Does anyone know of an electric actuator conversion for these trucks? I am so tired of the vacuum it's not even funny. Got our first snow and had to take the truck cause I am having some issues with my car. Of course it starts doing the thing where it bucks and jerks cause the 4wd actuator isn't staying engaged when cruising, just replaced the actuator last year for the same issue, fixed it for almost a year. Before ya'll say get the manual posi lock kit, I did test fit one. Poorly designed, you hit your shin and foot on it non-stop since they designed it to mount hanging down from the dash.........right above the gas pedal, seriously. Also with the cam I have a lower vacuum signal. No I don't have the wild vents and have been through the vacuum system. My only other option is a vacuum pump, but as long as I am wiring things in, an electric actuator seems like the way to go. I have a couple big projects on my car I am going to do soon but after that if no one has any ideas I may get an shift housing and talk with our engineering dept about how to retrofit a solenoid in place of the vacuum actuator.

 

Could you mount the posi-lok thingy (technical term) to the T-case shift lever?

I found that even a slight vacuum leak causes havoc with the axle actuator. I went thru the entire vacuum system for it, (including a new actuator, and check valves....) and it has been trouble free since then. My engine is still stock though.... so, good vacuum signal. Vacuum pump seems kinda extreme...

I suppose another option would be an air COMPRESSOR. Use pretty much the same system, just use air pressure to move the actuator where you want it instead of vacuum. (regulated down to some reasonable level of course.) I figger 10 to 15 PSI should be more than adequate to the task, and having on-board air is never a bad thing on a truck.

And yet another alternative would be to pull the cad, pull the clips that hold the shift fork, set it up so it is ALWAYS engaged, put it back together, and never worry about it again. Might take a minor hit on gas mileage that way though. (which was the whole idea behind the cad anyway.....)

 

On board air would be nice, but since I got an Milwaukee M18 inflator that desire has been much less. I don't want a permanent lock as I eventually want to do an automatic locker up front. I also have a 4wd vibration which I discovered when I used it yesterday, which has made me more than upset since that front drive shaft has less than 4000miles on it.

 

I don't know if they even make an electric actuator for our front axles.... Somehow, an electric device that runs the risk of being submerged in water doesn't seem like a good plan to me.

Chevy used a thermal actuator for a while. Put it in 4wd, and it would run a current thru it, to warm it up, and engage the front axle. The only problem was, if it got snow packed up around it, (or even cold water....) it would disengage. Ooops.

Some variety of purely mechanical actuation seems like the best plan to me.... While the posilock may not be ideal, you could likely mount it somewhere more convenient??

 

The old gm thermal design may have been slow, but we had it on plow trucks. Worked fine in the snow. I did look at alternate mounting, the mechanism was so long and cable so stiff it was hard to route anyway other than what was directed. The new rams have electric actuators and with how many electronics are designed to be submerged I do think its possible to make. I cannot find an electric replacement anywhere. Just asking incase someone has.

 

How about adding a vacuum canister before the 4wd switch on the t-case? It might help to contain vacuum on the actuator.

 

Have you checked out the cad? If you don't have wild vents you should have enough vac to keep the cad engaged. May want to check out the metal lines that run from the cad back to the lines off the t case. Mine the fitting on the cad leaked and water got in and clogged/rusted it up.

 

I replaced the cad last spring and it solved the issue. I have not cleaned the hard lines or checked them yet this year. I am just over the vacuum at this point.

 

Personally, I would do the CAD delete.
I’ve put free-wheeling hubs on other 4x4’s and not really seen any MPG gains, so I can’t see it being much of a loss on these.
Put the 4x4 light switch on the transfer case where the vacuum switch currently is.

 

I had a 77 Chevy blazer with the NP203 (full time) T-case. When I got it, it got 11 mpg.... I bought another one for parts, that had a part time kit installed in the t-case, and locking hubs. Moved that over to mine. 11 mpg. Didn't matter if I was in 4x4 or not. Much to my surprise, it simply didn't matter WHAT I did, the Blazer got 11 mpg.... Just me, full of passengers, towing a trailer, loaded up for camping, cruising at 55, cruising at 75... It just didn't matter. I put a LOT of miles on that Blazer, on road, and off, under all sorts of conditions.... even took it swimming.... Some fun memories of that one..... (ask me sometime what my girlfriend at the time thought about it. )

Basically, I don't think the additional drag of a cad delete would make very much difference in overall MPG on these trucks. It is entirely possible you wouldn't notice the difference......