Replacing front diff

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Deb'nKJ

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Pt. 1 – remove front drive shaft:

OK so here’s where I’m at, unbolted, rear flange disconnected, front flanges move freely against each other – but won’t fully separate because there’s not enough room for the shaft to go back that far. Have I done something wrong? If not, what’s the answer?

Fully accept might have to remove exhaust, which should provide some wriggle room, (& already mentioned elsewhere that’s on the agenda, anyway) – but what’s the trick unplugging the up-stream sensor? I can touch the connector but not hold it to pull it apart & certainly can’t get a screwdriver to it to unlock it.
 

JeepJeepster

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What are you working on?

On my 04, I was able to push the rear of the shaft (tcase end) up above the tcase and towards the rear of the Jeep so I could get the front out and down. Then it came right out.

From what I understand, some years are more difficult than others. No idea what years are more/less difficult.
 

JRB

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Same way on my 2007 as JeepJeepster, hopefully it works for yours as well Deb'n!
 

tommudd

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yES GET REAR OUT A BIT, THEN PUSH IT UPWARDS WHILE PUSHING THE DRIVESHAFT SOMEWHEAT SHORTER THEN FRONT WILL COME DOWN OUT AND REMOVE
 

Deb'nKJ

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Well I thought I'd tried every which way but always came up against not being able to get past the TC flange but maybe I didn't try up & over. So thanks for that, it'll be what I'll be concentrating on next Saturday: almost looking forward to it - so you may have detected a distinct change of attitude.
Ironically, with the driveshaft out of the way I might just be in a better position to disconnect the up-stream oxygen sensor, but just so I'm prepared - what's the trick here?
 

J.C.

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Well I thought I'd tried every which way but always came up against not being able to get past the TC flange but maybe I didn't try up & over. So thanks for that, it'll be what I'll be concentrating on next Saturday: almost looking forward to it - so you may have detected a distinct change of attitude.
Ironically, with the driveshaft out of the way I might just be in a better position to disconnect the up-stream oxygen sensor, but just so I'm prepared - what's the trick here?
I have just finished replacing the front propeller shaft on my 2007 KJ CRD.

If you have a V6, then the exhaust joint probably has to be unbolted.

This section from a Service Manual has the description headings reversed.
The first section is actually showing the exhaust for the V6.

Once the 6 bolts from each CV have been removed, the rear (Transfer Case) end is first to be taken out by compressing the shaft spline towards the front and sliding the rear CV up and off the flange. The shaft can then be dragged back a bit with the rear CV sliding above the flange, but it tends get hooked so will need to be wriggled a bit. This allows the front CV to be removed from the flange on the front diff.

NOTE:
Check that the front output shaft (flange) on the Transfer Case does not have lateral (up/down) movement in the bearings, as this is a source of vibrations, too.



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J.C.

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Well I thought I'd tried every which way but always came up against not being able to get past the TC flange but maybe I didn't try up & over. So thanks for that, it'll be what I'll be concentrating on next Saturday: almost looking forward to it - so you may have detected a distinct change of attitude.
Ironically, with the driveshaft out of the way I might just be in a better position to disconnect the up-stream oxygen sensor, but just so I'm prepared - what's the trick here?
I've come into this thread a bit late and am wondering why are you replacing the front diff?
 

Deb'nKJ

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I have just finished replacing the front propeller shaft on my 2007 KJ CRD.

If you have a V6, then the exhaust joint probably has to be unbolted.

