Jump to content

rear roar noise still after rear bearing replacement.


freeman

Recommended Posts

my 85 nissan 720 kc 5 sp. 250k       las vegas    anyone ever had this happen?  and the fix it took. id appreciate the info.

grouling roaring noise seems to come from the bed area.. from the left rear wheel..like a bad L r bearing.

It doesnt happen until its good n hot.. all oil n fluids fully hot..now summertime 100+ temps and 10 miles of driving it.  

 especially after 10 mile highway trip at 65-70 mph.  then.exit.. on left turns the roaring will start til straightening out and making it to 3rd gear...or thru 4th gear when floored. when really normal hot..is also noisey just taking off straight and gassing it a bit more than usual.

 

i just got it back from a shop that replaced both rear wheels' bearings. cost me $530.   i drive 10 miles..and no change so its not the rear wheel bearings? i did get the old parts and got 2 bearings 2 races and 2 seals. 

 

previous work done to MAYBE rule out cause. work done the past 6 months-

-new front calipers brakes and rotors

-all new ujoints. 3 total.

-new trans and differential fluid..i recently double checked..is full ..clean.

 

-after a week of the grouling(before having bearings replaced) i decide to check the neutral switch..doesnt work because i checked and bump started it in 1st gear a couple times leaped forward.. BUT...the 2nd time something stuck= pushing in the clutch when motor was running wouldnt allow me to put in any gear..it would of grind way too hard   so i replaced the slave cyl and fluid and still no good..for a possible fix i decided to start it in 1st gear and pushed the clutch in and out and finally it fixed itself..and is working like its old self. COULD GROULING AT HOT OPERATING TEMP AND LEFT TURNS BE THE TRANSMISSION ?  AFTER THAT THING GOT STUCK AND UNSTUCK?.

 

im guessing its the differential? 

 

Thank you.

 

  • Like 1
Link to comment
  • Replies 23
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Or the ring & pinion are shot.

What did the old fluids look like when you changed them ?

 

What did the old bearings look like ?

 

Maybe the drive shaft, but I kind of doubt it.

Noise would be from them not timing the two halves correctly, but would not only happen after getting hot.

 

I suggest finding a new mechanic, or learning to do some of this yourself.

$500 would have bought a lot of tools, and a service manual.

  • Like 4
Link to comment

Thanks. its back in shop. Must be ring pinion now..

 

Tires r like new.. Alignment on track.

Forgot to add carrier bearing is good..its the 2nd or 3rd I've replaced.

 

I almost attempted the bearings.. would of been a racket..then onto the ring pinion. Hellofa lotawork im no mechanic but do ok hating it...my flooring work is easy and pays good so Would of been sweet to just have a mechanic fix it..but hell no..big shop is on the hook says will take care of it. Seems all rear axle problems/noises sound the same.

  • Like 1
Link to comment

$490 to replace two $20 bearings? Drain the diff oil and look at it. If the diff is the problem it will show in the oil. How would this mechanic not rule out the differential first?

 

 

To rule out the tires swap the backs to the fonts.

 

Anything rubbing on left turns?

  • Like 1
Link to comment

I take that you had the 2 axle bearings replaced.  I would guess that it is pinion bearing or the 2 carrier bearings or the ring and pinion, or a combination of these.  Have the third member rebuilt or get one from a wrecking yard.  Be sure you stay with the same ratio.

Link to comment

hey yall i got the diagnosis. that metal is in the differential oil it needs rebuilding...its $3450.     we settled for an $89 diagnosis fee and i was returned $430.

i didnt know to drain the oil and took it to a shop. they replaced the axle bearings for nothing.

 

Ive overloaded this truck sooo many times in the last 5 years with carpet, pad and pallets of flooring is the reason im sure. just driving empty i bet would last forever.

 

im all in..FSM..research and doing all the work to it myself now on like i said 3 years ago. hate learning but easier thereafter.

it has  3.6 gears and 225 tires in back for good 75-80 mph highway cruising.

 

why do i need the same ratio?  just if i replace the center parts..ring and pinion..the gears in there?  ive never looked into it i dont know it AT ALL yet..i need a FSM.

guess if i can just get a whole other axle then ratio doesnt matter right.  maybe have to shift  through the gears faster with 4 something gears. 

