Wiggilez Posted June 28, 2013 Share Posted June 28, 2013 Will the AX-15 + bell housing from a 2nd gen dakota mate up to the 2.8 GM in my 86 comanche? Link to comment Share on other sites More sharing options...
GirsMJ86 Posted June 28, 2013 Share Posted June 28, 2013 96-00 Dakota 2.5L bellhousing: Connects to any Jeep 2.5L L4. Because of it's GM 60 degree V6 inherited bolt pattern, also works with any Buick FWD V6 and supercharged V6, any Chevrolet 2.8/3.1/3.4 V6, any Cadillac 4.1/4.5/4.9 V8 and with a minor modification, any Olds Aurora DOHC V8 and Cadillac DOHC Northstar V8. Also bolts to any Isuzu 3.2\3.5 DOHC V6, Holden (Australia) 3800 V6 and the LS4 5.3L V8 from the Impala SS. Although there isn't much reason to swap out for an ax15 while sticking with the weak 2.8L unless you currently have an ax4 rather than the ax5 or your ax5 is dying and you have access to the Dakota ax15. Otherwise I'd be swapping out that 2.8L for a 3.4L at the same time if it's a "just because" sort of upgrade. Link to comment Share on other sites More sharing options...
Wiggilez Posted June 28, 2013 Author Share Posted June 28, 2013 Thanks, I'am not entirely sure what is has, I haven't taken a good look at it yet, but the trans has four foward gears plus OD, and I would like to have a five speed, but I'm not quiet ready to do all the work for an engine swap just yet. Link to comment Share on other sites More sharing options...
GirsMJ86 Posted June 28, 2013 Share Posted June 28, 2013 There was the AX4 4spd and the AX5 5spd, really though it was nothing more than an AX4 with OD 5th. The AX15 is the same way. The AX15 is normally swapped to because someone either has a 4spd, an auto, or a dying tranny and want the AX15 which is normally considered a stronger tranny. It is also swapped to if certain engine power conditions or off-road modifications are met since it is stronger. I believe the off-road aftermarket support is also better for the AX15. Link to comment Share on other sites More sharing options...
mvusse Posted June 28, 2013 Share Posted June 28, 2013 When going from an AX4 to an AX15 there is one problem, though: The 0.79 OD will be to steep to be usable with the stock 3.55 gears in the axles. Link to comment Share on other sites More sharing options...
Geonovast Posted June 28, 2013 Share Posted June 28, 2013 The AX-5's 5th isn't far off at 0.85, but the problem is really what 5th is geared at, but more that a 5th gear sucks with 3.55s and 2.5 or 2.8. I really wouldn't bother rigging up an AX-15 behind a 2.8 unless a motor swap was in the future or the trans was free. Link to comment Share on other sites More sharing options...
Eagle Posted June 28, 2013 Share Posted June 28, 2013 Thanks, I'am not entirely sure what is has, I haven't taken a good look at it yet, but the trans has four foward gears plus OD, and I would like to have a five speed, but I'm not quiet ready to do all the work for an engine swap just yet. ??? Four forward plus overdrive = five speed. The early XJ/MJ AX4 4-speed did not have overdive. Link to comment Share on other sites More sharing options...
Wiggilez Posted June 29, 2013 Author Share Posted June 29, 2013 like I said, I don't really which one I have, and the reason for wanting the AX-15 is that I do plan to later swap a 3.9 V6 out of a dakota in to it. those engines don't seem to big, so I'm it will go in easier then beating in a 4liter. Link to comment Share on other sites More sharing options...
Geonovast Posted June 29, 2013 Share Posted June 29, 2013 A 4.0 swap is going to be a lot easier than putting in a motor that didn't come in these trucks from the factory. Yes, early 86's needed a slight firewall mod, but it's not a big deal. A 4.0 swap can be done by grabbing an entire junked XJ that will give you literally everything you need except for the rear driveshaft... which you would need to deal with, regardless of what motor you're doing(except the ones that will let you keep the AX-4/5 in its present spot). Link to comment Share on other sites More sharing options...
Wiggilez Posted June 29, 2013 Author Share Posted June 29, 2013 oh, alright then, I'll keep a look out for one the seems in decent shape, I was just thinking of the 3.9 because it looked about the same size physically as the 2.8. Link to comment Share on other sites More sharing options...