Yes I do & yes I was resigned to that (the cats are universal stainless steel ones and the welded joints are far from gas tight; something more easily remedied on the bench)

This section from a Service Manual has the description headings reversed.
The first section is actually showing the exhaust for the V6.
So far, I've found the SM well up to Haynes standards
Once the 6 bolts from each CV have been removed, the rear (Transfer Case) end is first to be taken out by compressing the shaft spline towards the front and sliding the rear CV up and off the flange. The shaft can then be dragged back a bit with the rear CV sliding above the flange, but it tends get hooked so will need to be wriggled a bit. This allows the front CV to be removed from the flange on the front diff.
That accords with what TM suggested (almost the opposite of what the SM says) so that'll be my approach on Saturday
NOTE:
Check that the front output shaft (flange) on the Transfer Case does not have lateral (up/down) movement in the bearings, as this is a source of vibrations, too.
Vibration's not an issue, but thanks for the thought.
Oh, & I'm having to replace the diff 'cos I cracked an axle tube :
 

Deb'nKJ

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Fist major obstacle (for me) overcome & the front drive shaft's now behind the back seat. Next was an unexpected diversion, because the rear hatch/window wouldn't latch. As it was starting to rain I adjourned for coffee, which inspired me to temporarily reconnect the battery, used the fob to lock the doors then, standing behind the Jeep, unlock them & - lo & behold, the latch snapped open.
So, problem solved, back to the job in hand. My intention was to remove the exhaust next (so I can get it welded) but must make refitting the driveshaft easier but decided to tackle those diff mounting bolts that won't draw out because they'd hit the lower control arms. My thinking was to undo the nuts & withdraw the bolts enough the cut them off under the heads more easily. Will then have a pattern to shop for replacements while I have a week off. Unfortunately, I don't have a suitable wrench down here in Devon, as my main tool box is up in London, so that will have to wait. Meanwhile, can someone tell me what size those bolts are?
 

tommudd

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YES that is the way you do it, been saying all along
Loosen the two forward cut them off and then when reinstalling just install the bolts the way they should of been from the factory
No loosing the LCAs or anything , super simple
 

Deb'nKJ

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Obviously the diff's fitted before the control arms so that's what's easiest on the assembly line - & who cares what problems it causes for others further down the road.

Although I can't do that that job this week, it is an ideal opportunity to get the replacement bolts, but I'll work something out.
 

Deb'nKJ

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So, finally went back to where I left off & managed to cut the heads off those bolts, push them out & fit the new ones, just to keep everything in place 'til the time comes.

Used my ever faithful 3" cordless angle grinder fro Lidl's, highly recommended (even the own brand cutting wheels are really good. I have no reason to doubt the equivalent from Aldi is just as good, their products are only distinguishable by their colour & packaging.

Moved it nearer to where I want it to start serious dismantling &, curiously, that awful knocking (which I originally thought was a CVJ) has gone, so was that the front drive shaft? I had no reason to look at it closely when I finally got it off, but there was nothing obviously wrong with it.

Took the opportunity to clear up the now revealed cat litter used to absorb the diff oil when I cracked the axle tube - & when I dumped the 1st shovelful, I saw something glinting; it was that long lost 10mm socket: since replaced, but still pleased to have it back.
 

Deb'nKJ

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Saturday managed to get the KJ into the optimum position for the remainder of the job but these dark days afore Christmas only allowed enough time to reacquaint myself with the underside & decide what to do next.

Sunday I had a little more time, once I'd psyched myself up to venture out into the cold, & returned to removing the front part of the exhaust (the universal cats. have been indifferently welded in place & are porous, especially around the top. & it should make replacing the front drive shaft a little less of a pain). Finally managed to disconnect the lefthand O2 sensor, luckily I hadn't replaced the battery tray after I'd removed it in my search for that wretched 10mm socket. Also got that manifold/downpipe clamp loose, a real PITA because of the position of the bolt: t'other side should be easier, as I've loosened the nut, should be able to get my modified deep 10mm socket on it &, generally, there is a bit more room. So that's something to look forward to for next weekend ;)
 

lfhoward

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Inspiring that you are doing this job in your driveway. Keep going! I am living vicariously through this story because I want 4.10’s also. Unfortunately there were no 4 cylinder KK’s so I can’t swap diffs to make it happen.
 

tommudd

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For anyone reading and for clarification, YOU DO NOT have to remove the exhaust to get the front driveshaft out
Plus reading the service manual will just confuse you , plus Haynes and all of those are worthless on anything more than showing how to put the key in the ignition LOL
 

Deb'nKJ

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Right here we go, trying to pick up where I left off.

