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Do I hate my tranny or my rear end more?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by SprinklerGuy, Dec 26, 2002.

  1. SprinklerGuy

    SprinklerGuy Registered Member

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    Alright, I have searched the archives and found many opinions but no clear cut answer.

    1987 suburban with what I assume to be the sm465...granny plus 2,3,and 4 right? I also have 3.42 gears, that I know because of the original options list that the original owner gave me.

    I hate driving this thing! [although yesterday pulling the sportsmans and kids new quad, icey downhills were no problem in granny!] I don't offroad much, bought this cuz I always wanted a burb and it is a pure one with low miles and the original owner was anal! In town, what a pain, the hydraulic clutch sounds easier than the manual one but still a pain in the butt when you are used to autos. And the gearing, 4th gear on freeway at 70mph sounds like it will blow up....3rd gear at 45 is loud too but 4th will bog going up the pass to our home in woodland park. And towing our camper or the quads is a real pain too, always seems to be bogging.

    Question is, if I get an auto put in like another guy on here did, will it still suck because of the 3.42 gearing in back? What about changing the gearing? Or do I find someone to buy this and start over looking for an auto?

    Help! I hate to sound like a newbie, but I really am. This is my first suburban and I love it, but hate driving it. I didn't think I would when I bought it but I do.

    I want to lift it and put larger tires (33") on it but if it is a dog now, what about then?

    Thanks guys, by the way, I really enjoyed the archives!
     
  2. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Trust me.....you hate your axles more. Get lower gears and you'll love your 465.
     
  3. Sandman

    Sandman 3/4 ton status Author

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    He's right. The lower gears will change the whole feel of the truck. /forums/images/graemlins/thumb.gif
     
  4. heavy4x4

    heavy4x4 1/2 ton status

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    </font><blockquote><font class="small">In reply to:</font><hr />
    I hate to sound like a newbie, but I really am.

    [/ QUOTE ]
    /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif I love honesty!!! /forums/images/graemlins/thumb.gif

    But anyway...good question. I don't see alot of people complaining about the sm465 (in fact I'd kill for one in my truck), so your question is rather unique. Here's my suggestion: If you're planning on stepping up in tire size to 33"...do that first, before you touch the rearend or tranny. By stepping up in tire size, 45 mph and third gear will bring your rpm's down, and hopefully to a level which you're happy with. Likewise with the 4th gear and 70 mph. So, like I said, step up to the larger tire size and go from there. Because, if you were to change gearing now to what you like...you'd just have to change it again later when you get the bigger meats.
    Sidenote: (I find it funny that most people with an auto would love to have a manual, and vice-versa /forums/images/graemlins/tongue.gif /forums/images/graemlins/wink.gif)
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Your getting more power to your axles with the manual than an auto, so you hate your axles. (can you tell which tranny I like? : )

    There should be a sticky on this board such as "why the SM465 is the absolute best tranny these trucks came with" lol /forums/images/graemlins/smile.gif

    Have a feeling you'll like the manual better with 3.73's. The gear spacing is still pretty bad (it's no car manual transmission) but with the weight of the Suburban, and climbing mountain passes, numerically higher gears will be a big benefit. Easier starting in traffic, better acceleration, and more "pulling power" should all make it a little more pleasant.

    Then again, my K5 with 350/465/3.42/33's does great in all driving situations IMO, any chance you've got a 305 in that thing? (too late to check profile after you start writing) /forums/images/graemlins/smile.gif

    Of course, with numerically higher gears, you'll be spinning the engine even faster, short of going with an OD setup of some type, the answer is to slow down if you don't like how fast you are turning the engine. These trucks were made when the max speed limit was 55, 70 is way outside of the intended cruise MPH of these trucks, although stock, most will do that ok.
     
  6. SprinklerGuy

    SprinklerGuy Registered Member

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    I know this needs to be searched first, buy hey, we're here now right?

    No it is a 350 stock....nothing ever done to it.

