Is my VC siezed? (1 Viewer)

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Feb 21, 2020
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97 LX450 - just took off my front drive shaft chasing a vibration (happened to actually be the DS for once), however, when I was down there after disconnecting the axle side of the shaft I was not able to turn the front independently (back drive shaft would move in tandem). Truck was on ground while doing this, and transfer and trans were in neutral. I have a CDL but it was NOT on which is my concern - I was told front DS should spin independently by hand once you disconnect from axle side.

1.) is my VC shot?
2.) how do I test CDL switch to find out?

thanks!
 
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If you pull the front shaft and can drive around normally, without the center diff locked, then your VC is no longer viscous and is now a solid coupler.

If the VC is failed you can easily remove the it and enjoy your 80 without it in place. I've never driven an 80 with a good VC but my 80 drives great in all conditions that I've encountered with no VC. Removing the seized VC in my 80 resolved many issues in high-traction situations.
 

enox

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If you pull the front shaft and can drive around normally, without the center diff locked, then your VC is no longer viscous and is now a solid coupler.

If the VC is failed you can easily remove the it and enjoy your 80 without it in place. I've never driven an 80 with a good VC but my 80 drives great in all conditions that I've encountered with no VC. Removing the seized VC in my 80 resolved many issues in high-traction situations.
I too have removed mine and have no issues.
 
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Ok so I just got under the truck and had my wife press the CDL. The CDL actuator is definitely moving (or trying to move) - from the other posts it seems it wont even try to move and makes no noise if it is the actuator. Light on dash lights up as well.

is it correct that the front DS flange (no ds installed) should move independently of the rear? If that is the case then it would seem to be my VC. Thanks for all the help.
 
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I can't confirm if you should be able to move it by hand, a lot of factors there. The VC should not be stiff enough for you to drive normally though which is why I recommended that test instead. Can you drive it around without the CDL engaged and with the front shaft out?
 
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If you pull the front shaft and can drive around normally, without the center diff locked, then your VC is no longer viscous and is now a solid coupler.

Best way to make the diagnosis I think.

Mine was seized when I bought it. I pulled it out and never put one back in. No issues, doesn't drive any differently.
 
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I can't confirm if you should be able to move it by hand, a lot of factors there. The VC should not be stiff enough for you to drive normally though which is why I recommended that test instead. Can you drive it around without the CDL engaged and with the front shaft out?
I am going to go try right now. No harm in driving without CDL engaged and front ds out?

What should i be listening/feeling for?
 
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If the truck doesn't move well, makes strange noises, lurches, etc. then stop the test and/or engage the cdl to resume driving.

I drove my 80 without a front driveshaft and with a seized VC for a period of time before I could pull the VC out. It drove great, there were no noticeable differences besides all of the tire/drivetrain binding went away :)

If your VC is either good or only partially failed then you may get limited drive to the ground. This will quickly heat up the VC and allow you to ensure that it's destroyed relatively quickly. If the truck doesn't drive like normal when you test then use the CDL to drive it around or put the front shaft back in so that you don't burn up the VC.
 
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Ok, just got back. Drove 100% normal and felt zero difference. I guess my VC is bad :( I also had the exact same binding and screeching of tires prior to taking my DS out so another sign the VC failed.

two question:

1) how many bananas does one need to remove the VC? I will look up the threads obviously on how-to but I am only a 1.5 banana mechanic (gave myself half a banana for doing my own knuckle rebuild but that is the most advanced thing I have done).

2) With a fried VC is it going to damage anything to put the DS back in? Other than tires binding on turns of course.
 

enox

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1) how many bananas does one need to remove the VC? I will look up the threads obviously on how-to but I am only a 1.5 banana mechanic (gave myself half a banana for doing my own knuckle rebuild but that is the most advanced thing I have done).
You can absolutely remove the VC then. It's :banana:
 
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With front shaft out you should def. have no tire/drivetrain binding. If you have that going on without the front DS then you have a diff locked or have other issues.

Removing the VC is much easier than a axle/knuckle service. Just drop transfer case oil, pull front end of rear drive shaft, pull transfer cover, pop off VC snapring and slide out the VC, clean surfaces and add sealant/goop then re-assemble. Only special tool you may need is for removing the snapring I'd guess. Only materials the sealant and new gear oil.

