5th Gen - Front Diff and Transfer Case work only in 4Hi/4Lo ?
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samwhich
New member
Correct, and that is why it is also good practice to put it in 4HI every so often and put some miles on it.
This is only partially true. The front differential uses ADD (Automatic Differential Disconnect), which disconnects one CV shaft (passenger side, I think) from the differential. That allows other side CV shaft to drive the internal spider gears. These spin freely, but with no load, while the ring and pinion remain stationary. Since there is no load on the moving parts inside the diff, wear and heating are minimal and the oil should last a long time. The lubrication remains very important, however, because those spider gears are turning very rapidly.
The transfer case provides power from the transmission to both the rear drive shaft and the front drive shaft. Obviously the part that powers the rear drive shaft is fully operational even in 2wd, so requires full lubrication. The section that drives the front drive shaft is stationary in 2wd, but that's actually a small part of the tcase. Again, you need good oil in the tcase at all times, and since parts of it are always under load, follow the normal maintenance schedule as suggested in the manual.
Two reasons for exercising 4wd monthly.
- Keeps the actuator from getting sticky
- Rotates the seals and bearings involved with the front output section of the tcase, the front drive shaft, and the ring/pinion of the front diff. In both the tcase and diff, oil is sloshing around whenever you drive, even in 2wd, so parts are not drying out and rusting during long 2wd periods.
Thank you RonJR for the detailed explanation.
I recently changed the oil on the rear differential of my new 2018 4Runner SR5, and the oil was REALLY dirty and full of metal shavings (car had only 5000 miles at that time, I am at 6000 miles now). I have a post on this forum covering that.
I am trying to figure out if I need to do the same for the TC and Front Diff, to get rid of the brake-in stuff in the oil. I do light off-roading in weekends, nothing major. I think I might have about 250 miles in 4HI/4Lo all in all.
I have the tools and the oil, that's not a problem, will not pay the dealer to do it.
I recently changed the oil on the rear differential of my new 2018 4Runner SR5, and the oil was REALLY dirty and full of metal shavings (car had only 5000 miles at that time, I am at 6000 miles now). I have a post on this forum covering that.
I am trying to figure out if I need to do the same for the TC and Front Diff, to get rid of the brake-in stuff in the oil. I do light off-roading in weekends, nothing major. I think I might have about 250 miles in 4HI/4Lo all in all.
I have the tools and the oil, that's not a problem, will not pay the dealer to do it.
DesertCanyons
New member
Front slip differential and changing the oil
In 4Hi it's very hard to take sharp turns on pavement with the T4R. I'm not sure exactly what the mechanical reason is. There may be more to this than I know.
Before you change the front differential and the transfer case oil take the car out anywhere and drive it in 4Lo for a mile or so. You can do it on dry pavement if you have a place where you can drive straight, without turning much. You can turn a 180 and return if you turn wide and very slowly. I've done it without issues. This stirs up the diff fluid and puts any gunk or metal shavings into suspension in the oil so you can drain out the dirt, etc with the oil. Do this just before you drain the diff and transfer case oil.
I only get to drive my T4R in 4Lo about once a month if I'm lucky here in Los Angeles. After 26,000 miles the front diff oil was very dark and dirty.
I'm not sure but I think the front differential (limited slip?) turns whichever CV axle shaft has less traction/resistance. This is like any 2 wheel rear axle drive car. The wheel with less resistance turns so you can go around corners without skidding the tires on the inside track.
In 4Hi it's very hard to take sharp turns on pavement with the T4R. I'm not sure exactly what the mechanical reason is. There may be more to this than I know.
Before you change the front differential and the transfer case oil take the car out anywhere and drive it in 4Lo for a mile or so. You can do it on dry pavement if you have a place where you can drive straight, without turning much. You can turn a 180 and return if you turn wide and very slowly. I've done it without issues. This stirs up the diff fluid and puts any gunk or metal shavings into suspension in the oil so you can drain out the dirt, etc with the oil. Do this just before you drain the diff and transfer case oil.
I only get to drive my T4R in 4Lo about once a month if I'm lucky here in Los Angeles. After 26,000 miles the front diff oil was very dark and dirty.
I wasn't clear in my first post, but when I was talking about ADD operation, that was referring to what happens when you are in 2wd. That's when the ADD disconnects the passenger side CV axle from the differential. Anytime you are in 4wd, both CV axles are solidly connected to the diff, and operation is as you have described.
The reason that 4wd vehicles don't turn sharply well on hard pavement is that the front wheels have to travel further than the rear wheels in a turn. Since the 5th gen has no center differential in the transfer case, the only way for that difference to be accommodated is for the wheels to slip. That works OK on low-traction surfaces, but not so well on pavement or slick-rock.
