Hello there,

My fiance's little brother has a 94 blazer 4x4 with the auto and the Vortec 4.3L with about 143K miles!!!!!! It runs and looks great, but last week the tranny started screwing up. From my understanding it will shift into 1st and 2nd, but no 3rd or 4th. So I am assuming its about time for a new one. You agree? Since he is only 16 and short on money I want to help him out. I'm looking for a used lower mileage tranny. Since it wouldn't be the best idea to dump a bunch of money into a 1st vehicle. I just want it to get him through for a few years. From my past experiences I am guessing it is a 700R4 4x4, right? Which /vehicles/years will work, S10, blazer, jimmy 4x4? Is there anything tricky envolved in changing a tranny on one of these blazers? Any special tools? Just looking for some basic information about changing the transmission in this blazer before I tear into it. I would like to keep the surprises to a minimum, and make it go as smoothly as possible. Thanks in advance for your help guys!!!!!

 

im not sure bout the 4x4 but switchin the trannys is easy your only bad part is the top 2 bolts that hold the tranny to the engine are hard to get out. You need the simple tools wrenches, sockets, and ratchet, but lots of extentions. In 94 i believe its a 4L60E. If you need anything else just ask.

 

It should be a 4l60 or 4l60E, newer versions of the 700R4. Personally I would call the salvage yards and see what they have. They will be able to cross refference it to other vehicles. The 4.3L and 4L60(e) tranny is available in many vehicles. From the s-series pick-ups/Blazers to fullsize 1/2 ton pick-ups, Astro vans, etc. Since his is 4wheel drive make sure you get a 4wdr tranny. The output shafts are different on 2wdr trannies and 4wdr trannies. Also make sure the tranny is from a 4.3L engine or any V8. Do not get one from a 2.8L engine, it won't bolt up.

Around here a used tranny will run about $500 bucks. Stop in your local autoparts store and buy all new gaskets for it (input, output, dipstick tube, tranny pan, etc) new tranny filter, and a chemical to treat for tranny shock. Tranny shock is when a used tranny gets new fluid, doesn't happen in a tranny that had the fluid changed at regular intervals, however you don't know the history of a salvage tranny so add the treatment. IT will protect the internal seals and clutch packs in the tranny. It's a small price to pay when you consider dropping in another tranny becuase you fried this one in 6 months.

Tips and tricks. Get a Chilton or Hanyes manual. They do a pretty good job covering the whole process. Several things I highly recommend. Help, get him to help you. Have about 2' of extensions and a wobble socket to fit the bellhousing bolts (I think it is a 18mm), otherwise you will have to lift the body like the Chilton book recommends (more work). Get the truck as high off the ground as possible. The tranny is about 2' tall on a tranny jack. You will need about 2' between the frame rail and the floor, otherwise you will have to drag it out on the ground (measure first), not to tough if your a big guy. The tranny weighs about 175 pounds, don't hurt yourself. I didn't have the 2' nor a tranny jack. I used a floor jack on my first tranny swap. It's a balancing act, and use blocks of wood to protect the tranny pan. I slide my tranny off the jack and onto a piece of old carpet. Then dragged it out on the carpet, much easier to get out. Getting it in is a real treat. Someone has since suggested using rachet straps for removal in installation, haven't tried that yet. Have some white out to mark your driveshaft parts, they are balanced as a unit, keep it that way or you will end up with drivetrain vibrations. Don't lose any of the needle bearings in the u-joint caps, tape the caps on after you get them out. Get seperate pans (I used pie tins and old peanut butter jars) to hold the various nuts and bolts. Put the nuts and bolts with the parts they came from.

Here is a link to a '87 700R4 tranny rebuild I did last summer. I swapped out a few trannies before I attempted the rebuild.
http://offroadworld.tenmagazines.com...66-album-10614

If you ahve any questions. Post them up in this forum or eamil me. I am marking this thread to keep an eye on it.

One last thing, plan on spending the weekend swapping them around.

Pic of my son helping me

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