How To Lock Central Diff

[fernandolpa]

From time to time I go offroad with my RX. Not very heavy stuff but some times I hit mud and sand, and I would like to lock the central diff for better traction.

Actually the VSC and the traction control stops too much the car when you need some speed and power (climbing a sand hill or diriving by mud).

I have a video on youtube under rx300. Ok my brother in law is not the beast camara holding man...

Also when I left on rear wheel on air, the ETC makes a lot of noise and wheel still spins...until you use the parking brake to stop it, then traction comes back and moves the car much better.

Any ideas wellcome!

...except of course like "buy a land cruiser" or something similar. I really love my RX even whit the speed limiter at 110 mph...but that one is a different history.

[wwest]

From time to time I go offroad with my RX. Not very heavy stuff but some times I hit mud and sand, and I would like to lock the central diff for better traction.

Actually the VSC and the traction control stops too much the car when you need some speed and power (climbing a sand hill or diriving by mud).

I have a video on youtube under rx300. Ok my brother in law is not the beast camara holding man...

Also when I left on rear wheel on air, the ETC makes a lot of noise and wheel still spins...until you use the parking brake to stop it, then traction comes back and moves the car much better.

Any ideas wellcome!

...except of course like "buy a land cruiser" or something similar. I really love my RX even whit the speed limiter at 110 mph...but that one is a different history.

First, I would disable the VSC/Trac system by disconnecting and then reconnecting the MAF/IAT sensor. Disconnect with the engine idling, the engine will die, reconnect and restart. The VSC/Trac system will then be disabled for the next few drive cycles. Assuming your's is actually an RX300, not a 330 or 350, you have a VC, Viscous Coupling, across the center diff'l that will tighten the coupling coefficient between front and rear drive but only after a few seconds of desparate F/R wheelspin/slip.

The only disadvantage of the above is the loss of the "virtual" rear LSD, assuming that firmware actually exists in the RX300.

Mine is an '01 AWD RX300 and I fully expect the trnasaxle to fail prior to 100,000 miles. At that point I will DIY the overhaul, remove/toss the the center diff'l front drive side/spider gear and weld the rear drive side/spider gear in place. I will then have a SOLID drive coupling to the rear and a "soft", VC, coupling to the front. It would be nice if I could find a quicker reacting VC but that's likely beyond my reach.

Florida and yet the RX picture is of one from "off-shore"...??

[fernandolpa]

From time to time I go offroad with my RX. Not very heavy stuff but some times I hit mud and sand, and I would like to lock the central diff for better traction.

Actually the VSC and the traction control stops too much the car when you need some speed and power (climbing a sand hill or diriving by mud).

I have a video on youtube under rx300. Ok my brother in law is not the beast camara holding man...

Also when I left on rear wheel on air, the ETC makes a lot of noise and wheel still spins...until you use the parking brake to stop it, then traction comes back and moves the car much better.

Any ideas wellcome!

...except of course like "buy a land cruiser" or something similar. I really love my RX even whit the speed limiter at 110 mph...but that one is a different history.

First, I would disable the VSC/Trac system by disconnecting and then reconnecting the MAF/IAT sensor. Disconnect with the engine idling, the engine will die, reconnect and restart. The VSC/Trac system will then be disabled for the next few drive cycles. Assuming your's is actually an RX300, not a 330 or 350, you have a VC, Viscous Coupling, across the center diff'l that will tighten the coupling coefficient between front and rear drive but only after a few seconds of desparate F/R wheelspin/slip.

The only disadvantage of the above is the loss of the "virtual" rear LSD, assuming that firmware actually exists in the RX300.

Mine is an '01 AWD RX300 and I fully expect the trnasaxle to fail prior to 100,000 miles. At that point I will DIY the overhaul, remove/toss the the center diff'l front drive side/spider gear and weld the rear drive side/spider gear in place. I will then have a SOLID drive coupling to the rear and a "soft", VC, coupling to the front. It would be nice if I could find a quicker reacting VC but that's likely beyond my reach.

Florida and yet the RX picture is of one from "off-shore"...??

