Opinions/advice needed on my 4x4 conversion

[clarkerussell]

OK, now that I have a used BA10 to swap into my Comanche I have bought (literally) some time to assemble the right parts for my 4x4 conversion. Before I go crazy and start buying things that won't work together, I have to start with some questions:

 

1) I've been told by a guy on eBay that sells complete BA10 to AX15 conversion kits that the bellhousing that I have now (with my BA10) is NOT compatible with an AX15. Everyone here says it is compatible. I trust the opinions here more than the eBay seller, but I just need to be certain. Is the Bell housing from a 1988 4.0L, 4x2, BA10 tranny 100% compatible with the AX15?

 

2) Since I'm looking for donor cars, should I broaden my search to include the newer NV3550 5 speed tranny's, or is that too much of a hassle for my stock 4.0L engine? What's the advantage to the the newer NV3550?

 

3) Am I giving up anything with using the NP242 over the NP231? I really like the idea of having full time 4WD for non off road use (snow, etc).

 

4) Is there a special front end that I should be looking for, or are they all pretty much the same (gearing, options, etc)? I hear the rear end is a whole other topic... I'll deal with that shortly.

 

Thanks in advance everyone.

[mjeff87]

Usually, tranny's are sold with the bellhousing/clutch cover included. I'd look for an AX15 (complete) with an external slave cylinder and just swap it in whole.

 

An NV3550 is going to be harder to find (and comparably more expensive) than an AX15, because it is more late model.

 

The 242 never came behind any manual tranny stock, but that doesn't mean it won't work....it'll bolt up directly. Just pay attention to the input spline count and length. Some say it's a weaker case than the 231, but depending on what you plan to do with it I'd say the FT option is a fair trade-off.

 

An XJ/MJ D30 bolts in directly (read: easily and cheaply), and is adequate for most applications.....

 

Jeff

[Pete M]

The Peugeot bellhousing will NOT bolt to the AX-15. You must get a bellhousing with the AX-15.

 

The NV series transmissions are stronger and better then the AX-15, but as he said, they are newer and will cost more. Stay away from YJ/TJ transmissions if you want a bolt-in experience. They are a bit different than XJ/MJ transmissions.

 

The 242 is supposedly not quite as strong as the 231, but that only comes into play if you're truly abusive when wheeling or running really big tires.

[clarkerussell]

The Peugeot bellhousing will NOT bolt to the AX-15. You must get a bellhousing with the AX-15.

 

The NV series transmissions are stronger and better then the AX-15, but as he said, they are newer and will cost more. Stay away from YJ/TJ transmissions if you want a bolt-in experience. They are a bit different than XJ/MJ transmissions.

 

The 242 is supposedly not quite as strong as the 231, but that only comes into play if you're truly abusive when wheeling or running really big tires.

 

Is the NV3550 bellhousing compatible with the 1988 4.0L engine? In other words, if I decide to source an NV3550 and I get the tranny and bellhousing, will it bolt to my engine, or do I need to get an AX15 Bellhousing and the NV3550? Thanks.

 

Clarke

[Pete M]

The bellhousing on the 3550 is integrated, meaning that it doesn't remove from the trans.

[DirtyComanche]

But to answer your question, the NV3550 will bolt right up to a 4.0.

 

 

I think you need to fiddle with the pilot bearing like with the AX-15 swap.

[clarkerussell]

But to answer your question, the NV3550 will bolt right up to a 4.0.

 

 

I think you need to fiddle with the pilot bearing like with the AX-15 swap.

 

Cool, I found an NV3550 for $600 with 57K miles on it. I think I'll go that route. Now I just need to find an NP242, front axle/drive shaft, etc.

 

Speaking of the front axle/drive shaft, does anyone know if the front shaft if different between the NP242 and the NP231? Thanks.

 

Clarke

[Pete M]

The front shaft ahould be the same for the 242 and 231, but it is a bit different from manual trans to auto trans.

Did this 3550 come from a TJ or XJ?

[clarkerussell]

The front shaft ahould be the same for the 242 and 231, but it is a bit different from manual trans to auto trans.

Did this 3550 come from a TJ or XJ?

 

Supposedly it's from a 2001 XJ. Would the front axle from this jeep work in my 1988 Comanche?

[Pete M]

Yes, but it'd be low pinion.

[jage]

I know you probably don't want a 249 but I've got one I want to get rid of.

[clarkerussell]

OK, so it looks like if I get the NV3550 (23 Spline) and a post 1991 NP242 (23 spline), I should be good for the tranny/transfer part of my conversion.

