Can a TJ VIN be used on TJ Unlimited build?

myjeep3

myjeep3

TJ Enthusiast
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Jul 4, 2019
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Building a TJ Unlimited from sourcing frame and tub separately, and other piece separately, and have a 98 TJ Complete to use for parts. Will use Axles, suspension, trans+Tcase, etc.
Can I use the TJ vin on the Unlimited? I will be using the trans from the TJ with a LS motor, so though it would be easier to retain the TJ computer and harness to run the trans and tcase.
 
The VIN answer here is almost certainly going to vary across states.

But you're going to LS swap and retain the 32RH? Is that the common way to do that swap? I assumed a GM trans was used in an LS swap.
 
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hear said:
The VIN answer here is almost certainly going to vary across states.

But you're going to LS swap and retain the 32RH? Is that the common way to do that swap? I assumed a GM trans was used in an LS swap.
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The TJ has the AX15, will retain that and the Tcase
 
hear said:
The VIN answer here is almost certainly going to vary across states.

But you're going to LS swap and retain the 32RH? Is that the common way to do that swap? I assumed a GM trans was used in an LS swap.
Click to expand...

You can adapt pretty much whatever you want. The 32RH if I remember correctly is rated for 300 Ft-Lb of continuous torque. Plenty good for a stock 4.8/5.3 LS.
 
myjeep3 said:
The TJ has the AX15, will retain that and the Tcase
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Well then the computer isn't going to have any bearing on the transmission. It only barley interacts with the auto. The t-case sends the speedo output to the computer, and I think the 4WD light on the instrument cluster also goes through the computer (need to double check on that).
 
hear said:
Well then the computer isn't going to have any bearing on the transmission. It only barley interacts with the auto. The t-case sends the speedo output to the computer, and I think the 4WD light on the instrument cluster also goes through the computer (need to double check on that).
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?? Didn't get you. I will be using the tj computer with trans and tcase.
 
hear said:
Well then the computer isn't going to have any bearing on the transmission. It only barley interacts with the auto. The t-case sends the speedo output to the computer, and I think the 4WD light on the instrument cluster also goes through the computer (need to double check on that).
Click to expand...

Yes but an Unlimited PCM will either be looking for a 42rle or at very least a crankshaft sensor in the nsg370 location, requiring him to buy a $500 Bell housing.


I don't know the legalities but since the main VIN label is on the tub I would think you'd have to go with that. However, my understanding is that you can change the VIN in the PCM to match your tub if that's something of concern to you.

There may also be emissions considerations depending on your state. Not sure how they like seeing an older ECU in a newer vehicle, kinda like how engine swaps have to be newer than the vehicle they go into.
 
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freedom_in_4low said:
Yes but an Unlimited PCM will either be looking for a 42rle or at very least a crankshaft sensor in the nsg370 location, requiring him to buy a $500 Bell housing.


I don't know the legalities but since the main VIN label is on the tub I would think you'd have to go with that. However, my understanding is that you can change the VIN in the PCM to match your tub if that's something of concern to you.

There may also be emissions considerations depending on your state. Not sure how they like seeing an older ECU in a newer vehicle, kinda like how engine swaps have to be newer than the vehicle they go into.
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I will not be using the Unlimited PCM, basically just the tub, and frame. I will retain the TJ PCM, AX15, Tcase, Axles etc.
In the state of MA, no emission is require if vehicle is over 10yrs old, so no issues there.
 
freedom_in_4low said:
Yes but an Unlimited PCM will either be looking for a 42rle or at very least a crankshaft sensor in the nsg370 location, requiring him to buy a $500 Bell housing.
Click to expand...
I assumed the LS swap had it's own way of handing cam/crank timing, but he said he was planning to use the PCM off the 98 so the shift control etc won't be a factor. Upon re-reading, it's not clear which computer he was going to retain. I quit. :)
 
myjeep3 said:
I will not be using the Unlimited PCM, basically just the tub, and frame. I will retain the TJ PCM, AX15, Tcase, Axles etc.
In the state of MA, no emission is require if vehicle is over 10yrs old, so no issues there.
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If using a manual trans with an LS, why even bother with the PCM? that would be excess wiring and equipment to take up weight and space... I'd say gut the whole body harness, go with a painless or similar harness, and new guages.

