thelasteaglescout

Folks,

My 4wd hasn't been engaging for months. The dealership said it was an issue with the:Solenoid Assy, Four Wheel Drive Control (Toyota Part#: 85440-35040). So I finally make it over to the local junk yard and purchase two for $10 vs. $1000 from the dealer. Installed them, same problem. The green 4WD light will flash then go out. My "new" used valves came with what appears to be a "check" valve of sorts Blue with black on one end and white on the other. I decided I would try changing it out just for the heck of it. Nothing. Then I wondered, what if I reverse this little check valve. Bingo! I now have 4wd working as it should. Shifting in and out, everything seems great. BUT, I'm worried as I feel I must be robbing peter to pay paul by reversing that valve.

Any idea what I've done and what I could be screwing up using my runner this way. Ignorance is bliss. '97 4Runner, single owner, 220k miles.

Thanks!

thelasteaglescout

One other note, I had the transfer case seal replaced a while ago and never thought to test the 4wd afterwards. When I finally got around to checking it, it didn't work. So, I don't know if it's related, but makes me wonder if vacuum lines were swapped somewhere. Thanks again for your thoughts.

TheDurk

No, I think the check valve was just in backwards. It really wouldn't work backwards at all, but no harm would be done. No vacuum would reach the VSV, and hence the actuator, if the check were good. If it were bad, it would work half-assed.

To check the check valve, pull the valve and blow through each end. Only one way should work. Correct installation is so air can only flow towards the manifold. It should be installed between the engine manifold and the little 4-way connector that also goes to the two VSV's and the reservoir.

As to the seal, no vacuum lines go to the transfer case, or even near it. They go to the front diff. What they could screw up (and have in my case doing a clutch job), are the connections to the detection switches on the T-case. It is easy to crush them or just leave them loose on a seal job when you separate the T/C from the transmission, assuming you meant the input shaft seal.

thelasteaglescout

First, TheDurk, thanks for taking the time to reply!!

After my success yesterday getting the 4WD in gear by reversing the check valve off of the manifold, I decided I should follow up with the dealership again who had previously charged me $86 to diagnose that my VSV's were not working correctly and see if they had any feedback on my new revelation of the check valve. They agreed to look at it one more time with my new information. Turns out my suspicions were right all along; when they had replaced my rack & pinion (took three tries….another long story) they had somehow reversed my vacuum lines that were in route to the transfer case. By my reversing the check valve it somehow allowed the VSV’s to work as designed and highlighted an issue elsewhere! Craziness! I don’t really believe in luck and hedge more towards divine intervention. BRING ON THE SNOW, TheLastEagleScout is now “prepared!”

Hope this may help someone else one day!

By the way, I now have two very used (junkyard), but apparently functioning VSV’s if anyone ever determines they need one.

TheDurk

Again, the lines go to the front diff, not the transfer case, and that is why you could mess them up working on the R&P, as opposed to the T/C seal, which would be difficult. Reversing the hoses would basically mean you would never have 4wd as the diff would engage when the t/c would not, and vice versa. Reversing the check valve as well would create a mess that would work randomly, if at all. Moral of the story: dealers can really screw things up.

Have fun in the snow.