T-case with VC

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With the front driveshaft off and center diff unlocked the vehicle will go but you MUST rev the motor so the VC will lock, then you can drive till you stop.

Chuck. With the front driveshaft off and in drive (parking brake on) have someone look at the front output shaft on t-case and see if its spinning. It should.
When the center diff is locked (low range) the front output shaft wont spin.
Another was to check is turn off motor and put the t-case in N and tranny in N. With the front driveshaft off or front end off the ground. Turn the driveshaft/front output shaft. It should turn with resistance.

I hope your VC is not locked up. But the fork that locks the center diff could be stuck.
 
[quote author=landtoy80 link=board=2;threadid=6488;start=msg55297#msg55297 date=1067187199]
With the front driveshaft off and center diff unlocked the vehicle will go but you MUST rev the motor so the VC will lock, then you can drive till you stop.
[/quote]

When you tested this was it with the one good t-case you've had? ::)

I also would think that if the fork was stuck you'd get a blinking center diff light. Don't know for sure but Toyota did seem to think of everything else.
 
ok guys thanks for all the help... you guys are great. We concluded from all the info I got here that the TC was locked up. The front output shaft was turning. When we jacked the frontend up off the ground the front tires spun about a half turn as if they were in a bind. I got a TC off of a wreck fzj80 with 24k miles on it for $200. So we swapped them out and the problem seems to be fixed. BUT......

Let me start with this I have had the truck about a month and bought it for a Toyota service manager in Atlanta.

After we got it back together I got to looking at the tires because one of you guys mention the sized being off on them. I couldn't believe it the front tires are 275's and the back tires are 265's!!!! So as long as I don't lock the center diff can I drive it????? Can you believe this? I guess this explains the massive amounts of rubber that was chewed off the front tires!! When the C diff was locked it was chewing them up. So will the VC allow the TC to slip and accomidate the tire mismatch?

Oh yeah... I got the old TC would it be worth cracking open and fixing... What could be wrong wth it? $$$??

Chuck

Thanks again.
 
I'm assuming that both are 70 series tires as the 265 would be a 4Runner size. Running with 2 different sizes will strain you drive line, especially the VC. Because of the rotation difference it will see that as wheel slip. This will also effect the ABS system. I'd park it until all the tires were the same size.

Toyota service manager, one of the 95%
 
Chuck,
>> So as long as I don't lock the center diff can I drive it? <<

You need to give us the exact tyre sizes so we can give you an opinion. All 4 tyres and where they are mounted on the truck. Additionally, what percentage of wear on each if there is a big difference among them.

I would not drive the vehicle unless the tyres are closesly matched... very close.

Just curious, what year model was the wrecked FJZ80 with 24k miles?

-B-
 
[quote author=beams link=board=2;threadid=6488;start=msg55393#msg55393 date=1067207781]
I couldn't believe it the front tires are 275's and the back tires are 265's!!!! So as long as I don't lock the center diff can I drive it????? Can you believe this? [/quote]

The tire size mismatch probably caused all of your problems. I wouldn't drive at all with that setup. I expect the difference in tire sizes cooked your viscous coupling. As you surmized, driving with TC locked would cause even more strain on the driveline.

The person who sold you the 80 with mismatched tires should pick up the repair bill.
 
The fzj80 was a 96' I believe.... Do you think the only thing wrong with the my other TC, the broke one, is the VC? What about other damage? How much is a VC?

Also what about driving it 3-4 miles to get the tires fixed... heck I already driven it about 15 miles or so >:( >:( >:(

Do you really think the Toyota dealer in Atlanta would be liable? I have spent about $500 getting it fixed... :D :D

Chuck
 
Chuck,
You still haven't given us the actual tyre sizes. 275 and 265 don't tell us the size. You have to include the other numbers. Are these 16" wheels?

-B-
 
You got a deal on your t-case.
If you drove with miss matched tires, your vc is most likely trashed. $700+ for a new one.
With the front tries spinning at a different speed than the rear the VC would lock up as a certin speed. This is why it work fine at slow speeds and lock at high speeds.
I bet if you got ALL NEW SAME SIZE AND SAME TREAD tires the old t-case might work but the who knows how much damage has been done.
Just save the old t-case for parts as it is not worth the price to rebuild at this time.

As for driving to get new tires. I assume you dont have the center diff lock switch.
Put the t-case in L and make sure the center diff is locked.
Unplug the plug to the actuator on the t-case. Then remove the front driveshaft and put it in H. THis will lock the center diff so you can drive.
 
OK -B-

the tires on the front of the truck before it was fixed were 265/70 R16 the tires on the back were 275/70 R16. They were all Michelin's and they look like a match but I know now to READ THE FINE PRINT!!! even on a tire. The ones on the front were getting trashed... they are cupped very bad. So we swapped the front and rear, now the 275' are up front and the 265's are in the rear. What about the 15 miles or so I drove.... I'm I back in the same place again???

