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Is my Truck screwed?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Blue85, Jan 11, 2002.

  1. Blue85

    Blue85 Troll Premium Member

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    What could be causing this problem? Today when taking off quickly, I started to spin a tire and then a second or two later, I heard a grinding noise. Now whenever I give it much gas, it makes this grinding noise and feels like something is slipping/catching somewhere in the drivetrain. It "sounds" like it's coming from the rear end, like maybe I fragged the Gov-lock, but then why would it only make the sound when there is more torque? Or did I crack the carrier for the planetary gears in the 700R-4? Ideas? Experience?

    <font color=green>Today's Forecast: Partly cloudy with a chance of mud</font color=green>
     
  2. Panther

    Panther 1/2 ton status

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    Did you keep moving or just keep spinning one tire?

    You coulda busted an axle shaft or the spider gears on one side.

    Definitely don't drive it until you get the rear diff cover off to have a look.

    <font color=blue>Brilliance is like 4wd, it allows you to get stuck in a more remote location [​IMG]</font color=blue>
     
  3. 6.2Blazer

    6.2Blazer 1/2 ton status

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    My first suspect would be the Gov-Lock. The operation of the Gov-Lock is that when one tire starts to spin it attempts to lock up, it sounds as if something in the locking mechanism is "fragged". Definitely check it out soon as driving around with metal pieces floating around in the housing can take out everything.
     
  4. Blue85

    Blue85 Troll Premium Member

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    It still drives without any problems, as long as I'm easy on the gas. If an axle shaft was broken, I would have to zing the differential up until the gov-lock engaged and it doesn't do that.

    I forgot to mention: I have a 14BSF with disc brakes in the back and the tranny is a 700R-4 that I rebuilt about a year and a half ago. It is still shifting normally.

    Maybe something got it's splines stripped. I guess if I lost a C-clip, that would explain it. The axle would walk out until the brake caliper limited out and then maybe the splines wouldn't quite be engaged and would make the grinding noise. The dragging feel then could be the brake. I'll take a look inside the diff tonight and then maybe drive it without the rear driveshaft to isolate things. Maybe I'm lucky and it's just a fragged U-joint.

    <font color=green>Today's Forecast: Partly cloudy with a chance of mud</font color=green>
     
  5. Panther

    Panther 1/2 ton status

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    Since you're still driving around on it, I would say the Gov Lock too then. When the parts seperate under inertia (at a higher RPM), then it gives you that grinding sound.

    <font color=blue>Brilliance is like 4wd, it allows you to get stuck in a more remote location [​IMG]</font color=blue>
     
  6. Blue85

    Blue85 Troll Premium Member

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    I got it home OK even though instead of having my wife pick me up, I had to pick her up because she locked her keys in the car. Figures. I have popped the diff cover and everything inside looks fine. I can even rotate the gov-lock by hand and get it to preload the clutches and lock the axles together. If I come back to it, I'll pull the cross shaft and spider gears out to have a better look. There are no significant metal particles on the magnet. The driveshaft seems to rotate properly, but I'll pull it and check both U-joints and the splines on the slip-yoke. Then I'll look at the wheel bearings and rear brakes (I haven't done that since I built them). If all of that it is OK, I must be looking at a T-case or tranny problem. I'm still thinking of driving it in front wheel drive, just to check. If it's the tranny, then I am officially VERY unhappy. The forward clutch pack shouldn't be worn out, since there is maybe 20,000 miles on it, so it would seem like a planetary gear problem. Swapping in a TH350 is no longer a good option since I went to 4:10's. Perhaps the solution is to become Omish. Anything else I should check?

    <font color=green>Today's Forecast: Partly cloudy with a chance of mud</font color=green>
     
  7. jackedjimmy350

    jackedjimmy350 1/2 ton status

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    the whole trucks screwed...ill give ya $100 for it!...

