Toy IFS 4WD Problem

Sorry I just know nothing about these and this is for a friend. Truck will not have traction at the front wheels of his 91 IFS Toy pickup. Has flanges instead of the auto 4WD hubs. T case appears to be working fine, there is a line that goes into the front diff. Is this some sort of vaccuum actuated mechanism? Engine was swapped out of one from a similar era 4 runner and was done half ass. Is there a way to test this or see or a real common problem area? Does this rely on engine vaccuum to shift so maybe there is a leak or part was not put back together properly?
 

KToy

Well-Known Member
Location
Herriman, UT
u say u have the flanges. but if the vacuum system is shot. get some ifs hubs and bolt them up and then lock them in.

if it works. walah. if it doesnt. you have a transfer case problem or your front end is messed.


id sya #$%^ it all as far as ifs and SAS the SOB.
 

94redtoy

short bus
Location
Salt Lake City
if it really has flanges like you said, then the front wheels are permanently locked all the time. the line you speak of that comes out of the diff is the breather. what happens is when the oil in the diff heats, it expands, and if there is nowhere for the extra air to go, then boom. its just basically an equalizer. as for your 4 wheel drive problem, check the driveshaft. if it moves in 4 wheel drive, then the t case is fine. this leads to another problem. maybe your ring and pinion in the front is shot, or a cv is broke. get under there and play around with everything. good luck.
 

Max Power

Bryce
Location
Sandy
I didnt know that toys had flanges for this model and year. The driveline test wont work if the hubs are premanently locked. If the shaft spins and the hubs are locked it doesnt mean your t-case is good. I would recommend unbolting your drive line and then see if your front yoke turns. If it does then its probably not in your frontend. Then see if the yoke on your t-case turns. If it doesnt turn there is your problem. Any more questions let me know.
 
The flanges might be from a later year. It also has taco wheels on it from the PO so they might have swapped the flanges. They are full time 4WD. I suspect it is the pneumatic / vaccuum system. I think the t case is fine but we will have to check. I told the owner to go exactly as instructed, 4WD and see if the front driveshaft is turning. Can't remember what the results were...
 

I Lean

Mbryson's hairdresser
Vendor
Location
Utah
There is a front axle disconnect on those trucks, they refer to it as the ADD system. (Automatic Differential Disconnect) Pretty reliable, but I think they are vacuum operated so a half-assed engine swap could definitely cause issues.

Hmmmm....maybe it's electrical instead? If it wasn't cold and dark out, I'd go look at my '94 MallRunner. If nobody's helped you out by tomorrow-ish, I'll go check it out. :D
 

DToy

Registered User
Location
Lehi
It's probably the vacuum actuator in the front axle. My wife's '91 4runner has a vacuum disconnect on the third member, there should be two vacuum lines running to the differential. Probably didn't get hooked up when the previous owner swapped the motors.
 
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