Vacuum Shift Transfer (HJ61) troubleshooting (1 Viewer)

[AussieHJCruza]

So...I've had a bit of a search and can't seem to find anything definitive; apologies if this has been covered already...

But, having no success getting the HJ61 into 4wd, low range lever shifts into low, hubs actuate properly and so on, but the 4wd dash light doesnt come on and front axle doesn't seem to be engaging.

My understanding of the system is, pushing the H4 button applies vaccum to one side of the actuator on the side of the transfer, and when it moves to physically engage the front axle, the light will come on. When the button is released, vacuum is applied to the other side and disengages 4wd, at which point the light goes off.


I'm just wondering if anyone could give some advice on how I should approach the troubleshooting procedure to get this working as it should

Thank you in advance

 

[mongoose2231]

Well, the 4 low is manually actuated so the front axle should engage. The vacuum actuator is for 4wd high only. If the light doesn't come on it doesn't necessarily mean you have no 4wd. Best bet is to have some one check under the truck if the vacuum actuator moves the transfer case rod that engages 4h. If that doesn't happen, then the solenoid controlling the vacuum switches may be bad. Or you have a vacuum leak. They are expensive to get, however different ones from newer model Camrys I think, can have their wiring modified to make them work. On the other hand, someone here in the forum did a great write up about installing a 5way vacuum valve and did away with the electrics controlling the vsv's entirely. Now if I could only remember that thread...

 

[AussieHJCruza]

I was under the impresion that the 4wd in Hi and Low was done by vacuum, the lever only shifted between lo and high range. On my old HJ60, when you moved the lever it engaged the front axle too but I always presumed there was a switch or something that activated the vacuum solenoids when low range was selected.

Possibly I should have learnt about it when I had a functioning system in front of me, but it always just worked so...

 

[stockhorse]

Do you have chassis and body repair manual. I am in Qld and will email you the relevant section for diagnostics if you don't have it.
You can check the VSV's by swapping the lines to them around. if you have a faulty one it is the easiest way to diagnose it.

 

[AussieHJCruza]

I have got them somewhere in the mass of stuff (Moving house does that), but if you could email the relevant section, that would be excellent.

I'll flick you a PM

Cheers!

 

[stockhorse]

How did you go with this?

 

[DirtRoads]

I was under the impresion that the 4wd in Hi and Low was done by vacuum, the lever only shifted between lo and high range. On my old HJ60, when you moved the lever it engaged the front axle too but I always presumed there was a switch or something that activated the vacuum solenoids when low range was selected.

Possibly I should have learnt about it when I had a functioning system in front of me, but it always just worked so...

That is exactly how it is done on an FJ62, no clue what the difference is on an Hj61. On an FJ62, you can locate the vacuum solenoids on the passenger side of the firewall. When you find them, just move the vacuum lines around to see if you can attain engagement. In doing so, you should be able to isolate which (if any) solenoids are jacked up.

 

[WJB4000]

The way I diagnosed mine was start the truck up, get under and see which line has vacuum on it in 2wd. Then pushed the button to see if it switched vacuum to the other hose. Mine did not, and assumed it was the vsv on the firewall since they fail all the time. Come to find out, my vsv's were fine and it still wasn't switching vacuum. So I started following my vacuum lines down from the vsv's to the transfer case. They change from rubber to metal and back to rubber several times before they get to the transfer case. I pulled each connection apart and checked for vacuum at each interval. Eventually I found that there was a blockage of dirt in the metal section of line directly in front of the transfer case. That section of metal line changes from the tiny sized vacuum line to a larger vacuum line and ends at the transfer case. My clog was right where the step up is in the metal line. I just took a drill bit the correct size and put it in the hole and started turning it by hand until it got all of the crud out of there. Then took my air hose and blew the rest of it out. Now my 4wd works perfectly every time I push the button.

Heres the thread I started on mine when I was having my problem...

FJ62 vacuum diaphragm kit?

 

[AussieHJCruza]

Sorry for the delayed responses; been flat out with other things I'm afraid.

So...swapping the vacuum lines heading to the transfer on the solenoids shifts her into 4wd, light comes on and front driveshaft is locked. So I'm guessing I've either got a dead VSV or not getting power as it should, which wouldn't be suprising given the interesting electrical work on this truck...

 

[KlickitatPhil]

The way I diagnosed mine was start the truck up, get under and see which line has vacuum on it in 2wd. Then pushed the button to see if it switched vacuum to the other hose. Mine did not, and assumed it was the vsv on the firewall since they fail all the time. Come to find out, my vsv's were fine and it still wasn't switching vacuum. So I started following my vacuum lines down from the vsv's to the transfer case. They change from rubber to metal and back to rubber several times before they get to the transfer case. I pulled each connection apart and checked for vacuum at each interval. Eventually I found that there was a blockage of dirt in the metal section of line directly in front of the transfer case. That section of metal line changes from the tiny sized vacuum line to a larger vacuum line and ends at the transfer case. My clog was right where the step up is in the metal line. I just took a drill bit the correct size and put it in the hole and started turning it by hand until it got all of the crud out of there. Then took my air hose and blew the rest of it out. Now my 4wd works perfectly every time I push the button.

Heres the thread I started on mine when I was having my problem...

FJ62 vacuum diaphragm kit?

I was troubleshooting my slow-to-engage 4WD this evening and started where you found your clog. I had to lick my finger to even detect the vacuum down there. Traced it back to the vacuum pump (2H diesel, has a vacuum pump) and it was the first rubber line coming off of it. Removed the rubber line and could barely blow through it. Massaged the line and grabbed the nearest solvent I could find (Windex) and worked the clog out. Now I've got 4WD in seconds instead of minutes! I'm going to buy several feet of vacuum hose tomorrow and replace everything within reach.

Thanks for the lead, perhaps the next guy will appreciate this finding!