Actualy I am from Spain, living in Canary Islands. I open my log as from Miami beacuse I travel there oftenly.

Of course picture is not from FL, is from Canary Islands. I have more on ud and over the mountains here, but is an island, so there is much roads for off roading.

I am very close to Africa, 60 miles, but I don't think that the RX is the appropiatte machine for desert roads or sand.

I've been roading there in a Montero, from Dakar to Banjul (Gambia).

Driving a Lexus in Africa is like a stupid searching for troubles.

My RX is also a AWD RX300 european version, made in Japan. Nobody knows here what kind of trans I have, if I have central and rear limited skip diff or only the trac control by braking the wheels. Beive it or not, thats why I enter the US forum. Now I know more from my car than Lexus dealer. Have in mind that they sold 10 units total from 2000 up the new model...

Do you think that playing with the MAF/IAT can cause future problem on trans or engine managing?

And just to finish, the trans problems occurs in all RX?

Thanks and best regards from SPAIN

[wwest]

From time to time I go offroad with my RX. Not very heavy stuff but some times I hit mud and sand, and I would like to lock the central diff for better traction.

Actually the VSC and the traction control stops too much the car when you need some speed and power (climbing a sand hill or diriving by mud).

I have a video on youtube under rx300. Ok my brother in law is not the beast camara holding man...

Also when I left on rear wheel on air, the ETC makes a lot of noise and wheel still spins...until you use the parking brake to stop it, then traction comes back and moves the car much better.

Any ideas wellcome!

...except of course like "buy a land cruiser" or something similar. I really love my RX even whit the speed limiter at 110 mph...but that one is a different history.

First, I would disable the VSC/Trac system by disconnecting and then reconnecting the MAF/IAT sensor. Disconnect with the engine idling, the engine will die, reconnect and restart. The VSC/Trac system will then be disabled for the next few drive cycles. Assuming your's is actually an RX300, not a 330 or 350, you have a VC, Viscous Coupling, across the center diff'l that will tighten the coupling coefficient between front and rear drive but only after a few seconds of desparate F/R wheelspin/slip.

The only disadvantage of the above is the loss of the "virtual" rear LSD, assuming that firmware actually exists in the RX300.

Mine is an '01 AWD RX300 and I fully expect the trnasaxle to fail prior to 100,000 miles. At that point I will DIY the overhaul, remove/toss the the center diff'l front drive side/spider gear and weld the rear drive side/spider gear in place. I will then have a SOLID drive coupling to the rear and a "soft", VC, coupling to the front. It would be nice if I could find a quicker reacting VC but that's likely beyond my reach.

Florida and yet the RX picture is of one from "off-shore"...??

Actualy I am from Spain, living in Canary Islands. I open my log as from Miami beacuse I travel there oftenly.

Of course picture is not from FL, is from Canary Islands. I have more on ud and over the mountains here, but is an island, so there is much roads for off roading.

I am very close to Africa, 60 miles, but I don't think that the RX is the appropiatte machine for desert roads or sand.

I've been roading there in a Montero, from Dakar to Banjul (Gambia).

Driving a Lexus in Africa is like a stupid searching for troubles.

My RX is also a AWD RX300 european version, made in Japan. Nobody knows here what kind of trans I have, if I have central and rear limited skip diff or only the trac control by braking the wheels. Beive it or not, thats why I enter the US forum. Now I know more from my car than Lexus dealer. Have in mind that they sold 10 units total from 2000 up the new model...

Do you think that playing with the MAF/IAT can cause future problem on trans or engine managing?

No, not as I suggested and I assume only on a rare basis. I was actually advised of the procedure by the service manager at Bellevue Lexus.

And just to finish, the trans problems occurs in all RX?

Yes, but not in the same manner for all models, Toyota made year to year changes, fixes, to try and solve the problem.

99-00 results in premature transaxle failures due to low line pressure when shifting with the engine at, or having just previously been at idle.

01-03 results in burned ATF in as little as 40,000 miles due to increased ATF pump size tried as a fix.

04--- results in 1-2 second downshift delay/hesitation to allow time for ATF pump to build up line pressure with the engine at idle.

Thanks and best regards from SPAIN