Speaking of tires what do you guys thing about BFG All-Terrians? Do they handle the highway OK? I have a buddy with 4 fairly new Michelin LTX 275/70 R16's what do ya'll think they would be worth?



Chuck
 
Don't drive it without removing the front driveshaft!!!!!
I sent you a PM look in the top right corner of the page.
If the used tries are ALL worn the same it should be OK but it is best to get new tires and rotate them.
 
Chuck,

>> What about the 15 miles or so I drove.... I'm I (sic) back in the same place again??? <<

You are not doing your VC any good by driving it with mismatched tyres. Hopefully it is not damaged but you'll have to check it after you get matching sizes on the truck.

>> ... what do you guys thing (sic) about BFG All-Terrians? <<

They are good all-around tyres but they are not a MT. Research the archives for dozens of threads on "the best" tyre. Don't get this thread clogged up if you want to get your transfer case issues resolved.

>> I have a buddy with 4 fairly new Michelin LTX 275/70 R16's <<
>> what do ya'll think they would be worth? <<

$214.51. What size is your spare?

-B-
 
IIRC you got the truck from a dealer and those are 4Runner tires and LandCruiser tires. I would get 4 new tires, make that 5 new tires. BFG AT/KO 285/75R16s are a common size that will help out with the price and get you started on the mod list :D. Just be sure to get the speedo gear from Slee to correct for the new size.
 
OK... again thanks for all this great help.

Do ya'll, that's southern for you all..., think I could buy a use VC? And where? Wise?

Chuck
 
Get 4 matching tires or a supply of transfer cases. :cheers:
 
[quote author=landtank link=board=2;threadid=6488;start=msg55351#msg55351 date=1067198117]
When you tested this was it with the one good t-case you've had? ::)


[/quote]

When the NEW t-case started to leak :'( and Toyota said they would replace it 8) I did some tests with it.
With the front driveshaft off and in D the front output shaft would spin. When I reved the motor the VC would catch and I would move. I should of done more tests to it but I didn't want to trash it.

I would say the VC is like adding a limited slip to a diff.

For those that don't have a center diff lock switch, get one. But if you need to be locked in H. You can go to L and get the t-case center diff locked and unplug the actuator at t-case or find the fuse that goes to the actuator and pull it. Then go to H and you will be locked up. See, adding the switch would be "more easier?
 
Chuck,

I don't think driving the truck 15 miles to a tire shop for new tires would be a problem if you stay off the freeway. Low speeds generate lower heat, and it can tolerate some f/r axle speed differences - that's the whole reason it exists. However, many owners replace tires 2 at a time and drive with significant f/r axle rotation speeds, which stresses the VC at sustained higher speeds.

As an example, my Subaru states in the owner's manual that a maximum circumferential difference of 1/4 inch is allowed. That's pretty tight allowances, since it equates to a diameter difference of less than a tenth of an inch. Different vehicle, different system, but it serves to make the point that a full time system should only have matching tires. I think you should bite the bullet and replace all four.

It's worth considering how poor your snow/ice traction on the road would be if the tires were not EXACTLY the same diameter. Putting the same torque to tires of different diameter means the smaller one will break loose first on a low traction surface (tire diameter is simply a lever and the shorter lever generates more force at the working end). So if you're out there proud of the traction of your 80, but wondering why you constantly get wheelspin at stoplights and can't beat a mundane Chevy truck across the intersection - there's your answer.
Translate that to rock crawling where you're locked up. Now you've got serious fighting between the tires. Whatever traction's left after one tire's done fighting the other for dominance will be available to climb the rocks. Again, you've dramatically diminished your highly capable vehicle's practical effectiveness - perhaps sacrificing 20% of the available traction.

Same diameter good. Different diameter bad.


Doug
 
FWIW, not only don't I rotate in my spare but I don't rotate my tires at all. After 60k they have worn themselves to were they are "balanced" in size to where their positions. If you are going to drive the truck down to get tires swap one of the fronts with the diagonal rear. That way the front has one small and one large and the rear is the same only opposite. This will help balance the sizes and greatly reduce the risk. And if you don't get the same size tire as the spare get 5 tires and throw out the spare.
 
Alright guys I got a set of 275/70 R16 LTX's and the TC is working properly.... Praise The Lord!!! I really appreciate the help. Just a thought for the VC conscious folkes out there.... I drove over 5000 miles with the mismatched tires before she broke.... all highway ~ 65mph. That little "tuna can" must be pretty strong....oh yeah did anyone ever cut into one to see what's inside??

Thanks again,

Chuck ;)
 
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