Help with Front Diff swap

[The Big Boulonnais]

Hi guys,

I came back from the "Chambon sur Jeep" yesterday with only my rear axle working. This is a 4 days Jeep only Off Roading event in the French mountains of Auvergne. Well worth to take a look on Facebook or Google it. I even met with Dennis from Terraflex and Dan Mick the Man from Moab.

Anyway I was lucky despite the damage as I could drive my KJ for the 9 hours ride back home in England (+ Car Ferry crossing!)

I only found out this afternoon once the Jeep was on stands and the factory skid plate removed that the front differential housing is cracked. It's quite bad about 1/2in wide over a length of 6 to 8 inches.

I searched on eBay this evening for a front diff to replace and I found one but it's out of a 2.5 CRD Manual year 2004 and mine is a 2.8CRD Manual year 2007 but still it is a KJ not a KK.

Could you knowledgeable Jeepers please help me with this dilemma because if it's the right Diff I need it Bad.

Many thanks,

Chris

 

[tjkj2002]

The 2.5 CRD's got 4.10 gears if I remember right.Will work but you will have to re-gear the rear diff to use 4wd.

 

[Porkchop]

Are not the 04 2.5 CRD and a 07 2.8 CRD 4.10s ?

 

[tjkj2002]

Are not the 04 2.5 CRD and a 07 2.8 CRD 4.10s ?

No since the 2.5 CRD is a non-turbo engine while the 2.8 is a turbo engine.The 2.5 CRD is no more powerful then the 2.4 gas KJ.

 

[The Big Boulonnais]

The 2.5 CRD's got 4.10 gears if I remember right.Will work but you will have to re-gear the rear diff to use 4wd.

Thanks for the info Troy. So to get the same Diff with the same gears it must come from exactly the same model then.

Would a front diff from a 2.8CRD with Auto gearbox fit my 2.8CRD Manu ?

 

[Billwill]

No since the 2.5 CRD is a non-turbo engine while the 2.8 is a turbo engine.The 2.5 CRD is no more powerful then the 2.4 gas KJ.

Not quite correct!

The 2.5 CRD (Export) and the early 2.8 CRD (Exports) do have a turbo but it is a fixed-vane turbo not a variable-vane turbo as fitted on all 2.8 CRDs from 2005.

And the 2.5 CRD has a lot more power and torque than the 2.4 gasser!:icon_eek:

And my 2002 Export 2.5 CRD Sport has the 4.10.....with Trakloc at the rear.

 

[The Big Boulonnais]

Not quite correct!

The 2.5 CRD (Export) and the early 2.8 CRD (Exports) do have a turbo but it is a fixed-vane turbo not a variable-vane turbo as fitted on all 2.8 CRDs from 2005.

And the 2.5 CRD has a lot more power and torque than the 2.4 gasser!:icon_eek:

And my 2002 Export 2.5 CRD Sport has the 4.10.....with Trakloc at the rear.

So do you think the Front diff of a 2.5CRD year 2004 Manu gear box would be ok for my 2.8CRD year 2007 Manu ?

I know mine has a ratio of 3.73 but does the 2.5CRD Export are all 4.10 ?

 

[Cardhu]

So do you think the Front diff of a 2.5CRD year 2004 Manu gear box would be ok for my 2.8CRD year 2007 Manu ?

I know mine has a ratio of 3.73 but does the 2.5CRD Export are all 4.10 ?

all diffs are dana 30 A so they "fit".

your looking for another set of 3.73 or you will have to regear the rear to 4.10's at the same time if you buy the 2.5 diff.

Personally i think this is a good time to look for trutracs or lockers and spend 3 K.

 

[The Big Boulonnais]

all diffs are dana 30 A so they "fit".

your looking for another set of 3.73 or you will have to regear the rear to 4.10's at the same time if you buy the 2.5 diff.

Personally i think this is a good time to look for trutracs or lockers and spend 3 K.

Do you know if there is a mark somewhere on the Diff that shows what the ratio is because I am buying this over the phone with breakers who haven't got a clue.

 

[Billwill]

Do you know if there is a mark somewhere on the Diff that shows what the ratio is because I am buying this over the phone with breakers who haven't got a clue.

I know that my 2.5 CRD has a sticker on the rear axle that states that it is a 4.10 so obviously the front is also a 410....don't know if it has a sticker.

You should be able to tell the diff ratio by turning the input shaft a certain number of turns and counting how many turns the output does then work out the ratio.:icon_eek:

 

[The Big Boulonnais]

If I found a breaker with an Auto 2.8 CRD could someone please tell me if a front diff from a 2.8CRD with Auto gearbox would fit without regearing my 2.8CRD Manu ?

 

[TwoBobsKJ]

If I found a breaker with an Auto 2.8 CRD could someone please tell me if a front diff from a 2.8CRD with Auto gearbox would fit without regearing my 2.8CRD Manu ?

Darn if I can find it right now but I had a link to the diff ratios for the CRD auto and manual transmissions. And I think the ratio for the 2.8 CRD manual trans is 3.73. Unless I find out differently I'm going to go with that answer :favorites13:

Bob

 

[The Big Boulonnais]

Darn if I can find it right now but I had a link to the diff ratios for the CRD auto and manual transmissions. And I think the ratio for the 2.8 CRD manual trans is 3.73. Unless I find out differently I'm going to go with that answer :favorites13:

Bob

Hi Bob,

Thanks to look into my problem mate but I just found in LOST a link to the Automobile-Catalog the complete Catalog of Cars, car specs database and according to them the 2.8CRD Auto has a ratio of 3.73 but the 2.8CRD Manual has a ratio of 3.55 !!

