Thread: Diff Replacement--ON CAR--End Play Check & Ordering Parts--Few Qs

back for more help.

I've been referring to trannyman's how-to, but its for off car. Made it to the part where he does not have pics for on car, and I could use some more direction.

I tried to insert diff into internal ring gear for about 20 min, & couldn't get gears 'lined up'--seemed impossible. decided, what the hell, put car in Neutral and had planetary gears in internal ring gear in about 1 min. but the output was no where to be seen....

I noted I could rotate diff carrier and planetary gears turned in internal ring gear. I noticed I could spin pinion gears, then if I wiggled it just right the diff slid in slightly more, to where outer face of plantary gears where nearly flush w/ outer face of internal ring gear, and I could no longer spin pinion gears.

I Think that means the outer output shaft teeth are set in diff and compression ring is doing its job. & this is the part where trannyman says a 2nd person needs to hold the driver's side cv axle tightly while you tap in diff while keeping gears lined up...

I thought when I got to this point it would make sense, but I seem to be wrong every other step. S0,

1) should I remove diff and start process over, since trannyman says hold driver axle AND tap diff in?

2) what gear should I be working in?

3) when I get the calvery here to hold the drivers cv axle, does it matter if hub nut, or even wheel, is still on drivers axle?

4) before i start hitting my new diff, how do I KNOW gears are all lined up?

I appreciate all the help.

Thanks Bill, but I'm still unclear on couple of things. I am working alone, its kind of a hassle for me to call in favor to climb under car...

At this point, diff is set in internal ring gear, but final drive shaft is NOT seated, & drviers wheel/axle nut/axle are still on.

Bill, you started by saying you typically have drivers cv axle out, then in next paragraph you say wiggle drivers cv axle & give it a thrust to set compression ring?

I am confident enough that diff is in internal ring gear properly to try to put trans ext cover on. If cover fits on flush and tight, can I THEN set the final drive shaft/compression ring by applying force inward on the drivers cv axle? If yes, then does this work if drivers wheel is still on, or should I remove drivers wheel and/or axle nut? Seems like you could just loosen axle nut & give it a good tap w/ a hammer, the way you do to free it from hub splines--that gives axle an inch or two of play horizontally? But I don't know if that horizontal movement/force is transferrred all the way from drivers cv axle thru to diff final drive shaft (w/o hurting anything)?

Or am I just off base?

And I am worried, so I have to ask, does it matter what gear trans is in when wiggling pushing on these parts?

Again, this is truely appreciated.

Got the diff and final drive shaft installed and aligned properly. Thanks! details after putting it together , filling fluids, & successful test drive

just finished test drive. all seems good. proper follow up after I catch up on some rest.

THANKS. again, could not have done it w/o you.

Its been a while, but I did want to follow up. Maybe help the next guy out. I had thought of writing a how-to, but 1) i could not write "how-to", only "what I will do next time", & 2) I dont think I have that much to offer-so much was flushed out in this post. Anyway, if there is interest I will cut and paste some things together.

Differential replacement, On-car, Driver's wheel On, Working Alone* (*Freeing lower ball joint in Axle Removal process may require assistance as described)

SKIPS GM REQUIRED DIFFERENTIAL END PLAY TEST--YOU ARE AT YOUR OWN RISK

See parts list in OP, only needed differential and diff thrust bearing & only used new thrust bearing b/c I got OE pretty dirty w/ my trial & error.

See Bill's how-to remove an axle. I originally could not get pry bar to seat properly, then turned wheel to right (working on right wheel) and pry bar slipped in perfectly. Bill's a rock star.

See Trannyman's 4t65e differential install. I didn't have any evenly tappered chisels, but got lucky & grabbed a used J-42562 off ebay for $10. There's nothing majic about it, any similar chisel should work.




Trannyman's write up is for off car, so just picking up where on-car is different.

In order to remove Tran Ext Cvr, the Transaxle Brace must be removed first. As described above, not that easy too get to. Remove Trans Ext Cvr & Transaxle Brace bolts. Leave Tran Ext Cvr on.
Carefully rotate Tran Ext Cvr in order to access VSS bolt, bolt is on backside of sensor. Remove VSS bolt.
Remove VSS
Remove Tran Ext Cvr.
With tool/chisel, remove Differential as described in trannyman's write up.
With puller and blocking remove VSS Reluctor Wheel from Diff.
Install VSS Reluctor Wheel on new Diff.

If the car STAYS in P, the Park Gear should be engaged & Park Gear should not move. However, it seems neccessary to disengage Park gear in order to align Diff gears/remove/install Diff. So, see tips above about Park Gear Thrust Bearing.

Remove Park Gear and Park Gear Thrust Bearing.
"Glue" w/ Trans Goo, grease, vasoline, eg, Park Gear Thrust Bearing in place.
Install Park Gear Thrust Bearing & Park Gear.

Now the fun part.

Note the Output Shaft slides horizontally, in/out 1" or so. Note the difference in relationship of the Output Shaft splines and retaining clip to the Sun Gear.






Crawl under center of car, with feet by front license plate and staring at oil pan. With your right hand, reach up/around and grab Output Shaft retaining ring. With your left hand, reach up/thru LCA/chasis and grab driver's side CV Axle Inner Boot. I know... Its not really "grabbing", more pinching, forking, claw action. Now, while pinching/squeezing the drivers CV Acle Inner Boot w/ left hand, use your right hand to push & pull the passenger side Output Shaft. Thru the Boot in your left hand, you will feel the Shaft slide in/out on the drivers side. The Shaft moving in your left hand is what you will need to "hold" in place--ie PRESS TO THE RIGHT/PASSENGER SIDE THE BEST YOU CAN W/O DAMAGING BOOT--when it's time to tap Diff on /compress the retaining ring.

Go back to wheel well and install Diff as far as possible before retaining is compressed. W/ the gears aligned, it should slide in far enough to support its own weight.

Crawl back under the car as before, w/ oil pan drain plug in your face. W/ left hand, squeeze shaft thru Boot, press and hold shaft as far to passenger side as possible, and at same time, with a hammer in your right hand, tap on Diff, past the retaining clip. Trannyman's write up has pics, but its obvious when it sets. Once the Diff is on shhaft past the retaining ring, the Planetary Gears have to be aligned w/ Ring Gear, not close, but flush. Twice I thought I had it right, but Tran Ext Cvr did not fit. I was rotating gears & rotating Diff to get them aligned, finally out of frustration, I pulled the Diff outward applying pressure to retaining ring, wiggled it, press it in hard & heard a double click. This time the Tran Ext Cvr fit on perfectly flush against Trans.

Slip Tran Ext Cvrt back off enough to reinstall VSS & VSS bolt.
Reinstall Transaxle Brace & Trans Ext Cvr blots.

Reassemble.....


With the help I got here, this worked for me. Car is literally running and rides better than ever.

Bumping a dusty thread I know.
The diff carier grenaded and took out the trans ext casing in my '04 gt?
vin 2GWP22341365000
They said they
1. didn't know if it was an hd trans?
2. didn't know if it was a GT 1,2 or P?
3. didn't know if it the diffs are the same?
all they could tell me was was M15 and F83.
Also wondering if the diff blew is there other trans probs I should look for?