GirsMJ86 Posted June 29, 2013 Share Posted June 29, 2013 The easy upgrade for a 2.8 equipped rig is a 3.4 swap since it is essentially the same block just better. You can use a lot of the 2.8 external accessories and it has the same bell housing pattern so the dakota ax15 will work. I personally though will be doing like geonovast said and just grabbing a complete xj to use as a donor. I'm going to grab the newest one I can find and swap everything. Not to hijack but question for geonovast. My rig is stock with an ax5, 3.55 gears, and the 2.8. I've not driven it yet with the clutch being out but will 5th really be that bad? Is it worth changing gearing? Link to comment Share on other sites More sharing options...
mvusse Posted June 29, 2013 Share Posted June 29, 2013 A 4.0 swap is going to be a lot easier than putting in a motor that didn't come in these trucks from the factory. Yes, early 86's needed a slight firewall mod, but it's not a big deal. A 4.0 swap can be done by grabbing an entire junked XJ that will give you literally everything you need except for the rear driveshaft... which you would need to deal with, regardless of what motor you're doing(except the ones that will let you keep the AX-4/5 in its present spot). He has the 2.8. The easiest swaps are a rear wheel drive Chevy 3.1 or 3.4, keeping all accessories and carburetor off his 2.8 Link to comment Share on other sites More sharing options...
Geonovast Posted June 29, 2013 Share Posted June 29, 2013 A 4.0 swap is going to be a lot easier than putting in a motor that didn't come in these trucks from the factory. Yes, early 86's needed a slight firewall mod, but it's not a big deal. A 4.0 swap can be done by grabbing an entire junked XJ that will give you literally everything you need except for the rear driveshaft... which you would need to deal with, regardless of what motor you're doing(except the ones that will let you keep the AX-4/5 in its present spot). He has the 2.8. The easiest swaps are a rear wheel drive Chevy 3.1 or 3.4, keeping all accessories and carburetor off his 2.8 You're right, I should have specified the motors that used the same block as the 2.8. Not to hijack but question for geonovast. My rig is stock with an ax5, 3.55 gears, and the 2.8. I've not driven it yet with the clutch being out but will 5th really be that bad? Is it worth changing gearing? I haven't personally driven a 2.8, but I had a 91 with an MPFI 2.5(more power than the 2.8) with 3.55s, and she did not like 5th on anything other than 70+ on a perfectly flat surface or downhill. I eventually just stopped using it altogether. Link to comment Share on other sites More sharing options...
mvusse Posted June 29, 2013 Share Posted June 29, 2013 I have a 2.5 with 3.55 axles and an AX5. At 55-60 mph I get the same mileage in 4th as I do in 5th, but at 75 I get 19 mpg in 4th, and 24 mpg in 5th. 5th is absolutely gutless, but the hills aren't very steep here, so I usually use 5th when going 65 or faster. Mind you, 5th gear in an AX5 is 0.85 to 10, where in an AX15 it is 0.79 to 1, so final drive ration with an AX5 in 5th gear with 3.55 axles is about the same as 5th gear in an AX15 with 3.73 axles. 0.79 overdrive behind a 2.8 with 3.55 axles would probably be all but useless. With a 3.1 or 3.4 it would probably work. A 4.0 with the AX15 would have had 3.07 axles from the factory, which I believe is too low, evidenced by better fuel economy at 70mph than at 60. At least in a 94 XJ I used to have. Never had it long enough to go a meaningful distance at 60mph in 4th gear to see if it was any better. Link to comment Share on other sites More sharing options...
Wiggilez Posted June 30, 2013 Author Share Posted June 30, 2013 thanks for the help everyone, I'd prefer a 4L over the 3.4L as it sounds that it has carburettor, and if and when I do an engine swap I'd like it to be EFI. Link to comment Share on other sites More sharing options...
GirsMJ86 Posted June 30, 2013 Share Posted June 30, 2013 Actually there are aftermarket EFI kits for the 2.8 and those bolt right onto the 3.4 as well or you could grab a stock EFI 3.4 and wire up the entire system. Link to comment Share on other sites More sharing options...
Wiggilez Posted July 1, 2013 Author Share Posted July 1, 2013 does the 3.4 actually put out a decent amount of power compared to the 2.8? Link to comment Share on other sites More sharing options...
GirsMJ86 Posted July 1, 2013 Share Posted July 1, 2013 The 3.4 is better than the 2.8 in basically every aspect. It was found in the monte carlo, camaro, firebird, and I'm sure several others. Just look it up on the wiki and you'll see. Much better aftermarket support too than the 2.8 and it was offered supercharged I believe, but don't quote me on that. Link to comment Share on other sites More sharing options...
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