I need to find what an 84 K5 blazer has.

I have an 84 Chevy Blazer, and I would like to know what is under this pig.  What the axles are, transmission, transfercase, all that stuff.  If you could point me in the right direction to find out myself that would be cool to. Also, I read something about 54"-56" leaf springs. What's the difference and why is one better then the other? Which one does my Blazer have?

The Blazer is a K5, auto, with no engine.

If you want to e-mail please do so at: vthcbbr@yahoo.com

Thank you so much,

Trevor

Go to www.4wheeloffroad.com  and post your thread in the forum to Redbeast.

He knows K-5 Blazers pretty well.

Make sure you tell him 4x4Ranger sent you!

it came with either a th350 or th400 trans, if it was a gas engine it probably had a 305 or 350.. axles are probably 10bolts with probably 3.08s.. for more info you can also check out www.67-72chevytrucks.com they have a very active 73-87 truck forum as well as a blazer burb forum.. and a 4x4 forum)..

as far as 52" or 56" i am not sure what yours has, look at the rear shackle hanger and you should see 2 different mounting points on the frame.. atleast it is this way on the trucks.. if it is farther forward you have 52" and farther back is 56". The 56" flex a bit better but if you are wanting a truc crawler alot of guys even go with 62"s (i believe) in back and 56" up front..

Never came with THM400 and that year did not come with a THM350 either. It has a 700R4 tranny and a NP208 Tcase with 10 bolt axle front a rear. It could have anything from a 3.08 to 3.73 axle ratio. If it has a GT4 on glove box code list it has 3.73's. GU6 is a 3.42 and GU4 is a 3.08.
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  The SnoMan
www.thesnoman.com

Thanks alot to everyone who helped and gave me info. Now, the 700R4 is this a good tranny?  I will be doing mild to extreme driving. I live in VT not to much as far as rock crawling. More of a trail truck.  I want to put in the old tried and true 350, will the 700R4 handle such duties? I will be going with 35" tires. The 10bolts are enogh for me I think, I'll re-gear it with 4.56 gears, will this be adequte enough? I'm not looking for gas savor, just enough to get to the trails.  This is great! I've been looking for help for months now. Thank you all so very much!

Trevor

With at least 4.56's gears (with 4.88's even better) and a aux tranny cooler, the 700R4 will hold up just fine for you. It is basically a THM 350 with different gear sets and a OD added to it and the newer 4L60e is just a electronic version of the 700R4 and uses the same internal parts otherwise. ( it was finally changed internally in 2004 when 4L65e came out with beefed up clutches and sprags) A swap to a THM350 would be a down grade because no OD and a 2.52 first gear vs the 3.06 first gear in a 700R4. and a 1.52 second gear vs a 1.60 in a 700R4. THe only weaknesses in a 700R4 is that the early ones prior to 84 had some issues but they can be easily upgraded to the latest standards. Where 700 R4 got a bad wrap is that 4 wheelers would run stock gears with big tires and no aux cooler and cook the tranny. With some work a 700R4 can handle up to about 600 HP or so. Also shift kits are not a wise addition to a stock 700R4 because they tend to tear out the 2nd gear sprag clutch and toast tranny if you bang the gears hard a lot. Without shift kits, you will have no trouble with the sprags though.

Holy cool, I'm in the middle of doing so much research on this truck and I want to get it right.  I had a scout once and I totally screwed the pooch on that one.  I was 18 what can I say.  Now I got this Blazer and I'm going to try and make it something better then stock.  The body is gone, it was rustzilla.  I'm going to put a truck cab and make a custom bed, BIG suprize, everyone does it. I like it for simplicity reasons.  I thank you again and I will be here everyday with more questions, can you tell I'm green? LOL.  So, 4.88's would be better? I really didn't think of that set. I will be sending the tranny to a place here in VT to give it an update and I will look into the info you've given me and most likley add those items you've mentioned.  Thank you so much. The 10 bolts will be good with 4.88's and 35's?

Thanks again,

So A shift kit is a bad Idea. Thanks, I was considering getting one, but I shouldn't have to. There's a money saver.