Driveway? I'm doing this out in the street (albeit 1/2 across the the end of the drive)!

I didn't mean to suggest I had to take the exhaust off, just that as it was coming off anyway, it made sense to do it at the same time & (getting ahead of myself here) it certainly did make replacing the front driveshaft easier - just as well, it transpired, but will return to that all in good time.

Had 2 weeks off over Christmas/New Year, primarily to get this job done, so ran out of momentum. Of course I couldn't have anticipated that in that time (apart from a short spell on Christmas Day) there were only 2 afternoons in that whole fortnight it didn't rain. Net result, got the righthand downpipe disconnected, only to find I'd still not disconnected the upstream O2 sensor (as reported elsewhere) but, fortunately there was enough slack to be able to leave the exhaust on the ground until I could return to it. Situation is now getting rather desperate & job really has to be completed by end of the month so I can get it in for inspection. Soon as I got back to work in the New Year, I managed to get last Thursday & Friday off, so had 4 days to get the job done, come what may. The hope was to get a few preliminaries done the weekend before but circumstances conspired against me (i.e. the XJ had other ideas - & part of the back fence blew down).

Anyway, it's getting quite late here in London town, & don't want to try your patience too much, so . . .
to be continued:
 

Deb'nKJ

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OK, so now where was I?

ah yes, fast forward to last Thursday, day 1 of the 4 day weekend must get it done hit. Except I first had to swap in another front axleshaft on the XJ that's the only running one of 4 Jeeps (I'd done the job the previous weekend only to find the rotor wouldn't fit, too late to start all over again) Once I was mobile again there were a few errands to run, order those fence panels (remember?), go to the bank, get some groceries (well, I've got to live for 4 days) really to clear the decks, so it was dusk by the time I was ready to start on the KJ: thought maybe I could get to that dam' O2 sensor from within the engine compartment (that's how I tackled the LH one - with the battery & its tray already removed). It might be possible with the airbox out of the way but, despite having no apparent fasteners, try as I might, I couldn't shift it - & it was dark by then.
Friday morning's start was slightly delayed by seizing the opportunity to get my "Autumn booster" Covid jab but then get stuck in seriously.
1st, that O2 sensor, not such a pita after all, nor the LH exhaust, once I accepted the X-member'd have to come down. I dealt with that at the time in "what I did today" so, moving quickly on. LH axleshaft - I knew the ABS sensor wouldn't come out, I suppose I could've unplugged it inboard, but there just so many clips to wrestle with to release the wire I opted for removing the hub (do I hear sucking of teeth/see shaking of heads?). Did wonder about those ridiculously small, deeply recessed, bolt heads but given the right socket (T14?), a little pre-emptive heat & a liberal dousing of penetrant (for my fellow Brits may I recommend GT85? Made by Dutch WD40 with PTFE as the active ingredient!) about on a par with those strange XJ bolts - providing the flutes haven't rusted away - of which I have some experience (& nothing like the nightmare that was a certain WJ I bought in a mad moment). Don't now remember how I did it to replace the RH axleshaft but the problem of the LH hub nut was solved by a combination of a 31x10.5 MT on an aftermarket wheel that had a centre hole larger than the o.d. of my 36mm socket and a yard of square section tube I'd found by the side of the road + an 18" breaker bar. (I've skipped removing caliper, bracket & rotor because that's all routine maintenance stuff, so isn't useful or interesting). Fortunately I'd cut my teeth on replacing the RH axleshaft so getting the LH one free of the splines in the diff. was no big deal (although I couldn't remember whether to disconnect the top or bottom balljoint) but this time didn't have to loosen the top of wishbone. If only you could draw the shaft out through the knuckle, life would be so much easier - but I digress!
