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Adjusting the play in an 8.8 rear end

 
jetbd68
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Posts: 11
Joined: 12/08
Posted: 02/17/11 08:55 PM

I have a 1996 Ford Ranger and there is about a quarter turn of play in the drive shaft.  Is this normal and is there any way to adjust it out if it isn't.  I wrecked the truck last summer when I hit a ditch on the right side with three foot vertical sides doing about 40 mph.  It actually jumped up on the top of the other side of the ditch before coming to rest in the bottom of it.  I was able to dig the truck out with a shovel (always keep a shovel in the back your truck. You never know when you're going to need it).  It knocked the toe out and I had to get the truck realigned.  It also caused a vibration in the rear axle at about 50-60mph.  However, shortly after that a rattle showed up and I have not been able to find it.  It only does it going over bumpy ground and it's worse turning left versus turning right.  It has gotten worse recently, so much so that it does it going over the pedestrian crosswalk stripes painted on the road when I go over them at speed.  It also doesn't help that I live on a dirt road and all the rain we have had down here in Florida has turned it into a potholed mess.  The motor mounts are tight.  Suspension bushings are new.  Transmission is solid mounted to the cross member.  The sychros in the transmission are a little worn, but it and the engine run just fine.  The exhaust is not hitting anything.  Body mounts are tight.  Amazingly, the shocks are still good.  I haven't torn into the rear axle to see if anything has been knocked loose yet.  The vibration seems to have disappeared for the most part.  Could the extra play in the rear axle be causing this rattle?  It's more of a dull thud, so it's not directly hitting the underside of the cab (I checked), but it is loud enough that it sounds like whatever it is , it's going break at any moment.  I have tried to put the video camera under the truck to see what rattled, but it kept cutting off.  I have web camera that I should be able to plug into the camera and put it under the truck, but now that I need it, I can't find it.  Has anybody else had phantom rattle that they could not find?  
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jetbd68
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Posts: 11
Joined: 12/08
Posted: 02/18/11 05:47 PM

The play in the in the driveshaft is actually closer to an eighth of turn.  I also took the inspection cover off the rear end and discovered that the spider were worn, so that's the reason for the excessive play.  Still, could that excessive play cause a rattle that I can feel from floor of the cab?  It feels like whatever it is, it is hitting the underside of the cab,  but it's not.  It feels like the rattle is being sent through the driveline.  I can feel it through gas pedal also.  Has anybody had any experience with rattle like this?  
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Falcon67
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Posted: 02/21/11 09:39 AM

The "play" in the driveshaft will be between the pinion and the ring gear.  You can't really tell how much play there is without holding the pinion still and moving the ring gear with a dial indicator on the teeth.  
Fig11

When you turn the driveshaft, you are picking up that clearance, any slack or slop anywhere in the assembly, from the u-joints to the axle shafts.  

If the driveshaft is out of balance or out of phase, it can vibrate and possibly cause the symptoms you describe.  You can have the shaft checked at a driveline shop.  
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jetbd68
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Posted: 02/21/11 04:54 PM

Thanks.  It doesn't rattle just going down the road, it only does it when I hit a bump.  The u-joints are good.  I think I have narrowed the play down to the spider gears in the differential.  I took the inspection cover off and they were worn.  Moved the driveshaft back and forth and watched the pinion and ring gear.  Most of the play came from the spiders.  The ring and pinion showed little wear.  Could worn axle bearings and/or spider gears cause this rattle and it be transmitted up the driveshaft into the transmission so it sounds like the transmission is falling apart?  
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waynep7122
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Posts: 146
Joined: 10/09
Posted: 02/21/11 09:38 PM

by the way... spider gear sets should be available as a kit from some suppliers....

some kits might come with multiple thickness selective side thrust washers... so you can change the clearance..

also... do you run the same size rear tires???

can you also find a neodymium magnet you can stick to the inside of the housing out of the way... this will catch any metal filing that have gotten suspended in the lube..    you won't believe how clean your lube stays when you do this..

i have used broken PM starter magnets chunks from a friendly rebuilder.. and also some from a blower motor.. just wedged into the corner...

want to know how much metal was in your oil oil.. stick a magnet on a wire... dip it....


seems they call them internal kits...

check this link... there are other suppliers available...

http://nationaldrivetrain.com/shopsite_sc/store/html/page13.html  

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jetbd68
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Posted: 02/22/11 03:54 PM

I have stuck part of an old speaker magnet in it.  I run 31x10.5x15s on the rear, 265/70/15s up front.  Have thought about shimming the spider gears until I can get some new ones.  
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MustangMan
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Posted: 02/23/11 07:41 AM

First rule of NVH diagnosis is if you feel it in the steering column, firewall, or pedals, it is in the front of the vehicle and if you feel it in the seat/floorpan it is coming from the rear of the vehicle.

If you are feeling the rattle in the pedals I would re-examine the front of the truck. You might have a sway bar end link broken or missing bushings, a steering rack bishing bad or other issue. Is this a 4x4 Ranger? you might have front driveline issues.

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jetbd68
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Posted: 02/24/11 07:25 PM

The vibration is coming from the back.  Hopefully I just need new bearings and spider gears in the axle.  Right side hit that ditch pretty hard.  Compacted the right tie rod adjuster.  No snags or slop in the steering box.  Sway bar bushings and end links are good.  It's two wheel drive.  Did not damage the control arms nor the radius arms nor their mounting brackets because this Ranger came with a twin I-beam front suspension which I contend is the strongest suspension system ever put in a vehicle.  As hard as I hit that ditch, if this had been a later model with a double a-arm front suspension there was no way I was getting out of that ditch without a bent control arm.  Just wish I had taken pictures.  There is a grinding noise coming from the brakes.  Thought it was the front, so I put in  new rotors(originals were worn out anyway) and bearings.  Still grinds a little bit.  I have found things that were loose, such as the right side engine bracket to mount nut and one of the right side engine to bracket bolts.  Tightened both, did solve the problem.  I feel it in the gas pedal and in the floor(all over the floor more so towards the front).  I can find no evidence of anything hitting the floor.  It would be louder if it was hitting the floor directly anyway because I removed the carpet.  Since the trip through the ditch, I have raised the body half an inch.  The right fender sliced the the tire when the suspension bottomed out.  The rattle was already there and raising the body seemed to make it more noticeable.  I have even removed the panel on the floor so I could put my hand on the transmission when the rattle was happening and could feel nothing.  I don't feel anything through the shifter handle either.  If I put it in reverse and release the clutch quickly it happens.  I'm nearly at my wits end.  It still drives straight and as I said before all the suspension bushings have been replaced and rechecked for tightness.  
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