2nd Gen Non-Engine/Transmission 2wd low range manual lockout

[KRStone]

I read somewhere in TDR that using this type of a setup is not for rough terrain, only backing up trailers and such.



Now, I don't do rock crawling or Baja 500 in my truck, but I do a lot of backcountry road driving. I would like to use the low range in 2wd to save my brakes and make the road less bumpy



Any thoughts about this warning (I can't quote the location of the info, I only remember it).



KRS

 

[Missouri Mule]

KRStone,what the manual lockout is a vacuum switch that keeps vacuum going to the axle fork(which is operated by vacuum). There are two vacuum hoses that go to the shift fork, the switch intercepts the the vacuum going to the engage part of the switch.

I don't see why you can't drive it forward over ruff terrain if forward gears unless there is a possiblity of knocking a chain loose inside of the transfer case.

My land lady's son pulled a semi full of sod a mile and half in two wheel low with a ford power stroke, of course they have locking hubs.

 

[BarryG]

I cant think of a reason not to do as you want as long as the proper method is used (ie that the vacum is redirected and not just dumped to keep the cad from engaging so it will not slide back and forth) Or another method is to use the posicable system or whatever it is called that replaces the cad vacum system with a cable actuator. One other thing to remember is to be careful using the go pedal in 2low as you are no longer splitting the power between axles and all that torque/hp going through low gearing to one axle could be bad juju if not careful however careful driving with that in mind should not be a problem (imo).

 

[KRStone]

Good points.



I'll have to see if I can find the reference and post it, just for good measure.

 

[Missouri Mule]

BarryG, your right the switch redirects the vaccum to keep the fork from engaging. I remembered that later after I went to work.

 

[AClayton]

The BD kit is sold at Geno's for a bit over a $100 bucks. I installed mine for going up steep grades pulling a heavy trailer at slow speeds... ..... it makes it so much easier on the transmission. But as suggested, our Cummins' deliver max torque at low rpm and this kit puts it all right there to use. Be very careful with throttle input while in this gear as your rear axle and driveshaft are no match for the insane torque that is available.



Alan

 

[JMcCoy]

Get the cable kit from Posi-lok. The vacuum CAD is garbage. The vacuum diaghram is the weak link of the weakest link of our trucks. The cable is still crap, but it is 100% better than the vacuum actuator. They are best left to operating A/C vents.

 

[WilsonF]

My "garbage CAD" has lasted me 14 years and 200K miles, I wish all the parts on my truck were garbage like that.

Floyd

 

[CKelley1]

mine lasted nine years, i did not find out about posi-lok untill after we had installed the CAD and with pulling very heavy loads with it there has never been a issue with the transfer case we use the first two gears in low range to get started and to go down steep grades and backing trailers. the 2000 has about 400,000 miles on it.

 

[Extreme1]

I've got a Bob V switch on mine, it's a vacuum switch, no electrics. Works great and cheaper than the BD kit. Not sure if it's still available though.

 

[JMcCoy]

The CAD is acceptible for backing horse trailers and pulling a boat up a slippery ramp. No offense to anyone here, but if you do any "real" off road driving, it will fail. I'm not talking rock crawling. I mean finding back woods hunting, fishing, or, camping spots. Even Dodge and Jeep realized the CAD was a huge mistake. Ford and Chevy sure never jumped aboard. They just sat back and laughed at us.



Mine has failed three times, and I go easy on it. The last time it failed, I was in south Florida muck. Your beloved CAD failed and I lost 4WD. If anyone has had experience with Florida muck, they know the longer you are stuck, the more you sink. Water entered the transmission pan through one of thoughs POS B&M drain plugs. That cost me a transmission. It sounds to me that KRStone is intending on doing a little more than backing trailers. I understand if the cable system was not available, but it now is. I'm not even going to get into my feelings about the axle portion of the CAD and the 30 spline Dana 44 axles in them. I will save that for another rant.

 

[CKelley1]

jmccoy i agree. i went back with a cable. once you take the diaphragm off and see how mickey mouse it is it is a wonder that it works as long as it does. and the vacuum lines will come loose by the fender and you not know it until you are stuck in the mud or snow. really messes up your day.

 

[AABEN]

Get the cable kit from Posi-lok. The vacuum CAD is garbage. The vacuum diaghram is the weak link of the weakest link of our trucks. The cable is still crap, but it is 100% better than the vacuum actuator. They are best left to operating A/C vents.

I would like to have the web site for the Posi-lok == thank== Ben

 

[WilsonF]

Just Google it.

4x4 Posi-Lok - 4WD Engagement Systems

Floyd