So I got a flat tire in the middle of nowhere. I changed the tire. My spare is about 1 inch smaller in diameter and is a road tire. My normal tires are BFG KO2 AT. I heard somewhere that you had to turn off trac control and differential so I did that. After about 40 minutes of driving I smell like a burning rubber smell, and just parked it at the side of the road and am currently sleeping in a hotel. I dont know what to do, nearest dealership is 200 miles away.
I think I messed up my transmission. Flat tire, ran 50 miles on different sized tires.
- Thread starter jcmiro
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How close is the nearest tire shop ?
Running with different sized tires is unlikely to harm the transmission, but could theoretically harm the transfer case, which has the center differential that could be damaged by differences in rotation speeds at the front and rear axle.
My recommendation is to get your GX towed to a tire shop, get the damaged tire fixed or get a new proper-sized tire, (as mentioned above), have the shop drain and refill your transfer case and see how the fluid looks (maybe it is burned?) and then see how it drives. If burned fluid or metal pieces comes out of the transfer case when they drain the fluid, you might have a major issue. If it looks fine and drives fine after the change, I'd be comfortable driving it home.
Just about any repair shop should be able to handle a transfer case fluid change. It's also an easy DIY in a hotel parking lot. You don't need to use a dealer for this.
My recommendation is to get your GX towed to a tire shop, get the damaged tire fixed or get a new proper-sized tire, (as mentioned above), have the shop drain and refill your transfer case and see how the fluid looks (maybe it is burned?) and then see how it drives. If burned fluid or metal pieces comes out of the transfer case when they drain the fluid, you might have a major issue. If it looks fine and drives fine after the change, I'd be comfortable driving it home.
Just about any repair shop should be able to handle a transfer case fluid change. It's also an easy DIY in a hotel parking lot. You don't need to use a dealer for this.
This, but you need to use the correct fluid which is not easy to get. Not sure most show will stock the Toyota TC Fluid.
They can refill with 75W90 gear oil (available anywhere), then it can be refilled with the proper oil when at home. Lots of folks run 75W90 in lieu of Toyota TC.
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I have been running 75W90 on my TCase from Mobil one, no issues. Walmart / Autozone carries tons of it.
With the center diff locked you were not allowing any slip between the front and rear. This may have damaged your transfer case - the diff should have been un-locked to allow for the rotational difference in speed at the front and rear axles. If you are lucky, maybe the burning rubber smell was just tire slip due to the differences in wheel speed, as your rear differential should have allowed for speed differences from one wheel to the other.
You should drain and refill your transfer case fluid as indicated above. Hopefully it is fine but it might not be.
You should drain and refill your transfer case fluid as indicated above. Hopefully it is fine but it might not be.
r2m
Richard
Anytime you run different size tires, only do it on dirt/ice/snow etc. for any distance. I've posted on this forum before that when my wife and I had our All-Wheel-Drive Previa (minivan) with larger tires low profile tires, had a flat and used the factory spare. Ran like that for a few days (not a whole lot of difference between tire sizes). Finally our entire drive train blew up. Luckily we were still under warranty so $3800,00 later (on Toyota's tab 
) we were up and running.
Moral of the story, don't ever run different size tires on all-wheel-drive vehicles, e.g. GX's, certain 4R's, Previa's, Subaru's, Audi's, and the list goes on.
Different sized tires only allowed on vehicles stated as "Part Time Four Wheel Drive".
) we were up and running.Moral of the story, don't ever run different size tires on all-wheel-drive vehicles, e.g. GX's, certain 4R's, Previa's, Subaru's, Audi's, and the list goes on.
Different sized tires only allowed on vehicles stated as "Part Time Four Wheel Drive".
I'm assuming your 1" diff in tire size is compared to stock which would be 3.6% difference in circumference and 22 revs per mile. If you travelled 40mins at approx 50mph, that would be about 33 miles or a diff of 726 revolutions between your spare tire and other tires on your rig. Is that enough to damage transmission or transfer case? I don't know, but the suggestions above to drain and fill of the T case sound like a good start.
BTW, my amateur math calculations were based on the the following site; Tire Size Comparison - https://tiresize.com/comparison/
BTW, my amateur math calculations were based on the the following site; Tire Size Comparison - https://tiresize.com/comparison/
A differential does exactly what it says on the can: allows different rotational speeds between two outputs. I agree with Rednexus that enabling the diff-lock was likely the incorrect setting here. While unlocked the center runs a viscous differential with a fluid coupling separating the front and rear drivelines (similar in function to a torque converter). That should be able to compensate for short distances/low speeds, but as the difference increases by speed or tire size you'll be turning that increases energy into heat and cook your fluid right quick. With it locked, there's nothing to absorb that difference except gears. I would advise against ever locking your center diff on dry pavement.
As a former Subaru fanboy, who's owned 6 different AWD systems over the years, each handles the mismatch uniquely. The range of options goes from forgiving but not very capable: to capable but unforgiving. A locked center is very capable off-road, but very unforgiving in this situation. A Nissan AWD wouldn't even notice the difference because the rear end is basically a tag-axle 99% of the time.
Start with the t-case fluid, and any 75w90 is likely better than what you currently have in there. Smell it on its way out and try to recognize if that's the odor you had earlier. Put some fresh fluid in then drive some figure 8s with the diff *unlocked* and see if it binds up or causes tire chirps. If that behaves normally, then find some loose surface like gravel or sand and try again with it locked.
Good luck.
As a former Subaru fanboy, who's owned 6 different AWD systems over the years, each handles the mismatch uniquely. The range of options goes from forgiving but not very capable: to capable but unforgiving. A locked center is very capable off-road, but very unforgiving in this situation. A Nissan AWD wouldn't even notice the difference because the rear end is basically a tag-axle 99% of the time.
Start with the t-case fluid, and any 75w90 is likely better than what you currently have in there. Smell it on its way out and try to recognize if that's the odor you had earlier. Put some fresh fluid in then drive some figure 8s with the diff *unlocked* and see if it binds up or causes tire chirps. If that behaves normally, then find some loose surface like gravel or sand and try again with it locked.
Good luck.
The rubber burning smell are from the tires getting dragged at different speed. The transfer case are pretty strong. The weakest link are actually front CV. I would not worry at this point. If The transfer case still shift and does not make any noise, you are fine.
This…
You didn’t need to do anything with the diff lock button…it should always remain unlocked, unless off-road and needed.
By pushing the button (locking the center differential in the T case), you physically hard-linked the 2 drive shafts.
Between the rotational difference of 1 of the tires, and the rotational differences every time you went into a curve or corner, you did your drive line no favors.
I hope it works out…get all those fluids replaced pronto!
Redline makes a compatible fluid for the transfer case. Too many people think they're going to blow up their TC if they stray from the Holy Toyota fluid. I switched mine 6,000 miles ago and it's totally fine. Viscosity is the same.
Ravenol makes an affordable 75 weight synth fluid I use.
- Thread starter
- #19
Update, did a transfer case fluid replacement. Toyota tech said it was fine, clear with no bits or pieces. I still get a faint very distinct burning smell when I brake and come to close to a completely halt from speed. Not in turns really like I thought, just braking to a stop.
What do I need to fix?
Many Thnx
What do I need to fix?
Many Thnx