AWD or full-time 4WD vehicles have a center differential in the tcase which allows the front wheels to turn faster than the rears.
The reason that 4wd vehicles don't turn sharply well on hard pavement is that the front wheels have to travel further than the rear wheels in a turn. Since the 5th gen has no center differential in the transfer case, the only way for that difference to be accommodated is for the wheels to slip. That works OK on low-traction surfaces, but not so well on pavement or slick-rock.
AWD or full-time 4WD vehicles have a center differential in the tcase which allows the front wheels to turn faster than the rears.
Agent_Outside
New member
A typical 4WD system is RWD until its mechanically locked into 4WD. When it's in 4WD the front and rear are locked together and forced to spin at the same speed, but that's not physically possible unless you’re driving straight or a tire is slipping. When you’re turning the path of the front wheels is longer than that of the rear wheels - an easy visual to picture in your head is a semi making a right hand corner at an intersection. They pull very very wide into the intersection almost crossing into the oncoming side of the road with the cab yet the back wheels of the trailer barely making it around the corner without hopping up on the curb. The front wheels traveled a further distance than the rear wheels did. All vehicles do the same thing just on a more compact scale. With a vehicle locked in 4WD the drivetrain WILL start to bind up while driving anything but straight ahead, the result is that something has to release the tension - either a front tire drags or a rear tire spins to make front axle speed match the rear axle speed, or the inner workings of the transfer case blow out the side of the housing and dump onto the road. The latter being the least likely but it does happen, especially over time with repeated binding. Try pulling into a parking space with a vehicle locked in 4WD, it'll get stuck from binding up so bad while trying to turn. This is why you use 4WD to get unstuck or off
Roaring on surfaces where it can slip easier than dry pavement. Driving around all the time in the snow in 4WD you’re forcing tires to break traction and slip which obviously isn’t doing you any favors.
Very good info.
Another thing I found on these forums is that the Transfer Case requires a special Toyota oil that is a straight 75W, not a multigrade, like a 75W-90. Also, it seems that this Toyota 75W oil has a special additive package ... I will look more into this.
Lots of people report using a 75W-90 multigrade in the TC without issues, but I don't think my OCD will let me do that now...
The hunt for the Toyota 75w TC oil starts ...
Another thing I found on these forums is that the Transfer Case requires a special Toyota oil that is a straight 75W, not a multigrade, like a 75W-90. Also, it seems that this Toyota 75W oil has a special additive package ... I will look more into this.
Lots of people report using a 75W-90 multigrade in the TC without issues, but I don't think my OCD will let me do that now...
The hunt for the Toyota 75w TC oil starts ...
Industrialwrench
New member
Change your fluids by time, if not already by miles.
Oil won’t last forever, regardless of your total 4x4 miles. Gearboxes are vented to atmosphere, which mixes with moisture in the air. This turns your oil to poo.
Oil won’t last forever, regardless of your total 4x4 miles. Gearboxes are vented to atmosphere, which mixes with moisture in the air. This turns your oil to poo.
Agent_Outside
New member
Just look for the GL5 rating on the bottle and your good. Synthetic 75-90 GL5 is very common.
STX4Runner
New member
Royal Purple Synchromax is a substitute for the $55/L Toyota 75W fluid. I just put it in my T-case a few weeks ago. FWIW, I had never changed my front diff or T-case fluid and just passed 98,000 miles recently. Both looked fine when I drained and refilled them recently. Rear diff looked fine too. I had last changed it about 50,000 miles ago.
I don't mind paying for the Toyota TC oil if I find it.
Main thing is, I didn't expect to find the rear diff oil so dirty and with so many metal shavings after only 5000 miles. I took a sample and will have Blackstone do an analysis. After a couple of days in the sample bottle, the metal particles accumulated to the bottom, and the remaining liquid is slightly yellowish, very watery and it doesn't feel slippery at all to the touch.
So now I am planning to check on the TC and front diff fluid as well. Might be a good idea to clear out the initial factory fill. Will probably wait until I hit 10k miles, which will be soon.
I trust less and less the car manufacturers with their planned obsolescence policy ...
Main thing is, I didn't expect to find the rear diff oil so dirty and with so many metal shavings after only 5000 miles. I took a sample and will have Blackstone do an analysis. After a couple of days in the sample bottle, the metal particles accumulated to the bottom, and the remaining liquid is slightly yellowish, very watery and it doesn't feel slippery at all to the touch.
So now I am planning to check on the TC and front diff fluid as well. Might be a good idea to clear out the initial factory fill. Will probably wait until I hit 10k miles, which will be soon.
