I am in the process of compiling the parts to do dual cases for my 87 p/u. I'm familiar with the fact that you need the rear case to be a top shift tcase. The tranny and tcase is from an 84 with the forward shift tcase and I bought a top shift tcase out of an 89 4cyl. My question is since I know the top shift case is good should I just bolt it up to the adapter or does it need to come apart for any other reason before install?

 

Build dual cases...once. Don't build them then add 4.7 gears, then twin stick, then chromoly output shaft, then chromoly front output shaft etc

Your crawl box, front part tcase that attaches to tranny will have to be forward shift. Then your dual case adapter, then your top shift case.

Save your pennies and do it all at once and tear it apart once.
I rebuilt mine where needed if any seals or bearings looked bad.

:wabbit2:

 

I agree with Wabbit, I just did 4.7 gears in a single case and I want to go duals in the future, now after all that hard work, I wished I would have had the money to do it all at once and get the 23 spline input for the rear case.

 

Though I'm building on a tight budget, you guys are right. I will tear both down to see if anything needs replacing. I will put the 23 spline shaft in, but can't really afford the 4.7 gears. I tossed up either going single 4.7 or dual 2.28's, and decided from reading others comments etc. that the duals would be better off, and better suit my needs. I know the adapter is a little less than the 4.7 kit, but I still have to get my shafts modified and buy a dual case skidplate. Anymore than that will anger the Queen .

Oh yeah Wabbit, I just bought the rear spring hanger kit from you a couple of weeks back for my 63" Chevies. Can't wait to tear into them.

 

I disagree. The advantages of dual cases are huge. Do the build as you can afford.

Tearing apart tcases is very quick, and very easy. Once you've done it twice or so, it takes only a couple hours to get it in, modified, and out. Doing 4.7's will take longer, but I've had my cases out at least once a year since I got them.

 

I agree - you don't need 4.7 gears, twin stick, and chromoly shafts.

Most of us are budget wheelers these days... I'd rather be out wheeling with stock dual cases then saving money more months\years to all the bling that you can eventually add at any time.

That being said I've been running stock dual cases (stock geared + 21 spline) for over 5 years on 37's and I'll continue to do so.

I would just bolt to good top shift case the adapter and then replace the output flange seal.

 

thanks guys. I'm gathering the parts for the cases now. Just got a top shift tcase for $25 on craigslist. looking for a used adapter or a new one from a project that never got off the ground. If you know of one let me know.