Don't drive on pavement with a fried VC and both shafts in, it will wear/damage driveline components. Just leave front shaft out if you need to use the truck until you can pull the VC.
 
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@jpoole yes there is no more binding with the DS out (was binding before i took it out).

Really appreciate all the help here! I will keep DS out for now and attempt to pull the VC this week. Will keep everyone updated.
 
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You can absolutely remove the VC then. It's :banana:
That is super helpful to know! Thank you!

thought I had good luck for once because pulling my DS made my vibration go away (almost never the case in every thread I have read) and now this haha. I guess I will now be adding VC delete to my resume.
 
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From another thread: To test if the VC is bad, make sure the center diff is not locked, block the rear wheels, jack up one front tire and put the t-case in N. Try and turn the front tire that is in the air. If the VC is working correctly you should be able to turn the front tire with some resistance, if not, then it is seized.
 
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Thanks for all the help here, Gents. Removed the VC yesterday and that fixed all of my issues. Was an easy enough job thanks to the forum members.

No more binding. Also got rid of my vibration and the source of it was the seized VC trashing all of the U-Joints - only have my new front DS in at the moment but zero vibration on highway now (even went 80 mph with out getting too scary). Previously had only the rear DS in and i was getting a vibration in between 65-75 mph on highway.

To confirm a previous question I had here, if your CDL is unlocked (with TC in neutral) and you have removed the diff side of the front DS (or rear DS i guess too) you should be able to turn the side connected to the TC independently. If you aren't changing u-joints or messing with the DS the easier way to tell is as @WCBlueSky describes above.
 
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Thanks for all the help here, Gents. Removed the VC yesterday and that fixed all of my issues. Was an easy enough job thanks to the forum members.

No more binding. Also got rid of my vibration and the source of it was the seized VC trashing all of the U-Joints - only have my new front DS in at the moment but zero vibration on highway now (even went 80 mph with out getting too scary). Previously had only the rear DS in and i was getting a vibration in between 65-75 mph on highway.

To confirm a previous question I had here, if your CDL is unlocked (with TC in neutral) and you have removed the diff side of the front DS (or rear DS i guess too) you should be able to turn the side connected to the TC independently. If you aren't changing u-joints or messing with the DS the easier way to tell is as @WCBlueSky describes above.
Glad to hear you got your 80 fixed up.

Would like to reaffirm--replacing U-joints after removing the VC is a GREAT idea. My 80 went about 1000 miles with a bad VC and the U-joints were causing some vibrations. They didn't have any play in them yet but they didn't feel smooth. Replace the, with OEM Toyota joints otherwise you're going to have to replace them twice like I did...

While relatively expensive for 4 U-joints, the Genuine Toyota joints are well worth the money. Made all the difference in my 80.
 
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Glad to hear you got your 80 fixed up.

Would like to reaffirm--replacing U-joints after removing the VC is a GREAT idea. My 80 went about 1000 miles with a bad VC and the U-joints were causing some vibrations. They didn't have any play in them yet but they didn't feel smooth. Replace the, with OEM Toyota joints otherwise you're going to have to replace them twice like I did...

While relatively expensive for 4 U-joints, the Genuine Toyota joints are well worth the money. Made all the difference in my 80.
I have never heard that before. Thanks for the heads up. Will take these duralasts back then.
 
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Just curious if you rotated tires regularly or ever ran with one or two of slightly different wear?
 
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Just curious if you rotated tires regularly or ever ran with one or two of slightly different wear?
Since i have owned the truck (7 months) i have only had same size tires and rims on all 4. I believe the VC was seized from the day i picked it up and it just took my getting used to the vehicle (and searching this forum) for me to realize the VC was shot (first LC I have owned). The PO never took it offroad and had like 22 inch street wheels on it before so I dont doubt he ran with different size tires at some point.

If there is anything I can confirm on this forum it is that just because an LC has only 170k miles does not mean it is in mechanically great shape. In hindsight would much rather buy something with 225k-250k miles maintained by an enthusiast - but luckily I have her in pretty great shape after 7 months.
 

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