CRD/V8 diff upgrade.

[07commander]

if any body could do it, it would be clarky

[Clarky]

Valpacer did it first, I just fumbled around till the answer fell into my lap. US spec CRD's are factory 3.73.

$200 Canadian for the tcm which is $205au.
All up including the failed (only half fail) custom TCM from OST I didn't spend the $1200 I was quoted here in OZ.

In case I haven't mentioned it the SRT8 TCM went into limp mode in low range.

I would hate to have fitted the 4:11 gears as I would still be searching for answers.

[mjl]

what an interesting read Clarky. So was $1200 the final cost? What about driving with the changes - at 60km or 100km is there much change to your previous rpm's and how does it accelerate now? How about offroad - can you feel the difference? I have been reading up on this thread and others and its on my wish list...

another question i am looking into is the TC ratio's. I am actually fine with the daily drive of my Grand CRD but wondered if there are any kits or aftermarket experts out there that do a gear change/ratio change for the transfer case? I know there's one for the Rubicon that can change to 4.10 providing very good offroad crawling speeds and control but any ideas for the NV245.?

[Clarky]

Originally Posted by mjl

what an interesting read Clarky. So was $1200 the final cost?

No. The V8 QDII diffs cost me $2000 (delivered), If you are good at haggling you may do better.

The TCM cost me $205au delivered from Canada (there dollar is much the same as ours).

So cost would be around $2200au depending on your bartering skills. I spent around $500 on a custom tune TCM that didn't do the job.

I also fitted new lower control arms (that added to the cost but if yours are in good shape there is no need to) & JeePerf front diff bush's.

Replacing the bush's with any brand (original or aftermarket) I would say is compulsory as it is so easy with the diff removed & a real bit*! to do after it is in..

Originally Posted by mjl

What about driving with the changes - at 60km or 100km is there much change to your previous rpm's and how does it accelerate now?

At 100kph I am sitting on 2100rpm with 265/70/17 tyres, 110 is about 200rpm more which is about the same as original ratio's with stock tyres from memory. If you could fit 33" tyres then I would say 2000rpm at 100.

Originally Posted by mjl

How about offroad - can you feel the difference? I have been reading up on this thread and others and its on my wish list...

Before the change but with 265/70 tyres I would touch the brake on down hill grades to keep from speeding up, now (with the little I have driven in low) I actually have had to accelerate a little, just crawls down.

Originally Posted by mjl

another question i am looking into is the TC ratio's. I am actually fine with the daily drive of my Grand CRD but wondered if there are any kits or aftermarket experts out there that do a gear change/ratio change for the transfer case? I know there's one for the Rubicon that can change to 4.10 providing very good offroad crawling speeds and control but any ideas for the NV245.?

Honestly I don't think it is needed, 1st gear in the NAG1 is 3.59 compared to the (545RFE) V8 box's 3.00 first gear then the NV245 low ratio 2.72:1.

What you want is a Rubi-Crawler but alas they don't make one for the nag1
http://www.advanceadapters.com/produ...-transmission/

[mjl]

thanks yes i saw the Rubicrawler before and not for NAG1 unfortunately. OK so sounds like the V8 gears at 3.73 might be fine as i am going to engineers for anything over 2" tire increase, i just got some Commander Wrench rims to clear that damn nut so looking at 265/65R17s (might even try 275/65R17s but feel sure they will rub on full lock) but i will see how it feels in the bush, on sand and rocks before deciding if i need to change or not. Great write up though well done

[Clarky]

After 5 years the top Jeeperf bush has failed (centre sleeve has worked its way loose)

Don't know if its related but the new half shaft (right hand side) popped out on a trip out to Menindee Lakes. Didn't know that was the problem till I got back, that was 1000km of nervous driving thinking the front diff was going to explode.

Pulled the diff and inspected for damage and it appears to be good apart from needing a few seals and a new bush in the axle extension housing.

Parts on order, all from Aus except for the axle bushing (USA) which I now know I don't need as I have a brand new axle extension housing I ordered years back and it has the bush already installed .

Going with Super Pro bushings this time, I just don't have the time to wait for Jeeperf ones to be shipped from the middle east.