Moving round to the other side (out in the roadway, but advantage of it being a weekday was there was even less traffic than usual) I tackled slightly differently, as had already destroyed the ABS sensor, & removed the knuckle, hub & shaft as a unit: I bit unwieldy & may regret it come reassembly, but . . .
Given how early it gets dark at this time of year (& how cold it then suddenly gets) that seemed a natural break, especially as clearing up & putting everything away was going to take a little while. (I've grown out of working into - or even thru' - the night to get the job done.)
Come Saturday morning, reasonably pleased with my progress (yes I know I'm already 2 days into what TM considers a 35 minute job, but therein lies the difference) so not prepared to give up my ritual of a sortie out over Dartmoor (my local National Park) to commune with nature, restore my sanity & have breakfast. Besides, it was only 27* when I got in the XJ, so might not have wanted to start quite that early anyway. So, we're back & under the KJ, getting an idea of what's involved (at the back of my mind I have TM's words about not telling me of the problems I'd encounter). Those of you with good memories & infinite patience will recall I'd already tackled the 2 front mounting bolts, so the nuts weren't much more'n finger tight, off they came & the new bolts almost pushed out. The rest of it was pretty straightforward, poor access wasn't a real issue (even with the floor jack under the diff. proper) & nothing was impossibly tight. Only 2 things caught me out, I undid the 3 bolts that attach the LH top mount to the diff. whereas perhaps I should've taken out the bolt thru' the bush - the whole thing was almost on the deck before I noticed the breather!
Really should've put finger to keyboard that Sunday evening on the train back up to London, but was distracted by shopping for tyres on-line, & now honestly can't say at what stage I called it a day (that old failing light, plummeting temps thing again) & make an early start on Sunday, but next was drag diff out from under & up the driveway, transfer some hardware onto the "new" one & get that under the Jeep, 1/2 on the the jack, tipped up so tailshaft was just touching the X-member, so as the jack went up, the tailshaft would slip over the X-member & act as a pivot. All went quite well, not to difficult to align all the mountings, once I'd refitted the RH bracket (those goes round the axle tube) the right way round: idiot that I am I'd fitted it back-to-front. Managed to replace the bolts in the front mounts (they're much lower than the rear ones) really easily & then, of course, with the front supported on pivot points & the whole thing pretty well aligned it was fairly simple job gently jack it up keeping an eye on the two top mounts, to make sure the bushes entered the brackets on the body. Of course it would've been easier with a helper - but, mercifully, so much easier than swapping a transfer case in an XJ.
Not much time left now before clearing up, getting cleaned up, changed, have something to eat, pack & set off again on my travels but really wanted to get the drive shaft back in (on?). That was clearly going to be so much easier without the front 1.2 of the exhaust but it took me a little while to work out which way round it went - & which bolts were for which flange (just remember how much time had passed since I'd removed it). Lining up the rear flanges & getting the 1st bolt started was a bit of a pain (can't believe I'd not marked it, but certainly couldn't see any). After that, it all went quite well, even without my right angle 3/3" drive electric ratchet, which I'd mislaid.
That's it, up-up-to-date, still not finished, despite my avowed intent & best efforts, but now (whatever the weather throws at us) the front end's got to go back together this weekend. I feel much more confident with it now, so it should be a simple nut'n'bolt re-assembly job.
Wish me luck - & I'll be back!
 

