72 K5 Blazer Transmission & Transfer case

[tismy55]

What newer year Transmission & Transfer case will fit my V8 72 K5 Blazer?

[truckster]

What is it you're trying to accomplish? Are you looking for automatic or manual?

There are a number of options, but most, if not all, require some modifications.

[1972K20]

The most common autos are TH350 and 700R4
For manual, after the SM465, I is the NV3500 or NV4500.
Transfer cases are NP203 and NP208, NP241 (most NP241 are passenger side drop)

[tismy55]

I purchased a 72 K5 blazer without an engine ,Transmission Or transfer case, I was needing the transmission & Transfer case I can't find one for the 72 So i thought a newer one would be easier to find. I'm looking for Automatic Transmission & transfer case I just don't know what year will fit.

[RED 1970]

Stock is a TH350/NP205 combo. These aren't impossible to find. You can buy them new too for probably $2,500.
Do you have the cross member?

Later K5’s came with TH350/NP203’s, you probably don’t want one of these full time cases.

Next came the TH700R4/NP208 combo. You will get an overdrive and the t-case is much lighter. These should be plentiful.

If you want a little bit of beef you can get a TH400/NP208 combo out of a later ¾ ton suburban.

The later K5’s used the 700/NP241 combo…

The good thing about Chevy’s is just about anything will bolt to anything with the correct adapter.

[tismy55]

will these bolt up to the stock crossmember ? And if i decide to go 700 R4/np208 what adapter do i need and where can I buy the adapter ? Thanks for the help

[1972K20]

Check with Advance Adapters.

http://www.advanceadapters.com/

[RED 1970]

If you go with a 700R4/208 you don't need an adapter, you need a new cross member.

700r4 will bolt directly to your block with no issues.

[1972K20]

That's correct. I wasn't thinking when I replied.

However, driveshafts may need to be modified.
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[tismy55]

I found a 700R4/NP208 with crossmember and Both Driveshafts for $500 is that a good price to pay It was rebuilt last year.

[RED 1970]

Depending on what it came out of you may or may not have to have the drive shafts re tubed to get them to the correct length.

cross member may need to be modified too, I think the frame rails are a few inches narrower than the 73-91 rigs. assuming the combo came out of a blazer.

Either way $500 is pretty cheap for a trans/t-case that were just rebuilt a year ago. Find out if it was done by a shop or by the seller in his garage.

[tismy55]

It came out of a 78 Blazer and was rebuilt at a local Transmission & gear shop. What kind of modification will i need to do to make the 700 R4 crossmember work on my 72 .Thanks

[RED 1970]

Just so you know the 700R4 wasn't available in a K5 until 1982. The earlier versions had issues and are not desirable.

Originally Posted by tismy55

What kind of modification will i need to do to make the 700 R4 crossmember work on my 72 .

Can you cut, weld, grind and drill metal? If so you're good. If not you need to learn.

[tismy55]

what is the earlier versions can you give me a year so I can stay away from them. Thanks

[tismy55]

I talked with the owner It came out of his 85 Blazer Not 78 My bad.

[RED 1970]

I think pre-86. Since you are looking at a transmission that came out of a 78 K5 (which was not stock) you will have a hard time figuring out what year transmission it is.

[tismy55]

Red 1970,,It is a 85 model should i keep looking Or what would you do.I don't want to buy anything that will be trouble down the road.Thanks for your help in this matter.

[RED 1970]

Ask the shop that rebuilt it. I think the issue is with the sun gear? I know enough to point you in the right direction but not enough to really give you a definite answer, sorry.

The issue would really present itself if you are going to wheel your rig or drive in an abusive manner, including on towing heavy loads. If you're just cruising like I do with my 70 they you might be fine. I don't want to scare you and tell you that it will blow up as soon as you touch the gas but to make you aware there is a difference.

[tismy55]

Ok I appreciate it for the type driving I will be doing it should be fine. I will just be crusing down the freeway not much off roading. no towing

[tismy55]

question ,when modifing the crossmember to fit my 72 frame what pinion angle should the transmission to rear end be at .Thanks

[tismy55]

I found a 1989 K1500 The guy doesn't know what transfer case it is ,he does know the transmission is a 700R ,,Anyone know what transfer case were used in the 89 chevy K1500 Thanks

[RED 1970]

The trucks changed in 88 to an IFS front suspension, I think the transfer case drop will be on the wrong side, driver vs. passenger side.

[tismy55]

Ok Thanks for that info. when Hooking up the front drive shaft does it need to be parallel to the ground.when I weld the crossmember in? Thanks