[Jan777]

I had to change the chain in the transfer case for the second time in 3 years! Wonder if others from the V8 community have the same problem?

Identical chains are used in transfer cases of various Toyota cars (LC, Prado, Hilux etc.) and my mechanic tells me that he has to change them regularly. His workshop services about 80 T4Rs 3rd generation from a local energy company. Work horses running on diesel engines.

The Toyota rep started talking about replacing the entire transfer case, and a bill that runs in the thousands!!! I got the job done for about 500 euro (550 USD), incl. oil change and new brake pads. Its a used chain, but in perfect condition and with the new chain the actuator to switch btw 4Hi/4LOW and the DIFF/LOCK is working fine again. No need to get a new actuator. The main failure symptom was that the chain jumped sprockets when high power was applied, i.e. off-road, climbing uphill and rapid acceleration.

Pics from my chain. And a pic from a transfer case, not mine, just for into on the location of the chain.

[Jan777]

not mine, just for info

[Flighht2k]

Maybe the mechanic is doing a terrible job at rebuilding it. There is no way the chain needs to be replaced that often. I have 150000 miles on my gx and it’s the original t case. Had a 4th gen before that with 140000 and the original t case.

[Inv4drZm]

I've never heard of it needing changed, and I offroad it a decent amount.

[Jan777]

Well yeah, mine has now 190.000 miles and the replacement was done at 150.000. Judging by the dozen or so chains in his workshop, it is definitely not such a rare problem.

[08TxRunner]

Maybe it's because he keeps using used chains? I can't imagine how a chain jumps teeth if it's installed properly and there is no slack.

[RonJR]

I agree that it's not a common problem across the world. I've been reading these forums daily for 5 years or so and this is the first I've heard of any problem with a tcase chain. Can't say what went wrong with yours, but gearboxes normally fail due to inadequate or contaminated lubricant, or extraneous pieces of metal getting into the works. Once something breaks inside, the pieces can trash a lot of other things.

If the tcase has always been kept full of clean gear oil of the proper viscosity and rating, there should be no significant wear on parts, including the chain, even at 150-200,000 miles.

[rdruss]

I have an '03 V8 AWD so chain working all the time, 133K, no problems.
All driving is on-road.

[duffdog]

Is it just me or is buying a completely new transfer case direct from Toyota less money than paying someone to change the chain incorrectly 3 times? This is one of those "problems" that never seems to happen to anyone except people who are determined to DIY it.

Sort of like having "problems" when making your own homebuilt aircraft.

[Jan777]

I got the responses I was looking for, thanks. So it is NOT a common problem, at least not in this forum, which are, to my understanding, mostly U.S. based readers/contributors.

Just fyi: we drive a bit faster in Europe, my constant travel speed with the T4R on the highway is between 80 to 100 mph. And each leg of the trip is about 450 miles.

Three years ago I had a loss of gear oil in the transfer case due to faulty gaskets and that, together with the high-speed, long distance trip, killed the original chain.

The replacement came from a used truck and served me well for the last three years. You have NO IDEA what Toyota asks for these rather simple chains in Europe!

I have now found a source for high quality new chains for normal prices (around 300 USD). That will hopefully solve the problem for good.

[Flighht2k]

Originally Posted by Jan777

I got the responses I was looking for, thanks. So it is NOT a common problem, at least not in this forum, which are, to my understanding, mostly U.S. based readers/contributors.



Just fyi: we drive a bit faster in Europe, my constant travel speed with the T4R on the highway is between 80 to 100 mph. And each leg of the trip is about 450 miles.



Three years ago I had a loss of gear oil in the transfer case due to faulty gaskets and that, together with the high-speed, long distance trip, killed the original chain.



The replacement came from a used truck and served me well for the last three years. You have NO IDEA what Toyota asks for these rather simple chains in Europe!



I have now found a source for high quality new chains for normal prices (around 300 USD). That will hopefully solve the problem for good.

So loss of fluid from a crappy rebuild and then using a used chain that failed.

[RonJR]

Well, loss of fluid will do it. Thanks for the extra facts - they explain a lot.

Because of your continuous high speeds, you are probably running your tcase and diffs at considerably higher temperatures than most of us. Running 100 mph takes about twice the horsepower as running at 70 mph, and all of that power is going through your gear boxes. About 5% of that power is lost as heat in the gear boxes, so 2x the power = 2x the heat. Cooling is better with the faster air flow, but probably not proportionately so. It would be interesting for you to take an inexpensive IR thermometer and measure the temperature of the tcase and rear diff immediately after about an hour at 90-100 mph. I'll bet it's well over 200 degF (~90C).

Given that extra heat, I would suggest running a good synthetic gear oil in your tcase and both diffs, and changing it every 30,000 miles or so. Your use would be considered "severe" by Toyota's standards, much like trailer towing, so check out those "severe service" recommendations in the owner's manual. Gear oil is cheap compared to tcase rebuilds.

[Jan777]

Thanks, good advise! Just yesterday I ran my T4R for 600 miles (950 km), 80% of it highway and all works perfect! In fact the most pleasant long distance vehicle I owned so far. Took me 10 hours 30 min, with 2 hours over bumpy roads and fields. The rest on the highway with about 90 mph on average.

Just a quick question: any online copy of this maintenance handbook? That "severe use" was so far not in my attention.

Well, loss of fluid will do it. Thanks for the extra facts - they explain a lot.

Because of your continuous high speeds, you are probably running your tcase and diffs at considerably higher temperatures than most of us. Running 100 mph takes about twice the horsepower as running at 70 mph, and all of that power is going through your gear boxes. About 5% of that power is lost as heat in the gear boxes, so 2x the power = 2x the heat. Cooling is better with the faster air flow, but probably not proportionately so. It would be interesting for you to take an inexpensive IR thermometer and measure the temperature of the tcase and rear diff immediately after about an hour at 90-100 mph. I'll bet it's well over 200 degF (~90C).

Given that extra heat, I would suggest running a good synthetic gear oil in your tcase and both diffs, and changing it every 30,000 miles or so. Your use would be considered "severe" by Toyota's standards, much like trailer towing, so check out those "severe service" recommendations in the owner's manual. Gear oil is cheap compared to tcase rebuilds.

[RonJR]

You can download it from Toyota. Click on this link Welcome to Toyota Owners and put in your year and model. You should see a "manuals" link that will allow you to access the various owner's manuals. Owner's manuals are free; if you want to access the service manuals you have to pay for a subscription - $amount depends on how long you want access.

There is a "Scheduled Maintenance Guide" that will be of interest to you. Look in it for "towing" and "special operating conditions" for recommendations. They actually recommend changing the diff oil every 15,000 miles if towing regularly, the tcase oil every 30,000 miles, and the transmission fluid every 60,000 miles.

"Lifetime" lubrication is only for the lightweight users, not for most of us.

Welcome to Toyota Owners

[joshuawhite1992]

Originally Posted by Jan777

not mine, just for info

Part number for the chain?? I am having a similar if not identical issue with my transfer case where it feels like it’s skipping when going up a hill or give it throttle.