    JUST MESSIN

    JUSTIN

    [​IMG]Mash Out![​IMG]
    82 Blazer 1 Ton "Big Nasty"
    78 Jimmy 3/4 Ton
    <font color=red>"Red Dawg" </font color=red>
     
  8. Blue85

    Blue85 Troll Premium Member

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    It seems that I developed two independant problems, but I still don't have it running right. I found the grinding, it was the metal backing of a brake pad hitting the "hat" of the rotor. It seems that the brake backing plate got bent a little bit somehow. Also, some rustproofing material had enough thickness to prevent the rotor from sitting flush on the axleflange. But all of that it OK now.

    After fixing that, I drove it around the block and it seemed fine, except that it was shifting at weird times. Then it stopped shifting out of 1st. I could hear the oil pump when it would do this, so I figured that it was a stuck throttle valve. I pulled the valve body and found that the throttle valve was indeed sticky, as was the accumulator valve. I also reinstalled the spring in my converter lockup control valve (which I was poorly advised to remove by the guys at B&amp;M who probably just want to sell me their band-aid lockup controller) which I've been wanting to do for several months.

    With this done, the truck drove great...for about 15 minutes. Then it decided that it never wanted to shift into 2nd below 3000 rpm. Why? I dunno. It almost seems that something in the tranny is throwing off junk and it is clogging up my valve body. If that's so, then I'm looking at the need for another rebuild. I did find one small piece of metal in the pan. I can't identify it, but it looks like the tip of a thin steel leaf spring or something.

    We'll see if it gets me to work today or not....

    <font color=green>Today's Forecast: Partly cloudy with a chance of mud</font color=green>
     
  9. Blue85

    Blue85 Troll Premium Member

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    Well, it is running consistently now. Either the TV is stuck fairly high (but not all the way) or there is something wrong with the governor. The 1-2 shift is at about 4100 rpm. Tthe sound makes everyone think I'm trying to race them. 3rd gear comes in about 40 miles per hour. I don't know about overdrive. Looks like I'll have to take the valve body out again.

    <font color=green>Today's Forecast: Partly cloudy with a chance of mud</font color=green>
     
  10. muddin4fun

    muddin4fun 3/4 ton status

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    did you check the fluid level? I know it sounds stupid, but many problems I've had with trannies have been low fluid.

    <font color=blue>Answers: $1, Short: $5, Correct: $25, dumb looks are still free.</font color=blue>

    <a target="_blank" href=http://www.bluefox.tv/~lara>My Wonderful Site</a>
     
  11. Blue85

    Blue85 Troll Premium Member

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    Fluid level is right where I've always run it. I did switch to synthetic blend, but there probably isn't even enough synthetic in there to make much of a difference. It has been running OK (still like I described above). My guess is TV stuck again or my gaskets on the seperator plate are starting to wear out. I've had that valve body out at least 4 times now. I'll try to clean it out again tonight and see what that does, but first I'll just check to make sure that the TV cable is all good.

    I'm dreaming of a 4L80E, preferrably one with the Vortec 6000 still attached. Anybody giving one away? I'll split the shipping cost with you. [​IMG]

    <font color=green>Today's Forecast: Partly cloudy with a chance of mud</font color=green>
     
  12. Blue85

    Blue85 Troll Premium Member

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    Well, last night I took the valve body out <font color=red>AGAIN</font color=red> and the throttle valve was stuck <font color=red>AGAIN</font color=red> and there was a good amount of "sand" in the pan for just having done a fluid/filter change a couple of days ago. So I removed and cleaned the TV valve train <font color=red>AGAIN</font color=red> and then no matter how many times I moved it by hand it wouldn't stick at all. I cleaned the pan and put it all back together. It ran good afterwards until the first time I got on the gas, at which point the valve stuck again and I was back to 4000 rpm 1-2 shifts (my neighbors don't like these at 10pm). My torque converter has been shuddering once in a while lately, so I fear that the sand is coming from the lockup clutch. I will now change the fluid a few times in a row or rig up my own fluid exchange at home to get it really clean, put in another new filter and then see if I can't keep that valve from sticking again. I wish that I could put a little filter on the input to it or something.

    Maybe I should just spring for a new valve body (86 IROC, perhaps?) Anyone have an extra Raptor sitting around?

    <font color=green>Today's Forecast: Partly cloudy with a chance of mud</font color=green>
     

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