How much should I expect to pay?

[Effeckt]

Getting ready to throw a 700R4 in my K5 and wanted to know a rough estimate of what I should expect pay a shop to do it for me. I have a turbo350 right now so I know the drive shaft has to be shortened etc. just wanted to make sure I don't over pay for the work.
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[BBrendal]

More then it is worth. I was going to do that as well but the trans guy said it wouldnt be worth the 3 grand plus to gain 2 to 3 MPGs. If you want to get better gas mileage I would do an LS swap with the OD trans or just leave it as is. Just my opinion.

[bk2life]

If you can remove your 350 and put your 700 in yourself you are saving all that labor. That is all you’re paying for is labor. It’s a weekend job in your driveway. Shorten your driveline could be around 100 bucks depending on your area. If you are not mechanically able to do the work, find someone who can, because a shop will charge you way too much in labor for a relatively easy job.

[Effeckt]

Well I have been wanting to do it mainly for the overdrive for highway driving. On top of that, my 350 needs to be rebuilt anyway (seals, etc are junk) and thus is prompting this even sooner. The added gas mileage would only be a perk. If I was worried about that the K5 wouldn't be here lol.
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[floyd]

Its not a cheap conversion there is alot of things that need to be done to put a 700r4 into a 4wd....

yes it bolts to your engine
tcase adapter usually is needed
both drivelines need to be lengthened/shortened
t case shift linkage will be 4"+ further back
transmission crossmember will need to be modified or moved
to get full benefit you need to find a way to lock up the torque converter

Is it worth it?

I recently built a big block 70 chevelle with 3.73s and a 4l60/700r4 and wish more of my classic fleet had OD trannys...the chevelle gets driven way more often because is isnt spinning a ton of rpm's just to go down the freeway....

[Firebirdjones]

The cheaper way to install one in these 4x4's is to simply move the engine forward the required 1.5" rather than moving the transfer case.

If you move the T-case back, you will need to have both driveshafts worked on (lengthened and shortened) and you will also run into shifter interfearance with the floor pan (and in my case the factory console). You can also run into exhaust issues (my case as well) because I run an H-pipe right behind the T-case that would have needed to be cut out and moved backwards. So I just opted to move the engine forward instead and it rid myself of all those issues and made the swap easier. Still a pricey proposition though, as you'll still need the adapter and output shaft setup to mate it to the T-case.


I was in the same boat, my turbo 350 was slipping. I drive mine daily and actually liked daily driving the 355/350 turbo combo, it was relatively economical considering (13 city and 16 highway). But I was now at a crossroads when the trans started acting up and knew I was keeping this thing and continue driving it so I gave a hard look at overdrives.

In the end, since I'm not a huge fan of the older cable operated 700's, I just decided to do the LS swap and go with a 4L60E overdrive like Brendal suggested above, and have the computer control the whole package. I now have tuning at my fingertips and get 17 city and 22 highway.

For me it had to be a long term commitment. If you don't plan to keep your blazer for at least several more years, I wouldn't bother with the swap.

[Effeckt]

Doing the LS/4l60e swap was what I wanted to do originally but is just out of my budget. I've been doing some digging around and came across some who went with a 200r4 as it is a direct fit. Any thoughts on that transmission or should I stick with a 700 if I go for the OD?
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[bk2life]

spend 400 bucks, get your 350 rebuilt, and put it back in. unless you drive your blazer alot it really doenst make up for the initial cash outlay.

[Firebirdjones]

The 2004R is an excellent trans that has proven itself behind 9 and 10 second Grand Nationals for many years now.

When built right they are stout, and I actually prefer them over a 700 any day of the week, with a better gear spread (less rpm drop from 1-2) and even more overdrive. (2.75 first gear and .67 OD).

I am unfamiliar with swapping them into a 4x4 application though. They have been swapped into just about any classic muscle car you can think of but I've never seen one in a 4x4.

Might want to check out Advance Adapters and see if they even offer an adapter kit for the 2004R to mate to the old transfer case before making any major decisions.

Then there is the cost of finding one and a rebuild to boot. So in the end I don't think it's any cheaper than going the 700 route, so it becomes personal preference at that point.

To build an overdrive trans right with good parts, plus the cost of a core trans if you don't have on already, a new converter (I never do a new trans and old converter), the adapter setup for the transfer case, and other misc...you can spend $1,000 easily and probably alot more to do a trans swap like this. Of course you can throw a bunch of used parts at it and save a few here and there if you wish. I prefer not to go that route as I like to do it once and done. It's all a matter of what you want to budget.

Like I mentioned though, if you don't plan to keep the blazer or are uncertain about it's future, this swap might not be worth while. There just really isn't an easy or cheap way to go overdrive in any classic vehicle in my experience. It's all a bit on the pricey side.

[Effeckt]

I am prepared to spend the money and have basically determined that this Blazer is with me for life. I sold my first one and regretted it ever since. So it is more about getting it enjoyable to drive the way I want to.

I was hoping I could have it all said and done for no more than $2k but obviously if I can get it less, then that is more I can put into fixing up other things. Like you, though, I am all for doing it right the first time and don't want to cut corners anywhere.

I think I will start by looking into what I can get a shop to quote me for the swap and go from there. I plan to someday take the K5 on short road trips with the family and having the OD would be really nice.
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[Firebirdjones]

That's great. Sounds like the overdrive would be a perfect match and suit you well.

I would tend to believe you could do it for under $2000 but I suppose that would depend on several things. I spent about $1300 on my 4L60 to build it stout and support up to 600hp just for piece of mind, but they can definately be built cheaper. The adapter setup on top of that, then I did the install myself.

I think what is really going to vary alot in cost is paying someone labor to install it, if that is what you are looking to do.

[IwantaK5]

I recently put a 700r4 in my blazer. I got the advanced adapter output shaft to fit with the np205 and had the transmission rebuilt using the adapter. cost my around $1,200, for adapter and rebuild. I also got the B&M lock out controller for the transmission. I moved the engine forward rather than moving the transmission back so i was able to use all the factory driveshafts. Make sure you use the stock 700r4 oil pan, because i used a bigger finned aluminum pan and the front driveshaft wont work with it. I would say the 700r4 is worth it over the th350. They only thing i would swap the 700r4 for is a NV4500. I miss not having a manual.