JK: Hemi Build

[DIY]

Will sound better as a manual aswell

[damage_man98]

To be honest i would have prefered the manual but when I bought the JK they hadn't properly released the manual kits yet so I bought the auto JK. I absolutley hate the 3.8 with the auto on the stock gearing. If I wasn't planning on the hemi conversion i wouldn't have bought the auto. I'm not sure how dificult it would be to change it to manual now. When I was talking to Jeep Konection about the Hemi swap I was looking at the possibility of changing to the manual as they were changing their manual to an Auto so i could have used their un required parts including clutch pedel etc.

All a bit late now as the money has now been paid including the auto. Will have to see what happens and if I have any problems with it then instead of a replacement auto the manual will be on the cards. Not worth worrying about until it happens. Its like the theory behind keeping the stock axles for the first part of the build. If I break them the only thing I've lost is time as i haven't factored in any value for any parts I can sell including the 3.8l engine and the axles. Anything i get for them will go to pay any extra costs I was not aware of which there are already a few that I hadn't budgeted for. Most of which are to do with the extra cost of the 6.4 over the 5.7 hemi. Only time will tell if the choice was worth while.

[itchy]

Awsome, cant wait to see this.

[Nudge]

Originally Posted by CRDSTU

Hi there Glen,

Your build sounds awesome, the stuff JK dreams are made of! I just wanted to inform you of a few ongoing issues my best mates 7lt JK has had since he started the build.

1. Broke New Atlas 4 Speed in 2 - it cannot handle the torque of the 7lt and wouldnt really cope with a 6.1lt given the big tyres, ratios and huge extra vehicle weight.
2. 2 Broken (throw away) NEW 545RFE Trannys. They cant handle the torque of the 6.1's or 7lts again with all the extra diff work, extra ratio's and vehicle weight.

This seems to be the achilies heel of the conversion process. The 5.7's dont have an issue and dont seem to cook transmissions unless your "Duning" on sand for prolonged periods of time and a heavy right foot.

From what I can gather and hypothesise on is the W5A580 Merc Tranny found behind the WH CRD's and WH SRT8's is what needs to be included in the equasion. They are designed as an Merc High Performance AMG box - rated my Mercedes to 788Nm of Torque. I've never seen or heard of anyone doing it but that doesnt mean it cant be done.

I'm really interested in seeing how you go. The transmission issue is the big one.

Good luck!

I think this was his problem....

You Tube

[Nudge]

hint hint,

http://www.transmissioncenter.net/4l80e.htm


Atlas 2 with this...http://www.high-impact.net/transmiss...e_brochure.htm

[JK07]

Buy the trany from aev bec they are diesel auto 545rfe tranny not dodge petrol tranny. If you have already paid the coins just pay some extra and get the diesel 545 tranny beefed up
Thats also one of the reasons why aev only sells 5.7 hemi do some more digging i am sure u will find a stronger tranny

[CRDSTU]

Originally Posted by JK07

Buy the trany from aev bec they are diesel auto 545rfe tranny not dodge petrol tranny. If you have already paid the coins just pay some extra and get the diesel 545 tranny beefed up
Thats also one of the reasons why aev only sells 5.7 hemi do some more digging i am sure u will find a stronger tranny

Agreed. This would be your best bet. If you do some serious research and reading on what's happening in the States, they've had plenty that are failing with 6.1's, 6.4's and 7.0ltrs.

Something to think about - if Jeep thought the 545RFE was good enough to put behind the 510Nm CRD Merc engine in the WH, they would have used it. Instead they chose the Merc's W5A580 because of its strength and reliability.
They also chose to use it behind the 6.1lt SRT8's for that very reason - 545RFE can not handle that power or torque reliably.

They did however use the 545RFE behind the 5.7 Hemi WH's because not only were they 500Nm but they dont have the massive surge of Torque that hits you in the back like the CRD delivers. The 5.7lt is a gradual surge that has a peak high up in the rpms so much less strain on the Auto.

Food for though.

There are afew people going down the road of installing or trying to at least, install the W5A580 Mer box, good for a factory quoted 788Nm or 580Foot pounds of torque. Yum Yum.