Time to rebuild my differential

[TurboStreetCar]

Well, i had to call my tuning session on the dyno early when my car was letting out a horrid howl under even the slightest throttle. Thought it was the TH350, put it on jackstands and its definitely the differential. Pissed cause i didnt get to tune anything over 20psi. Still made 515hp to the wheels though.

Where does everyone source there parts for the rear? Going to change bearings, seals and likely the ring and pinion and clutches for piece of mind.

Ill post up pics of everything later tonight after i tear it down.

-Dan

 

[AbsoluteSpeed]

Driftmotion sells a rebuild kit http://www.driftmotion.com/product-p/dm3005.htm
While your at it, you can upgrade to a more aggressive clutch pack. Looks like it would suit your setup http://www.weirperformance.com/maxgriplsdkits.html

Lastly, I remember there is a piece to replace the crush sleeve (like a solid spacer or something). But I can't remember what that was all about, maybe someone else can chime in on the subject.
Edit: Found it, http://www.weirperformance.com/solidpinionspacerkits.html

 

[TurboStreetCar]

Yes a crush sleeve eliminator is definatly going in. Driftmotion is cheaper before shipping then my dealer $339 to $380.

I got it out and i pulled the cover off, There was still around 2 quarts of fluid in it so thats a good sign. I dont see anything obvious other then i can spin the differential pretty easily by hand by both the pinion and the axle stubs. I noticed that if i spun the diff by the axle stubs in the forward (as if it was in the car) direction it spins quiet but if i spin it in the reverse direction it makes some noise.

I put a drill on the pinion nut and i notice that if i spin it at a constant speed it doesnt make much noise, but if i throttle the drill up and down, when i accelerate the pinion in the forward direction i get noise.

Im not sure what i should do at this point. Should i re use the gears? How can i tell if there worn out or damaged? There are no missing teeth and i dont see any unusual wear pattern or gouges.

I want to get a plan of attack asap on this thing so i can get it back in and finish tuning.

Thanks,
Dan

 

[MarkIII4Me]

Did you see any metal on the magnetic drain plug?
Just got done rebuilding mine. Scored the parts from RockAuto (Timken and National) and saved like 2/3rds of what Toyota parts cost. If your bearings are making noise then they need to be replaced. My outer pinion bearing was jingling like bells. My gears were also worn to razor blades on the inner teeth. I had no luck scoring a set of good used or new 3.73 gears. I put it back together with the old ones and I could not get the preload right on the pinion gear. It's about 20% too lose even with a custom shim I added, and if I went any thicker I would lose the gear placement. When I got in there I noticed it had some National bearings in it already, so it's not a virigin diff. Not sure what's wrong with the thing as the housing may even be worn. It performs much better after rebuild and is quiet under throttle, but howls like crazy when I take my foot off of the gas. I'm still in the market to find a good 3.73 that I can throw my LSD into.

Btw, good luck getting the old race off and new race onto the pinion gear shaft. Royal PITA!

 

[TurboStreetCar]

Yea drain plugs got a bunch of metal on it. But the diff has over 180k on it and it hasn't been touched in the last ten years I owned the car. Prolly never was.

I see Yukon makes gears for our cars and I think they make 3.73 also. I want to stay 3.73. I gotta get it further apart to see whats up.

-Dan

 

[MarkIII4Me]

Not going to find any new gears for our ratio, aftermarket or not. All that's out there now I for the 8" truck rears which start at 4.10 and go up from there. Believe me, I've looked. Weir Performance doesn't have any used ones in stock at the moment, but if you ask Spence nicely I'm sure he'll have no problem locating some good ones for you. I was going to go that route until I found that my diff's housing is most likely trashed. I really need to find a healthy donor dammit!!!

 

[TurboStreetCar]

Heres the Yukon gear set that i found in 3.73

http://www.yukongear.com/PartsList...."+V6+Rear&CatID=35&CatName=Ring+&+Pinion+Sets

There on summit for just under 300 for the set.

Heres a pic of the Ring gear.

 

[Piratetip]

Good to see more people tearing into these differentials.

Ohh that looks like it got toasty.
Lost a bunch of the face hardening on the drive side tooth.

 

[TurboStreetCar]

How can you tell? TEACH ME!!!! :biglaugh:

-Dan

 

[TurboStreetCar]

Heres a Video of the noise it makes when turned by hand

[video=youtube;_GUsbBHF9Gg]https://www.youtube.com/watch?v=_GUsbBHF9Gg[/video]

EDIT: the red on the inside/bottom of the tooth is fluid not the metal discoloring.

 

[Piratetip]

How can I tell?

1. Heavy noise loaded drive side
2. Wear pattern scattered all over the face of the drive side
3. Darkened heavily loaded/heated areas deep on the face, also scattered all across
4. Your crush sleeve is all but destroyed/no preload on the pinion bearings allowing the pinion to move around way too much
5. The drive side is no longer shiny/looks as though sandpaper was taken to it
6. None of the bearings are under any preload whatsoever.

How much worse does the pinon look?
How much slop can you feel in the ring & pinion backlash
How sloppy is the pinion flange radially?

Edit:
And the video shows unloaded drive noise as well.
Basically everything inside that differential is trashed.
All bearings, ring & pinion.

 

[Piratetip]

I have a built 4.30 LSD for sale if you haven't noticed
Going to cost about as much to rebuild the one you have.

 

[TurboStreetCar]

You have PM.

Really looking to stay 3.73 because of my TH350. Any advice on what i should do?

 

[Piratetip]

Find a decent donor 3.73 on here & rebuild it.
Going to cost less than trying to source a new ring and pinion + all bearings & related parts.

 

[TurboStreetCar]

I kind of feel that if im going to spend the money id want everything new anyway. Im gonna do some research on gear sets.

Then again going solid axle is looking kinda nice right about now. I do have a ford 8.8 sitting around waiting to be used.....

 

[Piratetip]

Best of luck.

 

[TurboStreetCar]

Thanks, haha. i got some decisions to make. The 8.8 is sounds nice though. Ill be the next Slow66 haha.