RT4wd, 2wd rear crossmembers interchange.

I apologize if this has been covered before- I couldn't find it.

Here's the question:

Will the rear suspension crossmember from a '90 DX 2wd fit an '88 RT4wd car?

Answer: Yes, it will with minor modification. Here's a before picture

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and the 2wd donor car

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after removing the crossmember, had to use this allthread to tie the lower control arms together (just to roll it around the yard)

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It's easy to remove, just the 2 inner LCA bolts and 4 bolts into the 'frame'. This one decided not to cooperate. I never did get it out. This corner is now welded to the car :P

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member removed

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There are some differences in form, but all the critical points line up

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Just drill out the spotwelds and remove the differential mount bracket to reuse on your new crossmember

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clean up the area to be welded, then bolt it all up in place before tack-welding the mount

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take it back down and plug-weld where the old welds were drilled. I added a couple of tacks.

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Then just rattlecan the bare areas or undercoat to prevent rust formation, you're all set!

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Comments

  • Hi,

    I don't think so. They differ by an inch orso...
    Did you anticipate a mod...

    just asking...

    no?



    :mrgreen:
  • They are completely interchangeable, except of course for the mount for the rear diff. That is the only difference. That flate plate with 3 threaded bolt holes that holds the rear diff mount will have to be "swapped" over.

    I bolted the 4WD rear subframe into my FWD car, no problemo!
  • bam-bambam-bam Council Member
    Very cool, thanks! I haven't seen it yet, but it sounds like it's creased where the LCA bolts up.
  • bam-bambam-bam Council Member
    I guess I'll know for sure very soon! He's on the way over here.
  • I guess I'll know for sure very soon! He's on the way over here.
    static !



    :mrgreen:

    btw... I have/found something RT4wd for you...
  • bam-bambam-bam Council Member
    edited first post with how-to instructions. enjoy.
  • Thanks so much !

    So do the trailing arms bolt across as well ?

    I'd always thought that a 2WD couldn't be converted. But it seems of late that isn't the case.
    over here the 2WD's have always seemed to be in better condition. Getting a mint one of those and converting it to 4WD can be easier than trying to dothe bodywork!
  • bam-bambam-bam Council Member
    Yes, I'm sure the trailing arms will swap over as well. I don't see any reason why a 2wd can't be converted...give me the 2 cars and about a week or so.
  • My FWD 91 Wagon is about 95% done. I'm not doing 4WD. I'm in fact headed 100% the other way from FWD!
  • Had a pal check his sedan over here. That subframe isn't removable so suggests the 4WD sedan might be using the shuttle floor plan rather than the sedan one. He did however say something about frame rails being way hte hell back but it didn't make sense.
    I wondered if there are mounting points on the sedan for the shuttle style x member and they just don't weld the normal one in place for a 4WD.

    Now looking for mint condition 2 WD's are well :)
  • rezistk20rezistk20 New Wagonist
    hmm gotta find me a all wheel drive or rear wheel drive will do for the sands?
  • curtcurt Wagonist
    so the 88 rt4wd rlca bolted up to the 90 fwd rear subframe with no problems?
  • bam-bambam-bam Council Member
    curt wrote:
    so the 88 rt4wd rlca bolted up to the 90 fwd rear subframe with no problems?

    yes, it did.
  • skinnyskinny Senior Wagonist
    While it was out you should have cleaned it up and put some rust proofer on it.
  • What is the advantage of replacing the AWD cross-member with the 2WD?
  • wes wagon wrote:
    What is the advantage of replacing the AWD cross-member with the 2WD?

    Probably because the 2wd one is easier to find in the off chance your RT one is rusted out.
  • Probably because the 2wd one is easier to find in the off chance your RT one is rusted out.
    I hear ya. I didn't think there would be any sort of performance advantage or anything like that.
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