Deb'nKJ

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No more epics (but thankyou those who stuck with me), just easy to digest bight-size chunks. Didn't have much time my the time I got back from my Saturday morning constitutional & return via local discount emporium as it's having a 15% off everything sale. Among the stuff I came away with was a 3/8-1/2" adaptor (costabout$1) which means I could cheat & use my electric right angle ratchet to run up those 18 & 22mm nuts :)

So tackled the right side 1st as that required the most re-assembly. I was right, that axleshaft/hub/knuckle is one unwieldy piece of metal, so I gave in & removed the wishbone (no big deal as it was off in the Summer - although the bottom bolt was a bit of a struggle to replace 'til I hit on sitting on the ground loading it in the right direction with my right foot, leaving both hands free to insert bolt & start the nut). The whole thing then slipped into place so easily I couldn't at first believe the shaft had engaged with the splines in the diff. The next problem was the piece of 2x2" I'd stuck in the caliper so I could move the Jeep without re-assembling the brakes all that time ago - or rather removing it - but a little perseverance prevailed.
Fortunately the new pads arrived yesterday (that's a topic referred to in another thread) but was a little dismayed to have to resort to a using a hammer to locate the top of the back pad o_O. Not as dismayed as I was to find the caliper was hung up in front of the knuckle :oops:. Too dark to continue as batteries in both lights need charging but I'm hoping that (if it doesn't take too long to find the keys) with the steering unlocked I can threadle the caliper round the back of the knuckle. If I have to break the top balljoint again, it's not the end of the world - but I'd rather get on with the other side.

'til tomorrow then . . . ;)
 

Deb'nKJ

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So, I'm on a train up to London, leaving behind KJ that's back down on all 4 wheels & the job' largely done.

Yes, I did have to have break the top balljoint again (to get the caliper back where it was supposed to be) but my biggest concern was laying into the knuckle with a 2lb hammer that early on a Sunday morning; fortunately it only took 2 sharp blows & the taper popped out.
I have to replace the ABS sensor &, curiously, the new one has all the clips, although they are removable but not the grommet where it goes thru' the inner fender. Fortunately, over Christmas, I found my single edged razor blades so was able to surgically remove the old grommet, so I can superglue it back together once it's on the new wire. That will have to be a little job on its own because I need the Jeep down on the deck to reach the connector in the engine compartment.
The balljoints on the other side were a pain because once the nylon insert in the nut reached the thread the ball turned in the taper. Had to resort to self-locking needle nose pliers on the thread :eek:.
Thought I'd realised what the problem with the back pad was on the right - but the one on the left was so much worse, I ended uo re-using the best of the old ones just to get the job done. I think it's going to take I little more than taking a file to the paint on the tips of the "ears" - minder to take flap wheel to them, using an old one for reference, but afraid of taking too much off. Still that's a job for another day, when there isn't so much hanging on it.

No oil in it yet, too cold to pour 80/90 into a sueezy pack, never mind squeeze it into the diff & I forgot to take the oil into the warm in advance - but it's indoors now, ready for next weekend. Last job is to refit the battery tray (not strictly part of the job, but having it out made disconnecting the upstream 02 sensor marginally less difficult. Took it out so long ago, for the life of me, I can't remember how to fiddle it round everything & up under the PDC & decided it wasn't the sort of thing to do in a particularly unpleasant wind & against the clock - so I think that's next Saturday afternoon's activity ;)

Of course, the exhaust still has to be welded & put back, but that won't stop me firing it up & just seeing if it'll move back'ds & forwards (or maybe t'other way about) in 4WD - hopefully without the knock that kicked this whole thing off. :rolleyes:

Then, I can say replacing the diff's done & close this thead.

Do appreciate you sticking with me guys, has helped focus my attenton.
 
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lfhoward

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Just read through your whole story, @Deb'nKJ. Thanks for the details and the entertainment.

Quick question (maybe I just missed this):
Were you able to remove the front diff with the lower subframe still in place? If you didn’t have to unbolt the subframe, did you slide the diff out the side, down, or to the rear to get it out?

I am thinking of doing this job so that I can regear the front diff in my basement workshop. I like to be able to picture the process in my head before I go and do it.

Oh and I looked up those front bolts that you had to cut through as “BOLT, Hex Flange Head, M12x1.50x90.00” in the 08 parts manual. Do I want to make the replacement any shorter than 90 mm so as not to contact the lower control arm when I reinstall them backward?
 

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