 

Now, since I'm putting this in my 1988 4x2 Comanche, I will need to shorten the drive shaft. Is that the only other thing that I'll need to do right away? Are there any other "Gotcha's"?

 

I'm planning on adding the front axle shortly, but I have to get my truck on the road ASAP... Thanks.

[mjeff87]

got new clutch stuff? You'd be foolish to not replace it if it needs it.

 

DON'T have the flywheel resurfaced.

 

Replace all the UJ's in both driveshafts (not essential, but again it's a perfect time). They don't like changes in operating angles.

 

Jeff

[pingpong]

I would be looking at different front axles then the stock d30. Also it isnt that much more work to swap in the stronger NV4500. Its all about choices.

 

As for the Np242. It is a fine t-case as long as you don't mind the lack of SYE choices. Supposedly itis just as strong as the np231, just the aftermarket supportr isnt there.

 

Persoannly my choice would be a NP435, and a 2o3/205 doubler behind it :wrench: it might take a lil more work, but with a crawl ratio somewhere around 100 to 1.. it would be all good :cheers:

[whowey]

I know you probably don't want a 249 but I've got one I want to get rid of.

 

Does that include the bad Viscous Coupler 'conversion kit'?

:cheers:

[clarkerussell]

got new clutch stuff? You'd be foolish to not replace it if it needs it.

 

DON'T have the flywheel resurfaced.

 

Replace all the UJ's in both driveshafts (not essential, but again it's a perfect time). They don't like changes in operating angles.

 

Jeff

 

I have a new clutch, but it's for my old BA10... Do you know if the clutch and pressure plate are the same? If not, what clutch would I need to get? Would I need one from a newer XJ that the NV3550 came from? Thanks.

 

Clarke

[clarkerussell]

I would be looking at different front axles then the stock d30. Also it isnt that much more work to swap in the stronger NV4500. Its all about choices.

 

As for the Np242. It is a fine t-case as long as you don't mind the lack of SYE choices. Supposedly itis just as strong as the np231, just the aftermarket supportr isnt there.

 

Persoannly my choice would be a NP435, and a 2o3/205 doubler behind it :wrench: it might take a lil more work, but with a crawl ratio somewhere around 100 to 1.. it would be all good :cheers:

 

Well, since I'm not going to be doing any serious off roading, I think the NV3550 and NP242 should be fine... I just want a good 4x4 truck for use in bad weather and the occasional trip down a bad road... Besides, I can get an NV3550 for about $550 and the NP242 for about $275... I think this is a pretty good price, but I could be wrong...

[clarkerussell]

got new clutch stuff? You'd be foolish to not replace it if it needs it.

 

DON'T have the flywheel resurfaced.

 

Replace all the UJ's in both driveshafts (not essential, but again it's a perfect time). They don't like changes in operating angles.

 

Jeff

 

By the way... why wouldn't you want to resurface the fly wheel?

[mjeff87]

got new clutch stuff? You'd be foolish to not replace it if it needs it.

 

DON'T have the flywheel resurfaced.

 

Replace all the UJ's in both driveshafts (not essential, but again it's a perfect time). They don't like changes in operating angles.

 

Jeff

 

I have a new clutch, but it's for my old BA10... Do you know if the clutch and pressure plate are the same? If not, what clutch would I need to get? Would I need one from a newer XJ that the NV3550 came from? Thanks.

 

Clarke

 

I don't know for sure. Physically they're likely to be the same size (9.75" or so), but the input spline count may be different between the cases. Try calling the dealership, or check an auto parts store to see if the part #'s are the same.

[mjeff87]

got new clutch stuff? You'd be foolish to not replace it if it needs it.

 

DON'T have the flywheel resurfaced.

 

Replace all the UJ's in both driveshafts (not essential, but again it's a perfect time). They don't like changes in operating angles.

 

Jeff

 

By the way... why wouldn't you want to resurface the fly wheel?

 

AX15's in particular have a specially shaped 'wheel...it's concave rather than flat. Machining it will remove the concavity (is that even a word? :D ). Also, internal slave/throwouts are very sensitive to changes in clearance between the clutch disc and flywheel....if you do machine it, you should shim out the throwout the same amount as what was machined off the 'wheel.

 

All that being said....I machined my flywheel on my AX5 and didn't have any problems. Cmcolfax machined his and we tried installing an AX5 in place of a dead auto in his YJ and we're having problems with it. Basically, it don't work :headpop:

 

Best bet, if the flywheel is bad enough that it needs to be machined, and you can spare the cabbage, you're better off replacing it.

 

Jeff