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Adam001

LT230 loose differential bearing - ok?

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Hi,

Questioning myself here. I bought a LT230 transfer box the other day to rebuild. When I got down to the differential shaft/housing it has 2 bearings, one on each end. The end that goes up against the diff (diff bolted end) was tight and came off with a puller. The other end which has the large 2 flats staked nut and has all the output gears etc just came off, no puller/press needed. I figured this meant the bearing had spun and the housing needed replacing, these are super expensive so decided to just get another box...was the same!! So I took apart the one on my truck, same again!

I've emailed Dave Ashcroft for his view on this, but what have you guys come across when rebuilding these?

Picture below of the end i'm talking about (this one was the worst)

20200615_171751.thumb.jpg.196bdf12b7dba3c640df14ea181c3c5c.jpg

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I’d be interested in what Dave says about this but looking at the manual it looks like the bearing should be tight as the front is as it needs removing with a puller.

8B9618D5-003D-451F-A16D-09F17A05A750.thumb.jpeg.35e5e2843a8d4563edefce3a0971aebe.jpeg

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Yeah that's where I'm at, makes me wonder about reconditioned transfer boxes to be honest (from less reputable people that is) so far on the 3 boxes I've stripped many components are out of "spec", such as yokes, and dog clutches, intermediate shafts etc. I struggle to think I've got 3 that are out of the ordinary. So how do they make money when they should be replacing so many components!  Hmm

Daves pretty good, sure he'll come back to me monday/Tuesday or something.

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Adam, I stripped down four lt230s over Christmas. Two of them were like yours with spun bearings which just dropped off but they should be a press fit. The other two I had to pull the bearings off but it had been thrashed at some point and the planetary gear bronze washers had disintegrated and the gears worn themselves into the centre diff. they seem to tolerate a lot of abuse and wear. I kept putting off building one good one as I wasn’t happy with the wear. 

I eventually got lucky and scrapped a 300tdi disco which had been fitted with what must’ve been a new lt230 late in its life as was late td5 spec with bigger centre diff bearings and absolutely no wear whatsoever. As disco 2s are dropping like flies now perhaps look to get an lt230 from one which as been used only on the road.
 

 I retained the td5 “Q” 1.2 gear set, had my casing sleeved by Ashcroft, rebuilt the centre diff to correct tolerances with Ashcroft centre, Syncro gearboxes hardened intermediate shaft, fitted all new Timken bearings throughout (I did get NTN initially but they were slightly out of tolerance and the input gear would not shim correctly) It’s now a really nice quiet box with almost no driveline slop (I rebuilt and reset the diffs and fitted an Ashcroft ATB to the rear diff at the same time)

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Yeah I've done exactly that. Bought a disco II box with no diff lock hoping for a unabused box. Lovely clean oil but still the problem with the bearing. Seems a complete gamble! There's another thread on here from back in 2010 which also didn't get a conclusion on this bearing issue.

So thinking ill probably need to get a new diff centre I've hit another problem...they don't seem to exist. There are 2 types, one with the small splines, FRC7926 which seems to be superceded to FTC5207 but the larger spline one I can't find anywhere! Unless all the sites have it wrong and FTC5207 is not a supercession but rather the newer version with the larger spline.

May end up having to salvage it anyway!

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Scrap that, found the later differential, LR055682, even more expensive!! I really doubt reconditioners replace them at that massive price and make a profit 

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I stripped a few more down a few months ago and think I’ve got an earlier one in good condition, not a lot of use to me for my Puma (I dread to think what that one is like!) I may part with it.

I wondered the same thing regarding reconditioning! 

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Adam, do you have the option to switch to a Borg Warner transfer box? It might solve the issue you are dealing with depending on the vehicle etc.

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This wear is common and it is a problem for us but many customers spec the ATB centre diff which gives us a reasonable supply of stock diffs for other rebuilds.

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Yeah I'm hanging in that conflict now, between rebuilding my not too bad, but worn, shaft (58mm), buying a new replacement for around £400 or just going for the ATB (Which to be honest I don't need). I'm surprised it's not a topic discussed more often as it seems really common!

 

On 6/28/2020 at 8:36 PM, oneandtwo said:

I stripped a few more down a few months ago and think I’ve got an earlier one in good condition, not a lot of use to me for my Puma (I dread to think what that one is like!) I may part with it.

I wondered the same thing regarding reconditioning! 

 

Curious! Is it the earlier 53mm selector spline or later 58mm spline?

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Earlier 53mm one. In fact there’s a complete transfer box, I saved one good spare of each component.

ill dig it out later

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So I think my summary on this is it's a poor design! Mine is not too bad, more of a clearance fit with a worn bearing (I'll put up photos later).

I'm going to use it, it's likely a new bearing will remove some clearance and then I plan to use a bearing retainer, just need to decide between loctite 620 or 660 for the application. 660 makes sense but 620 i think is stronger.

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Can l assume that the transmission will carry on for years with this bearing spinning in the housing?

Not that you’d put it back in like that, but there’s no need to dismantle the transmission just to check this bearing.

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I figure the failure mode would be pretty slow to represent, probably start with slightly higher oil temperature from the friction then as it wears more cause a misalignment in the gear mesh and wear the bearing out. Failure of the bearing/shaft could happy at some point but guessing it would take quite some time!! Considering the one on my 300k mile box had spun i'm doubtful anything would really go bang!

I'm not that worried,  just don't like doing things badly and knowing it's like it means sods law is not far behind! Ignorance is bliss!

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Got the bits from Ashcroft, forgot to order diff thrust washers so once I've got those ill rebuild this bit and pop some photos up should others get the same issue!

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Figured I would update this for others. Rebuilt this carrier now and more than happy with it (for now).

Cleaned the shaft up, bearing did not need to be pressed on but is not visibly loose

20200725_143718.thumb.jpg.6d795d4ed9296bde34a924c0d8e6cff5.jpg

so went for loctite 660

20200725_143730.thumb.jpg.b007292aa226744e432bb58053f558b6.jpg

small bead around the shaft just behind the threads, then pushed and spun the bearing around to make sure it had a even coverage

20200725_144410.thumb.jpg.df92940de196fbd985194a8218b5bf80.jpg

New nut etc and torqued up correctly

20200725_145157.thumb.jpg.270429181cc03b8aa9267ae7ed1b0aa5.jpg

 

In future I don't think I would hesitate to do this again, these loctite products get great reviews

 

Adam

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Your experience of recon units matches mine - that the majority are all con and no “re”.  There seem to be only a handful of decent recon companies out there, and they charge much more because their shop overheads are higher (better facilities and better staff) and they replace a lot more parts with better quality sources.  It doesn’t mean that expensive equals good, but cheap rebuilds always cut corners and return units full of parts that should have been scrapped.

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