I boughta 97 Suburban for 800 dollars. 140,000 miles 4x4, 5.7l

My 88 K5 needs a trans and Im trying to sort out how to swap the engine, trans, and transfer case into my K5 from the Suburban. Few things I cant find answers to.

Yokes? Will my tokes fit the push button 4x4 case, or can I swap my transfer case to the 4L60E from the Suburban?

Security? Is the security system going to give me problems. I was hoping the BCM body control module was seperate from the ECM wiring.

Gauges? Not sure what to do here for the gauges. The Suburbans will all be electronic, any thoughts?

General trans and transfer case fitment. Any thoughts on this in general? Cross member relocating will probably be mandatory but not a prob.


Thanks, Any input will be great.

 

In my opinion, it is not at all worth the trouble. #1 problem is that your 88 has the 700R4 transmission and the 97 has the 4L60E, "E" for electronic. You would have to do a complete swap over of all wiring, the engine, transmission, and transfer case to get everything to want to work together appropriately without spending tons of $$ on stand alone controllers.

Gauges would be another nightmare after the swap as you would have a fun time trying to swap over inside and outside wiring harnesses and then fitting the cluster into the dash of the 88 along with the 4wd switches (unless it is a manual shift transfer case)...

It is a lot of work. I am not saying that it is impossible, but I really question if it is worth it.

 

Not to mention that the front driveshaft output is on the wrong side. You are better off trading your parts for thatfrom a 87 through 91 blazer or suburban.

 

Ok guys so I thought hard and decided to sell the 97, I sold it for 1000.00 so I made 200.00 there.

Then on my way home I saw a 1990 Suburban with a plow for sale. It was almost completely rust free, and the interior was mint. Guy needed money and took 900 for it. Just sold the plow for 700 and the 31's off it for 400, the interior is going in my K5, and the whole front clip also. Then im gonna swap the 350TBI and TH400 over to the K5 also.

Heres the new question. 700R4 to TH400. What problems will I run into? Obviously I have everything from the suburban including longer driveshafts to shorten if needed.
Crossmember line up?
Keep the transfer case from the suburban or K5?
Yokes?
Driveshaft length?

Thanks for the help. Heres a pic of the truck. The plow was a 8ft Western and was mounted about 15" infront of the front bumper. It looked goofy, but hey it worked and sold lol...

 

The Suburban has a TH400? Are both t-cases NP208s? Or does the suburban have a NP241 t-case? The easiest thing to do would be to swap the tranny and t-case from the sub to the blazer. This should be a pretty straight forward swap. Then use the better of the two front drive shafts and the rear shaft from the blazer. Having the entire doner vehicle sure does make it nicer. Also - check the gear ratio of the sub axles. Could be the optional lower 3:73s which would be easy to swap into the blazer. Might also find a gov-loc in the rear. Sweet project.

 

Yea to my surprise it has a TH400, and from what I read it should be a 241 in the burban, and whatever stock is in my 88 K5 is still there. Im just trying to figure what I need to do before I jump into it. I already have the K5 apart. Doors are off, entire front clip, engine trans, ect. The suburban is big but rides nice. I have been driving it around lately, waiting for it to warm up a bit before I tear it apart.

 

You may have to cut down the suburban rear shaft or just swap the slip yoke if the u-joints are the same size. Also - maybe take the cross member from the sub but then again I think thay are the same. Thats pretty much it. If your blazer tranny is toast then be sure to blow thefluid out your tranny cooler lines so as not to contaminate the TH400.

 

THIS SITE should help with figuring out what is different between these two transmissions concerning the length. To me, I would rather have a 4spd auto than a 3spd and the TH400 sure can soak up HP, but it can also handle a lot of HP and TQ. The TH400 is 1" longer than the TH700-R4 and the transmission mount is much further forward for the TH700-R4.

TH400 Specs/Info

TH700-R4 Specs/Info

I hope to be picking up a 1990 C1500 Suburban (2wd) for salvage parts (5.7L TBI motor, 700R4 trans, steering column, steering gear box, front doors, dash/cluster, hood, etc) and will junk whatever I have left over. I will be paying $200 and for the a running, driving truck that is rusted to pieces, but still has good parts it is a steal! I will be using the 700R4 for my Chevelle and the rest of the parts for my 74 K5.

 

Ok guys this Suburban is really confusing me. Everything I looked at, and researched told me that 1990 Suburbans 1500 came with either a 700 or a 400.

Well it only has 3 speeds, so I figured 400. Right?

Today I was marking all the vaccuum lines and stuff and was wondering, what is this line going to. So I threw the truck on the hoist and raised it up to see a TH350 pan??????????

Everything looks orignal, no drilling in the trans x-member or nething. But still I search around and only come up with a TH350 in this truck. I checked the year in the VIN and door tag, and its a 1990, motor is a 5.7 transfer case is a 241, and by the pan its deff. a TH350 square with one flat corner.

So does anyone else know something I dont? Even at our shop we look up labor rate for transmission r&r and only get a a 700 or 400.

Whats Going On Here? Any insight? DOnt get me wrong, Ide rather have the extra power than have the TH400 sucking it up, but still would like to know why it appears this TH350 came factory...

 

Could be something someone else swapped in before you purchased it. Oh the joys of purchasing a used vehicle. Especially one where there are a wide variety of options as far as power train. With the different cross members used throughout the years (73-91), it could be likely that the bolting looks factory because where it bolts on is factory and there was just a different cross member used.

That does stink though. I really wish the 90 Sub that I am about to purchase was 4wd so that I could take the transmission and transfer case for my 74 K5.