For your thread questions though, you may want to see about a new VIN through the state... you'll need to keep receipts, bill of sale, etc records to prove ownership of the parts, but they should be able to inspect and issue a homebuilt or hot rod type ID number. You will need to either have a matching VIN on both the body, and the frame, or make sure you are fully documented for that as well... New VIN would be the most legal way to do it.
 
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Artsifrtsi said:
If using a manual trans with an LS, why even bother with the PCM? that would be excess wiring and equipment to take up weight and space... I'd say gut the whole body harness, go with a painless or similar harness, and new guages.

For your thread questions though, you may want to see about a new VIN through the state... you'll need to keep receipts, bill of sale, etc records to prove ownership of the parts, but they should be able to inspect and issue a homebuilt or hot rod type ID number. You will need to either have a matching VIN on both the body, and the frame, or make sure you are fully documented for that as well... New VIN would be the most legal way to do it.
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Still need the Jeep PCM to run the transmission.
Prove ownership of parts??? why??
No VIN on frame, and the Tub vin is on the dash dash upper corner, so I can always retain the dash of the TJ. When scanning the computer for inspection, it will come as 98 TJ, thats all. So basically it will be a TJ with and unlimited body, and People do that conversion by cutting the tub/frame and extend it. So no difference with what am trying to do.
 
myjeep3 said:
Building a TJ Unlimited from sourcing frame and tub separately, and other piece separately, and have a 98 TJ Complete to use for parts. Will use Axles, suspension, trans+Tcase, etc.
Can I use the TJ vin on the Unlimited? I will be using the trans from the TJ with a LS motor, so though it would be easier to retain the TJ computer and harness to run the trans and tcase.
Click to expand...

1) if the frame and tub are from the lj then you'll want to use the lj vin to avoid a reconstructed title. Swapping vins is illegal and you're putting yourself at the mercy of whatever law enforcement ever runs your tags and knows the difference between a tj and lj.

2) the trans and tcase don't need a computer at all. The pcm would only be for running your stock dash. The LS will be run by a gm computer. Even here in smog nazi CA i don't need my vin to match the pcm vin. Your results may vary.

3) the only way i would feel comfortable registering it as a 98 would be to stretch the 98 frame(without disturbing its vin)and only use the lj tub.i would put the 98 dash shell with its vin on it
 
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Rickyd said:
1) if the frame and tub are from the lj then you'll want to use the lj vin to avoid a reconstructed title. Swapping vins is illegal and you're putting yourself at the mercy of whatever law enforcement ever runs your tags and knows the difference between a tj and lj.

2) the trans and tcase don't need a computer at all. The pcm would only be for running your stock dash. The LS will be run by a gm computer. Even here in smog nazi CA i don't need my vin to match the pcm vin. Your results may vary.

3) the only way i would feel comfortable registering it as a 98 would be to stretch the 98 frame(without disturbing its vin)and only use the lj tub.i would put the 98 dash shell with its vin on it
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So…how about when I do a frame swap and the vin stamped in the frame doesn’t match the dash plaque? The new fenders I got have a vin sticker on them…that won’t match the dash. Are they illegal too?
 
Mike_H said:
So…how about when I do a frame swap and the vin stamped in the frame doesn’t match the dash plaque? The new fenders I got have a vin sticker on them…that won’t match the dash. Are they illegal too?
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I wouldn't worry about fenders mike. But technically when you have different frame and main body vins there should be some kind of proof of ownership trail and documentation in your motor vehicle dept(aka reconstructed title). The reason for these laws is to stop chop shop stolen cars from being resold.

Like i said,it puts you at the mercy of law enforcement. I wouldn't want to lose my jeep because i couldn't prove i own half of it and had the right to play mix and match.

Even if you are an upstanding citizen you could wind up at a park that just had kids causing trouble right before you got there. Several times I've had angry park rangers roust me over other peoples poaching or destruction of public property.
 
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