    If I switch gears, I have to do front and back correct? How hard? Should I have it done by a shop? And so on.....and so on..... thanks
     
  7. heavy4x4

    heavy4x4 1/2 ton status

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    Yes, front and rear gears need to match exactly. How hard? Well, that depends on the amount of automotive knowledge you have. Personally, I've done all of the modifications to my 'burb myself so far...but I won't touch a rearend yet. I saw in a magazine the amount of special tools you need to replace gears, and it was a lengthy list of stuff I don't have. So, I say have a shop swap them for you. Now...in some axles it's easier than others to do it correctly...but the axles under you truck are more difficult to get a good gear pattern the first couple of times.
     
  8. 84_Chevy_K10

    84_Chevy_K10 Banned

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    The easiest way to get lower gears is to do what I did--get a pair of 3/4 ton axles. They'll most likely already have 4.10s.

    I swapped to the SM 465 AFTER getting the lower gears. Honestly I really love the combo I have now.

    Can you tell I love my SM 465 too?
     
  9. heavy4x4

    heavy4x4 1/2 ton status

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    I'm going to have to agree with swapping the axles out for 3/4 ton units with the correct gearing. In fact...that's what I'm doing this summer - going from 3.42's to 4.10's by swapping in 3/4 ton front and rear axle assemblies. I figured out my costs, and with everything totalled up...this swap will be about $500 out-of-pocket for me. You, NO DOUBT, will be over that $ figure by having a shop change your gearing.
     
  10. YtseJam

    YtseJam 1/2 ton status

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    Well, I guess I'm in the minority here. I hated my granny tranny! The gear ratios are too far spaced. Your either reving or bogging. I had 3.07:1's than I swapped them out for 3.73:1's. I still hated it. So I plopped in a TH400. Best thing I ever did. /forums/images/graemlins/thumb.gif
     
  11. SprinklerGuy

    SprinklerGuy Registered Member

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    Now that will change things dramatically will it not? If I were to find the 3/4 ton axles and replace my 1/2 ton axles, would I then have a 3/4 ton burb&gt;? Kinda huh?

    Since I haven't lifted it or put tires/rims on it, this won't hurt too much because that is budgeted anyway. From what I understand, the bolt patterns will be different on the heavier axles right? Will my motor suffer from the extra weight of these axles or no problems there?

    What else has to be done or do the axles just "bolt up"?
     
  12. TopOff

    TopOff 1/2 ton status

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    I had the OEM th350/203 in my Blazer. I actually miss the auto now... even for offroad, I miss the auto tranny.

    However, hearing all the offroad stories, I am very happy to have the reliable sm465 - instead of the overheated and overburdened TH350. Although in the five years I had the auto, I never had a problem with it.

    My Blazer is a semi-daily driver, the auto sure was nice around town and in traffic. Going to the manual tranny meant changing driving style, and ignition settings.

    I have 3.73s with 35" tires, and wonder how much more affective some 4.10s will be... I think the higher ratio-ed gear sets 3.73s are better for todays kind of driving - where 75 + MPH is the norm on the freeway. /forums/images/graemlins/eek.gif

    The 3.73s felt just right with the auto tranny. Looking at gear conversion charts and my ACTUAL tire sizes - I should have 3.57s to remain with stock gearing/tire ratios.

    Good luck with your choice.
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    Don't see reference to vehicle weight, so guessing its a 1/2 ton.

    Depends on what gears you want. IMO if you are going to go with large tires in the future, putting something like 3.73's in there now would be pointless. When you go with even larger tires, you'll need even higher (numerically) gears. Best to do it all in one fell swoop, or at least go with something you can use later on.

    Don't know how big I could go with the SM465 and 3.42's tire-wise before I started hating life, but I'm guessing even up to 35" tires wouldn't be too horrid.

    In reality though, its *all* a compromise. To get up a mountain pass with a heavy load, the engine is going to have to spin. 3rd gear isn't high enough to pull 70 at a sane RPM, 4th bogs down too much. Bigger tires make the rear gears less "effective" while numerically higher gears makes the truck easier to get moving, and pull heavy loads, BUT that increases the engine RPM.