So if they are correct and I think they are then I am in the S**T because there are not many Manual 2.8CRD in the UK breaker yards.

If I could find a front AND rear diff of a 2.5CRD with a ratio of 4.10 do you think It would be just a simple swap with my 3.55 ratio Diffs or would I be facing more issues?

 

[The Big Boulonnais]

Hi Bob,

If I could find a front AND rear diff of a 2.5CRD with a ratio of 4.10 do you think It would be just a simple swap with my 3.55 ratio Diffs or would I be facing more issues?

Hi guys,

I found a complete set Front and Rear Diffs coming from a 2.5CRD Manual year 2004. It has a 4.11 ratio but that could be a bonus since I lifted my KJ and fitted 31in tyres to it.

But can you guys who are in the know tell me if it's all going to fit with the existing drive shafts,CVs and transfer box of my 2.8CRD Manu 2007 ?

I am going to check if my CVs are not damaged anyway but if they have I will try to get them from the same Jeep.

 

[Billwill]

So do you think the Front diff of a 2.5CRD year 2004 Manu gear box would be ok for my 2.8CRD year 2007 Manu ?

I know mine has a ratio of 3.73 but does the 2.5CRD Export are all 4.10 ?

All 2002 2.5 Export CRDs were manual only....auto option I think was in 2003/4 or so I thought.


I do not know if all Export CRDs have the 4.10...it may be only the Sport model...not the LTD and may only have the 4.10 if the rear has Tracloc.

You need to count the turns of input shaft verses output shaft if there are no stickers to be found on the diff assembly.

And you do not want Tracloc, in case you are thinking of going 4.10 both ends,....mine works OK but you have to maintain the oil and friction modifier in it or you get problems.:shrug

Drive shaft/CVs may be different between 2002 2.5 and your 2007 as you proberbly have a six speed as opposed to the 2.5 5 speed manual.

 

[Cardhu]

Hi guys,

I found a complete set Front and Rear Diffs coming from a 2.5CRD Manual year 2004. It has a 4.11 ratio but that could be a bonus since I lifted my KJ and fitted 31in tyres to it.

But can you guys who are in the know tell me if it's all going to fit with the existing drive shafts,CVs and transfer box of my 2.8CRD Manu 2007 ?

I am going to check if my CVs are not damaged anyway but if they have I will try to get them from the same Jeep.

i know the 2007's are different in that they have esp , atleast in NA.

I don't know if that translates into issues. Also rear brake lines run differently so not sure what the implications of that are. You need somebody who has done a rear diff swap to comment that has seen the differnnce with the 2006 and 7 jeeps.

However, 4.10s would be ideal. Worst case scenario is to regear your current rear diff. If this is the road your on, a carrier replacement to another traction aid might be what you'd want too.

If the rear diff doesn't pan out you can always take out the front driveshaft untill you can get it regeared post front diff swap. Just no 4 wheel drive till resolved.

 

[TwoBobsKJ]

For what it's worth Tom Mudd and I swapped out the front and rear diffs on mine so I could go to 4.10's. I have no idea what year the front diff was from and the rear was from an '04 (mine is an '03.) I got my diffs from 4 cylinder gas/petrol KJ's from breaker yards as well.

The front and rear were both a direct swap - since there was no ABS or ESP alphabet soup stuff to worry about. Big Boulannais, check whether there are any differences in the brake lines or if the donor vehicle has electronic traction control or ABS brakes. If not you should be able to do a direct swap. It's not a technically difficult job though the parts you're dealing with are heavy so having a couple extra set of hands around is very helpful :waytogo:

There are KJ owners on this side of the pond who've regeared to 4.10's on their CRD's after going to bigger tires/tyres and really appreciated the improvement in drivability. I think the misfortune on your recent wheeling trip may be a very good thing for your Jeep in the long run.

Bob

 

[tjkj2002]

'06 and '07 KJ's rear 8.25 is completely different then '02-'05 KJ's due to ESP and 4 channel ABS.There is no rear/center speed sensor port in the '06/'07 8.25 diff since they moved a sensor and tone ring to the axle flanges.

 

[The Big Boulonnais]

'06 and '07 KJ's rear 8.25 is completely different then '02-'05 KJ's due to ESP and 4 channel ABS.There is no rear/center speed sensor port in the '06/'07 8.25 diff since they moved a sensor and tone ring to the axle flanges.

Yes that's a good point so I checked my rear axle. The axle flangles are bolted on the axle itself so I can remove them and put them on the 2004 axle so I'll have the sensors at each ends and I won't connect the center speed sensor of that "new" axle.

What do you think of my idea? Possible or not?

 

[tjkj2002]

Yes that's a good point so I checked my rear axle. The axle flangles are bolted on the axle itself so I can remove them and put them on the 2004 axle so I'll have the sensors at each ends and I won't connect the center speed sensor of that "new" axle.

What do you think of my idea? Possible or not?

'02-'05 KJ 8.25 axles themselfs are also different and will not work.The '06 and '07 axles will not work in the older housing since they deleted the tone ring behind the ring gear.