Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: gregwho on October 03, 2016, 10:00:54 PM

Title: How to know if a diff is shot
Post by: gregwho on October 03, 2016, 10:00:54 PM
On my WJ CRD, I think my rear diff is starting to whine, mainly between 30 and 70mph, and worse under acceleration (get much quieter if i let up on the accelerator).  Just wanted to check if the general consensus is that I need a rebuild?

I've looked up a company in the past and they wanted £500 per diff to rebuild, but I would struggle with getting the Jeep to them and picking it up.  Does anyone know of any services that come to you, remove the diff, rebuild and refit (Surrey ish area!)?  What kind of cost would you expect for a rebuild, is £500 about the mark?  What gets "rebuilt" in a rebuild?

Cheers all


Title: Re: How to know if a diff is shot
Post by: The Smiths on October 03, 2016, 11:25:31 PM
This is what it looks like when a pinion bearing has gone


(https://birtydastards.com/frm/proxy.php?request=http%3A%2F%2Fi219.photobucket.com%2Falbums%2Fcc124%2Fmds-houses%2Fjeep%2Fcumbria%2520july%252009%2Fth_S1053899.mp4&hash=7ba2db735e955544422150519162c17252db3093) (http://i219.photobucket.com/albums/cc124/mds-houses/jeep/cumbria%20july%2009/S1053899.mp4)
Title: Re: How to know if a diff is shot
Post by: Bubba on October 04, 2016, 07:34:21 AM
the truth is they can whine for a long time or many miles if leaking though you do need to sort it out i ran a zj for several years whining as an experiment to see how far it would go  i have all the tools and built many axles so it was not a concern to me
i sold it on to a birty who later sold it to africa

cost is very much a wild card but is not cheap anywhere 
Title: Re: How to know if a diff is shot
Post by: eastryjeep on October 04, 2016, 06:57:56 PM
What about an axle swap from one off ebay?
Various prices but would give the opportunity to do pads, disks, rubbers & hoses if you wanted.
Just need to make sure you get the right ratio, and do the job before it gets too cold outside!
Title: Re: How to know if a diff is shot
Post by: scrw on October 04, 2016, 07:52:38 PM
Have a set of WJ axles rebuilt by Bubba, regeared to 4.10, varilok, all new joints, done sub 1k miles since rebuild. Yours for £350
Title: Re: How to know if a diff is shot
Post by: gregwho on October 04, 2016, 09:58:40 PM
Hey scrw, thank you, sounds good!  Bubba rebuild sounds spot on too!  For the layman (that being me) what does the re-geared ratio mean?  I'm assuming its the number of times the wheel turns compared to something, and if so, is 4.10 better/same/worse than the current ratio?!  I'm ok with engine stuff and electrics, but have zero experience with diffs and transfer cases!

Are your axles the same as what I have at the moment (i've got the quadra-drive setup) and would they be a straight swap?  I'm guessing as much as I would love to do the work myself, time isnt on my side at the moment, so do you think this is millions of hours of labour to swap them out, or could a decent garage do it in a day or so?
Title: Re: How to know if a diff is shot
Post by: scrw on October 05, 2016, 07:52:52 AM
They are quadra drive axles. 4.10 is a slightly lower ratio than stock so you can go up a size or 2 on tyres without losing performance (245-75-16 or 265-65-16), with stock tyres your Jeep would be quicker off the mark with a little less top end for a given engine rev.

Swap wise, I have done it on my drive on my own in a day, a garage with a lift would do it in 1/2 a day, certainly less than a days labour. Only thing you may need them to swap is the front axle pinion yoke, it is set up for a propshaft with a UJ on, some jeeps came with a UJ front axle, most with a CV, but swapping the pinion over is a simple task.
Title: Re: How to know if a diff is shot
Post by: gregwho on October 05, 2016, 04:33:32 PM
I think you've just answered something else for me - about 8 years ago I put some new tyres on as didnt like the bicycle looking things that were on there (cant remember for sure but think they were 245 65 17), and swapped them for 255 65 17's.  I've always wondered why the Jeep seems to take a while to take off, and I'm guessing its because the diff ratio isnt right for the new tyres sizes?  Would the 4.10 ratio work ok on my tyres?

I'll PM you shortly to swap some details, and thanks again for your help!
Title: Re: How to know if a diff is shot
Post by: scrw on October 05, 2016, 09:29:56 PM
235-65-17 were a stock size, 4.10s will sort out the gearing with the bigger size boots. PM incoming