 

hope to get an axle cheap.. that would be easier than anything else for me.  im some kinda dummy i reject learning unless provoked..

Thanks yall. 

  • Like 1
Link to comment

Pull the axles back out, pull the third member out of the housing.  Clean housing thoroughly with solvent.  Go to a wrecking yard and buy a used third member from a 720 with the same ratio or a complete rear and swap it out.

 

Buy a trailer to haul your carpet and tools on.

 

After buying the trailer and do the repairs on your truck you will probably have enough left out of the $3450 to buy a 12 pack!  LOL

Link to comment

HAHA YES MY WHEELS  HAVE NEW BEARINGS ILL GO FOR THE 3RD MEMBER REPLACEMENT.  

  ILL FIND ANOTHER TRUCK WITH THE SAME FIREWALL TAG GEARS LIKE MINE. AND LOOK FOR ANY NUMBERS ON THE AXLES TO COMPARE THEIR THE SAME...  PICK UP GL5 AND SOLVENT.       OR A COMPLETE SWAP LAST RESORT.

BACK IN THE RIGHT MINDSET I CAN DO ANYTHING.  IM LOOKING FORWARD TO IT..  THANK YOU.

  • Like 1
Link to comment

Can someone tell me how to fix a ring and pinion  can they be bought and simply replaced?

after headache passes ill do research ..i love the truck but hate research and repairs.

Thanks,

Don't build a new differential. Buy a used one from a wrecking yard or a fellow Ratsuner.

 

A new diff (having one built) will cost you about $600-$700 just for the diff, and then the cost to remove it and replace it in the axle. A used diff will save you hundreds of dollars and will only take a couple  hours to replace.

  • Like 2
Link to comment

At the junkyard now. Located one..with same 37 gears..same 1985 5 sp.

So I can just remove the wheels..slide the axles out then remove the 3rd member..and replace mine?

This replacement oil looks good no metal and moves around fine.

 

When I remove the cover bolts I can just lift it out and put in mine?

Will there be pieces to worry about falling off it..to put back on before I place it in my diff? Thanks.

  • Like 1
Link to comment

Now my clutch went out. i have to start it in 1st and time the stop lights just right.

i checked  new slave and its working fine. something popped when i depressed the  clutch and its not fixing itself this time. luckily i was still in neutral.

 

any suggestions on where to buy  or brand  pressure plate ..throw out bearing etc..appreciated.

 

got the 3rd member home.  just one part ..no pieces to woory about. man its easy to replace..so glad.

 

today replacing the 3rd member ..tomorrow looks like im dropping the trans and replacing the clutch..  hope its as strait forward as 3rd member replacement.

any suggestions appreciated.

  • Like 1
Link to comment

One thing that I don't think that anyone's mentioned yet, is your new bearings were swimming in the gritty gear oil.  Since you'll have the axles out anyway, flush them good with clean solvent and blow them out good.  Hand check for free movement; any hesitation or binding flush again.  Hopefully they didn't run long enough to get any pitting.

  • Like 1
Link to comment

I doubt your actual clutch blew. If something "popped" as you say, it's more likely that one of the four parts to the hydraulic part of your clutch system died.

 

The four parts are the clutch master cylinder, clutch slave cylinder, clutch slave hose and hard line connecting them all. Start your search with the hydraulic system before you pull the trans. It will be easy to spot the fluid mess. For the clutch master, the mess may be under the dash inside the cab, not in the engine bay.

  • Like 2
Link to comment

Heres an update.

I replaced the diff yesterday and it has the same grinding roaring noise.

So  replacing the rear bearings and diff... didnt fix the noise i originally posted about.

 

old bearings look ok.  old diff looks ok with no shavings i see after cleaning the diff housing and fluid change.

(but mechanic shop probably drained diff fluid previously before their diff rebuilt quote).

 

...checked master and new slave engaging.   theres no oil leaks and  working properly.