    You don't have many choices (especially reasonably priced) in the auto OR manual tranny market to fix too high or too low of a final drive ratio...a 700R4 in your setup would have an OD that is worthless on a hill or towing, (but make cruising a little more tolerable due to the overdrive) yet downshifting on a hill would be the exact same as running the 465 in 4th gear. If you went with a TH350/400, you'd still have the same final tranny ratio as the 465: 1 to 1.

    All I can tell you is my experience. A 350, coupled with a 465, 3.42 gears, 33" tires, in a 5000lb K5, seems to do perfect. Unloaded I can EASILY pull a mountain pass at 70, and cruise easily on flat ground at 60, without the engine screaming. 70 isn't too bad, but I think its more windnoise at that speed than engine. Of course, add a bit of weight to the tail end, and I'd probably not be saying I can pull passes at 70.

    I think what I'm getting at is that you are going to have to compromise one way or the other. Higher freeway RPM's so you can tow, or less RPM's so you can go faster while keeping engine speed down. Both are approached in the same general way, gears, and you'll have to decide which way is best for yourself. The fact of the matter is, the 465 is as close to bulletproof as you are ever going to get, and that right there will save you many $1500 automatic tranny rebuilds. 1/10th of that will buy you a new clutch every 5-10 years. If your 465 holds true to form, you've probably got at least 15 more years before it needs some new bearings.

    FWIW, if we are talking 10 bolt axles, and you only want to go up to something like 3.73's, you can likely buy a used, matched set (front/rear), for less than you can have someone put new gears in your axles for.(anywhere from $3-500 is typical, depending on the work done)
     
  14. heavy4x4

    heavy4x4 1/2 ton status

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    </font><blockquote><font class="small">In reply to:</font><hr />
    If I were to find the 3/4 ton axles and replace my 1/2 ton axles, would I then have a 3/4 ton burb&gt;? Kinda huh?

    [/ QUOTE ]
    "Kinda" is right...you'll still have 1/2 ton springs - leaving you still with 1/2 ton load carrying capabilities.

    </font><blockquote><font class="small">In reply to:</font><hr />
    From what I understand, the bolt patterns will be different on the heavier axles right?

    [/ QUOTE ]
    Yes, the bolt pattern will be different....8lug on 6.5" pattern.

    </font><blockquote><font class="small">In reply to:</font><hr />
    Will my motor suffer from the extra weight of these axles or no problems there?


    [/ QUOTE ]
    No, it will actually thank you because now, with the lower gearing, it will be easier on the engine to get you going.

    </font><blockquote><font class="small">In reply to:</font><hr />
    What else has to be done or do the axles just "bolt up"?

    [/ QUOTE ]
    If you get axles from a 3/4 ton truck...from '77 to '87, they'll bolt right up. Nothing needs to be done - other than a conversion u-joint for the rear and new spring plates/u-bolts...and minor caliper grinding on the front if you want to run 15" rims instead of 16" or 16.5"
     
  15. Z3PR

    Z3PR Banned

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    If you are planing on a lift and larger tires anyways, do it with the axle swap all at the same time so you don't have to keep taking it apart and putting it back together. 3/4 Ton axles are strait bolt in's, and you can usely get them with the lower gears you want. I'd keep the sm465. I'd love to have one in my K5. I like the 14 Bolt FF better then the 14 Bolt SF. That's just my opinion though.
     
  16. SprinklerGuy

    SprinklerGuy Registered Member

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    I guess from what I am hearing.....I should leave it as is. maybe go up to the 33" tires, like I wanted to anyway and see how I like it....worse case scenario, I hate it and I go back to smaller tires.

    As for freeway speeds, I guess I don't hate the engine noise as much as I hate having to shift into 3rd gear to climb with a trailer hooked up. But....maybe I should just slow down and enjoy the view over the guardrails huh?