Also, real quick, the NP208 I heard isn't that great of a transfer case, Should I look for an NP205? I also heard I should get an NP205 from a Ford because they have a 35 spline shaft. Is that right? Will it fit? The Chevys came with a 30 spline I believe.  What's wrong with the 208?

I will post pictures of my blazer when I first got it, I will update as I go as well.

Thanks again Snoman

I'd be careful with the 700R4 trans. as these don't hold up too well. At least get yourself aux. trans. cooler to handle the extreme temps. and change your trans. fluid on a regular basis or have the old fluid flushed and new trans. fluid put back in. The 35" tires will be really hard on the trans.

10-bolts are pretty weak axels when using anything above 33's., unless your a light foot on the gas pedal. If you wheel your truck hard you will be breaking something in no time!

This is just my opinion as I've seen other trucks break easily with these axels with a big tire size and have seen many 700R4 trans. go up in smoke with a stock tire. Be very careful!

If you properly regear the vehicle, the 208 should give you no problems. Where they suffer the most is when users run big rubber with stock gearing and force the Tcase to work a LOT harder to make up the difference. With reduced torque loads because of proper gearing the 208 will hold up okay for you just keep it serviced properly. Also the 208 has a lot deeper low range for a better crawl ratio than a stock 205 and weighs about 100 lbs less too. Eveen with 4.88's, you will have a decent cruise RPM with the OD in the 700R4. (about 2100 RPM at 65 and even 5.13's would only yeild a little over 2200 RPM at same speed)) As far as axles, in 89, GM beefed up the axles in the rear 10 bolt assembly. They are bigger and stronger. You can use them in your 84 if you change the sprider gears or diff assembly because the spline count is different too. Also gear strength wise, there is no problem with a 4.88 other than the axle beefup I mentioned above. If you realy want to beef up rear axle, find a 9.5 inch 14 bolt semifloater used in some Z71's and LD 3/4 ton trucks that has 6 lugs on it. It is about 35% stronger than a 89 and later 10 bolt and will be pretty much bullet proof with 35's, even with a locker. (stronger axle, pig and housing)  4.88 is the deepest gear made for it.

http://www.coloradok5.com/specs.shtml#1984  

i was thinking of the 84 CUCV m1009 blazer which does have the th400... sorry my mistake.  

Nice link but not accurate because GM never offered the NP241 in the old body style Blazer as link suggests because the front output shaft is on the wrong side for live front solid axle. 88 and newer P/U had the 241 (new body style with IFS) but old body style brazers and Burbs did not. ALso I have never seen a THM400 in one after 80 unless someone put it in and the THM 350 was only used with 6 cylnder base model starting in 81.

The only ones that got a th400 tranny were military models.  As long as you are not dragging the aluminium case in the dirt the 208 is not that bad and if travel is a problem get a slip yoke illiminator kit.  They are plenty strong just not able to take big hits when high centering.  The 205's just got more tricks you can do to them.  Don't get a ford 205 the front out put is on the wrong side.  If the splines are worn just get another shaft to put in the case and overhaul the t-case at the same time.  In that model blazer the tranny 700r4 needs a good rebuild with the right up grades or it will be the weak link.  If you want to know about chevies then the place to go is coloradok5.com.  Alot of people over there or do a search there and you will see alot of people will tell you lower gears for the bigger tires.  If going bigger than 35's might as well look for a 3/4 or 1 ton set of axles that already has the lower gears in them.  

84 and later 700R4 are not weak links, it is the 81 to 83 modles that need a upgrade. GM fixed the 700R4 in 84 and tweaked it a bit in 87 and did not change it again until it was remaned the 4L60 in early 90's and even then the changes were minor and related to electronic controls. It is s sound design. On the axles, at the very most I would upgrade to a 9.5 inch 14 bolt semi floater as it will handle up to 38' to 40 with out much fuss without the added weight andlug pattern hassle of the 10.5 inch 14 bolt. the 9.5 is about the equal of a Dana 60.