 

suspecting the noise coming from the 5 spd?  or front Wheel bearings but theyre 6 months old and checked both sides with grease caps off..theirs no slack.       or wheel wobble.   

carrier bearing looks great and centered..holding shaft tight.  ujoints look new and about 6 mos old.

both driveshafts are tight no wobble.

 

 

 ill get in the bed and have someone do left turns so maybe i can pinpoint the noise location...damn sure loud enough.   

  • Like 1
Link to comment

You need to pull the axles and the third member.  Flush the axle bearings and the third member well with solvent.. Then pack the axle bearings with grease and set aside with the clean third member.  You also have to clean and flush the axle housing.  After flushing the housing out until no more dirt or metal comes out.  Then you are ready for reassembly.  I use diesel fuel with a siphon gun hooked up to my air compressor to spray the diesel fuel through the axle openings into the third member area.  I take a third member gasket and make a piece of cardboard to cover the third member opening.  I use a large drain pan to catch all the dirty diesel fuel that comes out of the drain hole in the rear end housing.  After you get the axle housings cleaned remove the cardboard and clean the inside of the third member area with clean diesel fuel and a parts cleaning brush..  Be sure to wear proper safety gear as there is a possibility of the diesel fuel splashing back.  You cannot install a good third member in a dirty housing and expect it not to make noise.

 

If you want to pull the axle housing out you can find a shop that can hot tank the axle housing and clean it for you.  I used to have NAPA's machine shop clean them for me years ago.  Just be sure that the housing is clean.

 

To check the third member for wear you check how much play there is in the ring and pinion by turning the pinion yoke where the driveline attaches.  Move the pinion back and forth to see how much slop is in the ring and pinion.  The less slop the better.

 

If the rear end you purchased is noisy take it back to where you got it  and get another one or your money back.

 

It might be best for you to buy the whole rear end if you do not want to clean everything be fore assembly.  This means you have to disconnect the e-brake cables and the Hydraulic brake line.

Link to comment
  • 3 weeks later...

FIXED IT...somehow.   After the throw out bearing went...i ordered all new clutch stuff.. removed the 5 speed and did clutch job..put trans back in and now that low tone aweful plenty loud grinding noise has disappeared.    for 2 weeks now so im starting to run it harder like before.

Next is balancing the driveshaft as i washed the alignment marks away and have vibes that wasnt there before.

 I like the balance trick on utube where a guy uses a clear plastic cup with some water in it....which is attatched to the diff.    looks like balanced causes pretty smooth water level.

anyone have an easier way lmk thanks.  for 2wd KC 2 piece shaft.

Should the weight on each shaft be in alignment to the other or should they be 180 off?      ive looked online at pics of new shafts and of course theyre missing or out of focus. or tiny ass useless pics.

Link to comment

shaking_head_breaking_bad.gif

 

So after all the wheel bearing replacement and talk of rebuilding the differential the problem was at the front of the truck?????

 

Why are you thinking of balancing the driveshaft?????? Unless it was dented or otherwise damaged it won't go out of balance. You have a two piece driveshaft? Take a good look at the carrier bearing at the back of the front drive shaft. If the rubber isolater is rotted away, this is the problem. Check the U joints. A worn joint will destabilize the drive shaft and vibrate.

Link to comment

Noise coming from possibly the middle to the rear   but not the front.  it was getting worse and now its gone.

but something may go out with an explosion who knows     it doesnt make sense..

but ive replaced a few carrier bearings its 95% good checking it 5-6 times wishing it was a simple fix.they can not make that kind of noise..ujoints master cyl slave cyl or fluids cannot make that kind of grinding noise. 

 

once i replaced the clutch -( only the plate,,cover..throw out and sleeve..both clips)

 and lost the driveshaft mark.    i decided to turn the front short driveshaft 180 just to see if it could possibly roll any smoother.   doesnt roll smoother its worse.  pretty sure the front ds weight needs to be aligned with the rear ds weight down the line as its always been before.  instead of just putting the front ds back so weights are aligned again and    "call it good"........ ive got to do the whole testing thing to be sure its as good as it can be....because if i have to screw with it im going to know its as good as it can get.   its just going to take a hellof alot of time..in this insane summer heat. 

  • Like 1
Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.