310 western Ky	It only makes the noise on deceleration,wether by engine braking ,or with the brakes.

Re: 727 noise problem??? [Re: CraigS] #1274891 07/28/12 05:43 PM 07/28/12 05:43 PM
Joined: Jun 2005 Posts: 310 western Ky CraigS OP enthusiast
CraigS OP enthusiast Joined: Jun 2005 Posts: 310 western Ky	i have checked the rearend out and there is not a thing wrong there..... anybody out there have any ideas or experiences with a transmission making a loud noise on deceleration???????

Re: 727 noise problem??? [Re: CraigS] #1274892 07/28/12 07:27 PM 07/28/12 07:27 PM
Joined: Oct 2003 Posts: 7,506 Az Crizila master
Crizila master Joined: Oct 2003 Posts: 7,506 Az	Still believe it's in the diff. Did you filter the drained oil to look for stuff? How does the gear pattern look? Lots of pinion angle could do it also, but you would get a rumble / vibration with the noise. Are you coasting down in gear or neutral? Fastest 300

Re: 727 noise problem??? [Re: Crizila] #1274893 07/28/12 07:55 PM 07/28/12 07:55 PM
Joined: Aug 2003 Posts: 3,101 cincinnati ohio M mcat4321 master
mcat4321 master M Joined: Aug 2003 Posts: 3,101 cincinnati ohio	bad leaf springs causing the pinion to drop too much on decel.

Re: 727 noise problem??? [Re: CraigS] #1274894 08/14/12 02:15 PM 08/14/12 02:15 PM
Joined: Oct 2005 Posts: 164 Savannah, GA mopar400 member
mopar400 member Joined: Oct 2005 Posts: 164 Savannah, GA	Quote: i have checked the rearend out and there is not a thing wrong there..... anybody out there have any ideas or experiences with a transmission making a loud noise on deceleration??????? Did you ever figure this out? 1965 Fury II 1970 Challenger 440, 509 cam, 11:1 w/ 452 iron heads, 6.99 1/8, 11.29@ 120mph 1/4 (1999 Magnolia Drag strip track champion) 1992 Jeep XJ Crawler

Re: 727 noise problem??? [Re: mopar400] #1274895 08/14/12 06:49 PM 08/14/12 06:49 PM
Joined: Oct 2008 Posts: 411 Harleysville, PA USA T Tommy D mopar
Tommy D mopar T Joined: Oct 2008 Posts: 411 Harleysville, PA USA	I'm very interested in this. I am having the exact same problem with the 727 (pushbutton) with slip in yolk. I'm wondering if the post above about old leaf springs could be both of our problems. Are your leaf springs aged? We've been through a number of tail shafts trying to fix this problem. Thought we had it nailed and ran off and on for six years or so. Now the tail shaft and U-joint problems. Guess I'll stay tuned. Good luck working it out. TD

Re: 727 noise problem??? [Re: Tommy D] #1274896 08/14/12 08:12 PM 08/14/12 08:12 PM
Joined: May 2007 Posts: 1,443 Maryland D Dads426 pro stock
Dads426 pro stock D Joined: May 2007 Posts: 1,443 Maryland	We had a similar problem last weekend, but it involved vibration too. Pinion nut backed off. You say you checked it, but as a locknut it could be hard to turn. You really need to lock the yoke to check the torque and there should be some preload when you try to spin the yoke. Also, a seized u-joint will make a roaring sound 2012 422 Allstars NSS Champion 2013 422 Allstars NSS Champion 2014 422 Allstars NSS Champion

Re: 727 noise problem??? [Re: Dads426] #1274897 08/23/12 09:53 PM 08/23/12 09:53 PM
Joined: Jun 2005 Posts: 310 western Ky CraigS OP enthusiast
CraigS OP enthusiast Joined: Jun 2005 Posts: 310 western Ky	Sorry fellas but after a couple days of no hits ,i stopped paying attention to this thread,I still have not taken it back to the track .I have to put in a new set of lifters 1st,but thats another story.The rear end is so smooth to turn by hand,it just cant be the problem.I did hold the yoke when i tested the tightness of the nut,its good.The u-joints felt good no play but were a little stiff.They dont have a grease fitting,but i put some more grease in the caps before reinstalling them.The noise really sounds like a gear or bushing/bearing rather than a vibration.....i am gonna run it up and down the road after lifter install and get my partner to listen....maybe we can find out what or where.And the age of the springs,they are at least 15 years old ,mopar superstock springs for 2800 lb car ,i think 002, and003"s????They seem fine the car still sits up high and they work great ,no wheelhop or any other traction problems.I will get back on here when i find something out,but life is gettin in the way right now,I am really broke.

Re: 727 noise problem??? [Re: CraigS] #1274898 08/23/12 10:08 PM 08/23/12 10:08 PM
Joined: Oct 2010 Posts: 2,408 Ambridge, Pa. R rickraw top fuel
rickraw top fuel R Joined: Oct 2010 Posts: 2,408 Ambridge, Pa.	this would be alot of work, have u considered trying another rearend? just to see if ur new one has issues.

Re: 727 noise problem??? [Re: CraigS] #1274899 08/23/12 11:18 PM 08/23/12 11:18 PM
Joined: Mar 2008 Posts: 5,746 Ontario, Canada Dodgem master
Dodgem master Joined: Mar 2008 Posts: 5,746 Ontario, Canada	make sure you lube the slip joint going into the back of the transmission! I chased a while in my tranny once and that was it! Just something to look at.

Re: 727 noise problem??? [Re: Dodgem] #1274900 08/24/12 11:49 AM 08/24/12 11:49 AM
Joined: Mar 2007 Posts: 12,013 Finally a HUSKER again Moparnut426 I Live Here
Moparnut426 I Live Here Joined: Mar 2007 Posts: 12,013 Finally a HUSKER again	Its honestly very hard to tell just by looking at the oil if the pinion and side bearings are junk, You almost have to pull the pinion and carrier out to check for pitted rollers, and somethine the rollers look fine, but the race is flaked really badly. Ive gotten pretty good at cleaning and inspecting the bearings, I use a pen light, and an o ring pick to lift the rollers and cage to look at the race under the rollers. A lot of the time the rollers will be so pitted and gnarley that you can tell right away. What is the rearend? an 8.75 or Dana?

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