Tranny Swap

[Deltawhiskey]

I asked earlier if its possible to swap a 2003 wrangler tranny into an 88 YJ. So far everybody said they saw no problem with it. But i have another question about this. This tranny I'm thinking about swapping is out of a 2.4L. If this thing goes into my 258ci is this tranny going to be able to handle the engine and not blow apart? Also I just replaced my clutch and the slave cylinder last dec in my 88YJ. And now I think that slave cylinder went out. Has anyone else ran into this problem?

[Deltawhiskey]

Also i heard a loud grinding sound like a bearing going out. I never replaced my throwout bearing when i replaced my clutch. Could this have any thing to make the slave cylinder go out and could this be this shrill I kept hearing for 4 days?

[zachv]

I would think the 2.4 trans would not fit the old 258. Maybe people were thinking you had a 6cyl trans.

[edudley]

I am confused here. The slave cylinder and through out bearing are one in the same aprt in an 88 YJ. These platic internal slave cylinders are not very dependable. I agree with Zach as to the engine difference.

[Tim Comer]

If the tranny out of the ’03 is a NV 3550, Advanced Adapters makes a conversion bellhousing for this swap. If you can, grab the transfercase also. I keep thinking the input shafts on the two transfercases are different. That’s if you have the NP 231. Externally they are the same. Not cheap, but AA will be able to tell you about all the components needed to make this work. Tranny swaps are never cheap or easy.

[matts88yj]

I am going to swap a NV3550 in soon. Tim is dead on right, Advanced Adapters has everything you need for the swap. There is a difference in the gears from the tranny to the t-case. The NV3550 has 23 splines while your current MAY only have 21 splines. I would just double check to make sure that the splines are the same or different. If you need any help or info let me know as I have some now and will have a lot after the swap. HTH!!!

Matt

[Deltawhiskey]

When i get the tranny its going be everything from the bellhousing, drive shafts, and the tc. I figured this would alleviate any unseen problems that i may encounter. Any body have input if the tranny will hold up if indeed they match up? Thank for the help everybody.

[Tim Comer]

I’m thinking the 2.4 has a Mopar bolt pattern and the bellhousing won’t bolt to the 258. You would need a bellhousing from a 4.0 as that has the old AMC bolt pattern and will bolt to your engine. Also, your YJ has the internal hydraulic throw out bearing. I’d ditch that if I could. Swapping the hydraulic clutch components around is not in my knowledge base. Someone else that has done this would have to chime in. The NV 3550 is a good tranny. MUCH stronger than the Peugeot. It’s not indestructible mind you. With a high torque engine and locked at both ends, it will go bad.

[ChadYJ92]

My roommate is running an NV3550 behind a built 350 in his CJ. If it can handle that kind of power (it puts out roughly 345 lb/ft), it will handle the 258 with ease. I really don't think that you need to go through AA. I found that their prices are incredibly expensive, and I was able to find other ways to do my tranny swap for cheaper. The only part I purchased from them was my CPS relocation kit, but if you get a TJ bellhousing, it should already have a place for that sensor. For the record, I converted mine from an auto to manual for roughly $1000, so aside from the differing costs of our trannys (mine was $200 w/ clutch linkage and yours will probably be $800 or more) you shouldn't spend all that much more than I did. If your NP231 is a 21 spline unit, let me know. I think that I still have a bunch of NP231 parts lying around in my basement, I might have a 23 spline input shaft for you.

I'm also curious to know if you are lifted or not? I ask because if you are, it might be a good time to get a SYE if you don't already have one. That would save you from buying the standard driveshaft, and then later paying for a CV shaft.

[ChadYJ92]

Originally posted by Tim Comer:
Also, your YJ has the internal hydraulic throw out bearing. I’d ditch that if I could. Swapping the hydraulic clutch components around is not in my knowledge base. Someone else that has done this would have to chime in. If anyone wants to know how to swap in a manual linkage set-up, I can give advice. And I've never actually converted from an internal to external, but I can't imagine it being all that difficult.

[kwrangln]

There were a couple tranny's available behind the 2.4L 4 bangers, the NV1500 (also called the NV2550 aultho its the same tranny) or the NSG370 tranny. The 1500 was the 5 speed that was later replaced by the 370 which is the 6 speed.

Jeep saw the wisdom of using a larger tranny with more torque capacity behind its 6 cyl engines, they did this for a reason. Putting a 4 banger tranny behind your 258 is going to be a mistake as you will probably end up with just as many if not more problems than you have with your current Pugeot tranny.

Look to the 6 cyl jeeps or step up to a NV 4500 if you want to also improve your off road capability. The NV 3550 would serve you well but lacks the granny gear of the 4500. I'll have to check when I get time to see availability on bellhousings to go from the Mopar tranny case pattern to your 258 block as all the research I've done was to put the 6 cyl tranny behind the 4 banger of my last heep. Havn't looked at adapting anything to the 258 since mine already has the 700R4 auto in it.