Nothing better then a Cummins in anything other then a Dodge, i'm looking for a 4bt myself do do another Cummins swap.
I'll be watching. Is your zf5-42 the gas or diesel trans, I used the Diesel trans in my Fummins behind a 12v and best trans out there.
Or are you using the smallblock zf5?
Sorry it took so long to answer you on this
@BLACKJKU but yes I am using the ZF s5-42 transmission.
It is the small block wide ratio gasser variant. I yanked it out of a 1994 Ford Bronco that was equipped with the EFI 4.9L 300 Cu. In. straight-6 motor. It was the bargain basement bottom trim XL, an ex USFS green ranger vehicle. Steel wheels, dog-dish hubcaps and non tinted manual hand crank windows. Bench front seat & rubber floor too. Oddly enough, it did have electric door locks and cruise control. The only options apparently. It had an 8.8 rear axle and whatever twin I-Beam semi IFS Ford used those years.
The new owner was converting it to a rock crawler on 1-Ton F350 axles and a 351W automatic from a parts F350 he had in his yard.
If it turns out the power band doesn't match as well as the diesel variant of this transmission, I will rebuild the interior guts with the diesel variant. However, I think it will be fine and for added bonus the gasser has a really nice deep crawler 1st gear vs. the diesel variant. I wouldn't have had to have the JB conversions 4:1 in the D300 but since it's in there already, I am not removing it now.
I will have almost exactly a 94:1 1st gear, low range crawl ratio with the 4.10 gears in the axles. Perfect for the Rubicon Trail, Fordyce and the Dusy-Ershim trails I frequently crawl. In fact, many times I will start out in 2nd or 3rd gear with the ratios at my disposal now.
The SAE to Ford bellhousing adapter on the 4BT is made for the small block bolt pattern so I can't connect the diesel variant to the Cummins directly.
I am not going with a dual mass flywheel so I won't have to worry about it exploding and causing damage to the ZF integral bellhousing. Something that does happen on the big block dual mass version occasionally.
I already have received the AA adapter kit for the D300 transfer case so it can mount to the ZF transmission. it is a 9925 I believe, same as for the C6 automatic transmission.
I have also received the motor mounts and in the coming weeks will start test fitting the entire drivetrain in the CJ. Everything has been cleared out to make room and take measurements. There is a 1" poly performance body lift on the CJ already so I shouldn't have to do any mods to the tub pinch seam at the firewall to fit this package. I decided to make life easier for me and order the Farmstrong Jeep CJ-7/8 mounts instead of engineering my own.
All clutch parts will be stock Ford. No custom anything in case I break down in the middle of nowhere I can go to any parts house or Ford dealer and get parts to fit. Straight forward conversion so nothing that is one-off anywhere on my rig except some steering and components used in the D44 I have up front. Everything else is parts that are common to production vehicles that are in junkyards or dealers will have the parts.
About the only thing I will have to do is custom bend the shifter lever for better dash clearance. The known thing about these conversions with the ZF is the relatively short distance from the bellhousing to the shift tower. Ford had the shifter close to the firewall in their trucks those years.
Again, I learned my lesson about custom axle shafts, bits & bobs. What happens when you break a part that is custom and have to contact the shop that did the work to get a replacement. NOT GOING THAT ROUTE EVER AGAIN.
If there weren't smog in CA on 1998 and up diesels, I would have considered another 4BT in our JKUR using the Allison 1000 6-speed transmission instead that was behind the Isuzu/GM Duramax 6.6L like what I had in my old Sierra crew cab long bed 2500HD. Great transmission that would perform marvelously behind the Cummins. Possibly the later ISB electronically controlled 16 valve version for more refinement in the later JK vehicle.
RR