I trust less and less the car manufacturers with their planned obsolescence policy ...
1000MPH
Senior Member
C'mon, how many Toyota rear dif and TC issues have you heard of that are oil related?
DesertCanyons
New member
Drive Train Oil Change Intervals
That's not what the service manual recommends. According to the owner's manual if you're driving off road a lot or towing trailers you should be changing all 3 drive cases every 15,000 miles. If you're driving mostly on the streets and highways then the interval is closer to 30,000 miles. And when driving in 2Hi on streets and highways the rear diff gets a lot more use and wear than the transfer case and front diff.
See my post above about stirring up the sediment in the transfer case and front diff by driving in 4Lo just before changing the oil. If you don't stir up the drive train oil before you drain it, it will appear clean and clear.
That's not what the service manual recommends. According to the owner's manual if you're driving off road a lot or towing trailers you should be changing all 3 drive cases every 15,000 miles. If you're driving mostly on the streets and highways then the interval is closer to 30,000 miles. And when driving in 2Hi on streets and highways the rear diff gets a lot more use and wear than the transfer case and front diff.
See my post above about stirring up the sediment in the transfer case and front diff by driving in 4Lo just before changing the oil. If you don't stir up the drive train oil before you drain it, it will appear clean and clear.
STX4Runner
New member
I drove in 4HI before changing the front diff and t-case, and just drove around in 2wd for a bit before doing the rear to make sure and stir it up. They all were fine. There was paste on the magnet, but that's what it's supposed to do.
You'd have to be living on the Rubicon or using this for a tour guide service in Moab to need to change the fluid every 15K miles, and even every 30K for just street driving is too often. The vast majority of people (i.e. not on this forum and aware of this stuff) never change their diff fluids and are fine. Changing mine at those intervals I guarantee is fine.
This is my first Toyota, I'm working on my OCD, believe me I don't think about oil changes all the time, but when I do .... :rofl:
Bt the way, today dealer quoted me $100.- / liter for the Toyota super-special 75W transfer case oil ...
They didn't have it in stock but said can order it for me if I wanted it.
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Theomoji
New member
Hey so my 2014 toyota 4runner SR5 Prem will not lock 4Lo, the light blinks and sound of beeping goes off when i do try (in neutral). My 4Hi works fine though. I just let it at my local Toyota dealer for repair. Do you think it's possible it's just the actuator that need changing and not the whole front differential? Since 4Hi is locking just fine?
You have an actuator problem with the transfer case. The front diff is likely just fine. If the transfer case is not cycled into 4LO regularly, the actuator can stick and refuse to shift into 4LO when you ask it to. The fix is to remove the actuator and free it up. Unfortunately, the only "dealer approved" way of doing that is to remove the transfer case and replace it and the actuator to the tune of $3000 plus. There is no Toyota approved field method to remove just the actuator from the tcase and replace it and get it re-timed properly. Frustrating when the only thing really wrong is a sticky shift rail which you could fix with one gentle tap of a plastic hammer if you could just get access to it.
That being said, there are people on the forum who claim to have successfully removed the actuator from the tcase in situ, freed it up, and successfully retimed the actuator gears so that it all works when put back together. Not for the faint of heart.
Sometimes you can free up the actuator by parking in your driveway, engine running, parking brake applied, and transmission in neutral. Just continuously cycle the 4WD knob from 4HI to 4LO and back again. Eventually it may "unstick" and start working. You won't hurt anything by doing that - the computer is smart enough not to force or burn out the actuator if it is stuck. That's what the beeping is about. The computer is telling you things are stuck and it has quit trying. You haven't much to lose by trying, anyway. The alternative is $$$$.
BTW, if you have a 4th gen with a center diff lock, that needs to be regularly cycled as well or the same thing can happen.
Theomoji
New member
Thanks for the quick reply and reassurance. I am aware of how much it cost. I've called all the transmission shops in LIC (in NYC), and only 1 even did this type of work. And he said I couldn't order the part myself, that i have to obtain it from him. He most likely charges around the same price as dealership anyway. Toyota dealership quoted me today 1/3/2022 $1200 (for the actuator/minor discount) + $1875 for the work. This would be done in 2 days. I just hope the cost stops around there and not have to do a front diff on top of that. I didn't even ask how much the front diff part will be but the service guy told me the work for the front diff would be $875.
UPDATE: Toyota said it wasn't the actuator, it's the Safety Neutral Switch. Along with transmission oil change + transfer case oil change (already bought 2 x 75W oil for this), it's totally $1200. I googled this switch to be only a $140-179 part. I guess most of the money is going into labor.
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