Calling all QT experts

[memo43]

Ok so after a few times having to use my QT during all this awesome weather we are having in the Eastern Sierras, I still don't have a good warm and fuzzy.
I have a MM kit installed by the PO so I have been driving with the hubs in the locked position. When the road dictates I have engaged the QT, although I don't have any tire slippage I'm still not 100% sure my transfer case is engaged.
When should I use the flag shifter with the Qt engaged. my chero has struggled going up inclines covered in snow, as well as when I'm forced to park on snowy parking lots. almost as if the TC is not fully engaged.
I'm planning on jacking all four corners to verify the front tires spin with the TC engaged as well as replacing all the vacuum hoses.

questions is there a way to test or verify my switch is functioning, or where should I start.

here is where I started so far.

http://www.ifsja.org/forums/vb/showthread.php?t=178891

thanks in advance

memo

[wiley-moeracing]

The handle on the floor is for hi-low range and if the transfercase is stock will not make a difference in operation. the dial in the glove box is for the quadratrac to be in normal operation in one direction and emergency? transfercase locked operation in the other( only for stuck situations). you should check the operation of the dial in the glove box, make sure you are getting a strong vacuum signal from each port when engaged( may need a vacuum gauge to check. The dial may be leaking and not supplying full vacuum to the transfercase. if it works well then check operation of the diaphragm and see if it holds vaccum on both sides and moves the shaft. If that works then move to the shift fork in the transfercase, make sure the the e-clips did not fall out, they lock the shaft to the shift fork. Then inspect the shift forks to make sure the plastic pads are on the ends the of the shift fork that moves the interlock back and forth. If that looks good then you may have clutch wear on the cones, you will need to test that by using a torque wrench to see what the breakaway is before it starts to spin. This would be easier with the case out on a table of course. And full time 4 wheel drive does not mean will never be stuck, could be your tire choice also, icy roads, etc.

[joe]

On a 30+ year old car it's never a bad idea to invest in new vac hoses. It's cheap and at least eliminates one possibility. To see if your 4WD function is working, get on loose traction surface like some dirt, gravel, your lawn. Nail the go pedal then check if you have a tire scratch, one front, one rear. If you do then 4WD is engaged. 4WD is sorta a misnomer on most 4x4's unless you have some type of locker in the front and rear differentials. Without diff lockers all the tcase does is connect the front and rear drive shafts/differentials. With conventional open differentials on loose traction surfaces the power is going to the wheels with least resistance/traction. Those'll spin like crazy while the planted traction wheels just sit there and do nothing. If your MM PT conversion is working properly and 4WD is engaged on dry traction roads(not recommended!) you'll likely get some jumping or chirping from one of the front wheels in turns and in 4WD steering will be a lot stiffer on dry pavement. The mechanical H/L shifter should only be used in 4WD when Lo range is required off pavement. Shifting from H to L should be done when fully stopped or at very low' barely' rolling speeds. When shifting, shift firmly and deliberately no hesitations or you'll end up in neutral. I've had tired worn BW QTs with the MM conversions and to get in/out of Lo had to shut the motor down, then shift, then restart.
On a side note: if you're getting good vacuum pull to the switch from the vac reservoir. Pull the corresponding switch position vac hose from the vac motor on the case case and see if you have vacuum there. If you've got vac at both hoses at the vac motor could be the vac motor is toast. Not likely but it happens.

[memo43]

Joe thanks for the input,
I have replaced all the vacuum hoses and I now have a functioning TC, although I can hear a leak at the vacuum switch, but non the less everything is functioning.
I have placed an order at BJ's for a replacement switch.
memo

[bkilby]

Speaking of QT's, Mine has the MM part time kit and locking hubs. Right now the Jeep won't move without locking in the hubs. It did this once before and I put a hand vacuum pump on the diaphragm and moved it to where the Jeep can drive without locking the hubs. We recently connected the vacuum to the switch and tcase and now it won't move again. When putting that hand pump on the diaphragm yesterday, it will hold vacuum on the rear port but I can't build vacuum on the front port. Bad diaphragm?

I haven't looked inside this tcase yet so I'm trying to understand how it functions. I'm assuming that when you put vacuum to the rear port of the diaphragm, it moves the shift fork rearward making it 2wd. When vacuum is sent to the front port, it moves the shift fork forward and engages the front output shaft. Is this correct? What would cause the tcase to put power to the front but not the rear?

[wiley-moeracing]

you will need to pull out the transfercase and dissasemble, you have stripped splines or snap rings on the diaphram that have failed. a good time to rebuild and its easy.

[memo43]

Mine ended up being the retainer spring that holds the vacuum diaphragm,
I must have boogered it up when switching the vacuum diaphragm.
I did the knee jerk reaction and replaced it with a full time case.
I will eventually rebuild the older one. especially since it has the mile marker conversion, that an had excessive chain slack.