    Dorian, you are saying I will enjoy the ride more with the 33 inch tires and my same 3.42 rear end? I guess there is only one way to find out...take that rebate check down and put some 33x10.5's on the stock rally wheels and get after it right? Still hoping no lift necessary....factory installed quad socks and air shocks in back.....hmmmmm..I started that thread awhile back huh?
     
  17. dyeager535

    dyeager535 1 ton status Premium Member

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    I don't think I'd go so far as to say YOU will like it better. *I* do.

    As to the slowing down, yeah, because if the hill is steep and long enough, and you have enough weight, no matter what you have for gears, you are going to end up crawling. (look at semi's) But third gear with 33's would let you go a BIT faster than with 31's, 50MPH wouldn't have the engine screaming too much. Now, if you've got stock 235/75R15 tires, then the 33's will be a noticeable difference in RPM.

    The difference with bigger tires will be many. In each gear, you'll be able to go faster with less engine RPM's. The downside here is that getting started is a little tougher. So when starting with a trailer or something, you might notice it a bit more. May actually have to use 1st to get it moving /forums/images/graemlins/smile.gif

    So what you will see in city driving, is less shifting, or at least longer intervals between shifts.

    Going from (assumed) 31" tires to 33's makes the 3.42's feel like 3.21's. Not a huge difference, but a fair amount. What that translates to is *about* 200RPM less at 70MPH in 4th gear. (235/75R15's to 33's is more like 3.00!)

    I like the 33's on my truck with no lift, but as was said in the 33" tire thread, there are a lot of variables that determine fit. I'm sure you can find a shop that will let you try them out. Any shops that won't test fit them, let you return them if they rub, OR one that says adamantly that 33x10.5R15's on stock wheels WON'T (or even will) fit, are ones you should probably avoid.

    Rear clearnace with those tires, I for one, am SURE will not be a problem. I had 2" of sag in the rear, and they were nowhere near hitting in the rear. Maybe if you were missing half of the leaf spring leaves, or had 3000lbs of tongue weight, but not with a "stock" setup.
     
  18. m j

    m j 1/2 ton status

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    the gear spacing is brutal.
    the only way around it is something like a Ranger OD unit from Advance Adapters
    it would give you an OD in 4th to reduce freeway rpm and in 3rd over you would have the spot between 3rd and 4th filled.
    PITA compared to a real close ratio gearbox but for the money...
     
  19. HarryH3

    HarryH3 1 ton status Author

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    That huge jump between 3rd and 4th was one thing that I really hated about the 465 that I had in my '77 Blazer. I had 4.10's and 35's on that truck, but there were still times when neither gear was right when I was up in The Rockies. /forums/images/graemlins/frown.gif

    Most of the power problem is the altitude. The folks that don't live around here don't realize that you're going from around 6,500 feet above sea level to 9,500 feet or so on the way from Colorado Springs up to Woodland Park. A stock 350 in a 6,000 lb truck is wheezing going up that pass. /forums/images/graemlins/shocked.gif

    If you decide that you want to stay with the 1/2-ton axles and go with 3.73 gears, I can set you up with the 3.73 axles from my '90 1/2-ton Suburban for $200 each. I'm converting to the 3/4-ton stuff with 4.56's and 35 inch tires on mine. /forums/images/graemlins/cool.gif I'm just down the pass from ya. /forums/images/graemlins/thumb.gif
     
  20. dleroy43

    dleroy43 1/2 ton status GMOTM Winner

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    you have pretty much the same set up I had.465,3.42 sub10 blts. After exploding my govloc I figurd the cost of fixing or replacing it was much cheaper and hopefully longer lasting to replace the rear.(I also picked up a D60 for the front) Ive replaced the 10blts for 1 ton 14bff with 4.56s. with this it has the power i belive a truck should have. if you get a post 84 14ff its a simple bolt in, mine didnt even need the conversion u joint 465s and subs are 1350s /forums/images/graemlins/thumb.gif /forums/images/graemlins/burb.gif
     

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