Okay, so the end of last winter I was having some problems with the 4wd grinding while I was driving. It seemed to partially slip out and go back in if I played with the shifter. The last time I used it, it totally started grinding bad and wouldn't stop until I shut off the truck and took it out of 4wd. I am having the vacuum checked next week and looking at the actuator, it's rusted real bad. Therefore I'm assuming at this point the actuator is shot and possibly I may also have a vacuum leak someplace.

In doing research, some replace the actuator and repair any line leaks, but there are many who have converted to the posi-lok system. Basically, I would like to hear from others on their opinion on replacing the vacuum actuator versus bypassing it with the posi-lok system. That is, pros and cons.

If all I have is a leak someplace, I'll go in that direction for now, but if the actuator is bad too, I need to make an informed decision on whether or not to replace the actuator or switch to a posi-lok system.

Looking forward to hearing from everyone ... thanks!

 

The cable system is hard to engage from what I hear. I recommend permanently looking the score together. You have 3 options
1. EMS OFFROAD one piece axle and CAD delete plate
2. Posi Lol makes one
Or
3. Do what I did for $0.10 lock it in permanently.

I change my CAD 3 times but it kept filling up with fluid and I always lost 4wd when I needed it.

 

I've been looking at vids on YouTube and just seen about the one piece axle. I haven't priced it out, but I can assume it's not cheap since you also have to change some inner parts due to a different spleen size. I also seen a vid on permanently locking the axle removing the actuator and replacing it's shaft with just a bolt and some nuts, which I'm assuming is what you did. This may be the way to go, but the guy in the vid said it may effect the truck at high speeds with a possible shimmy and will use more gas.

What's your take on that, that is, with the truck using more gas and a shimmy?

Right now my truck is getting 12.5 mpg avg in 2wd and in 4wd with some plowing, only 8.5 mpg. It's a 95 2500 with a v10.

 

The one piece shaft is $250 and just slides right in, it's the same spline.

Me I used a house clamp, but I don't have a shimmy and only lost .1 mpg as the 3rd gens don't even have a CAD on the 2500/3500 trucks. You aren't really using any more fuel as the transfer case is still in 2wd

 

I would just slide the collar over and permanently lock it.

 

Have you checked the front u-joint on front drive shaft? If it's dried out it could be part of the problem.

 

Where is the grinding coming from? The front axle, or the t-case?

 

I recently had both u-joints replaced on the front axle and I believe the mechanic checked the ones on the drive shaft. I can get under there once the snow stops (yup, we got snow today) and give another look.

I do remember that shifting into 4wd was really hard and sometimes I needed to shift back and forth to get it all the way in 4wd. The two guys I know who installed the posi-lok on their trucks said that after the install it got easier to shift into 4wd, but I'm not understanding what one has to do with the other since the shifter works the transfer case and the actuator worked off the engine vacuum.

 

Hmmm, now you got me wondering. From inside the truck, now that you say that, if I remember correctly, and it was way back around 8 months ago, I think it sounded like it was coming from where the shifter was. When I did some research, the only thing I came up with each time was that the actuator was losing vacuum causing the sleeve to partially slide back and cause grinding as it slowly slid off the one axle.

Now you have me wondering if it was actually coming from the t-case ...

I am having some work done on the truck this Tuesday and gonna do a vacuum check for leaks. The actuator looks really bad and totally rusted, so that was another reason I contributed the problem to the actuator.

This problem started out while I'd be driving in 4wd and I'd hear a grinding noise starting and then it would disappear. After a few times of that happening, I would need to slip the shifter out of 4wd and then back in and all was fine. The last time it happened, about 8 months ago, it started grinding really loud and no matter what I did it just kept grinding until I stopped and shut the truck off. Then I was able to shift back into 2wd and when I restarted the truck, everything was fine, as long as I just drove in 2wd. Haven't used 4wd since, but I'm having it checked out next week.

What in the t-case would do this while driving?

 

There is a snap ring on the output shaft, that holds things in place. If it breaks, or otherwise stops doing it's job, it allows the shaft to walk forward/back, and parts meet, that really shouldn't. I can make some truly horrible noises, that generally stop shortly after the t-case blows up.

It's easy to get to though. There may even be a cover you can pull to inspect it. Otherwise, drop the rear driveshaft, and pull the tailhousing off the t-case, and there it is. Or.... There it isn't......

If yours has abandoned shaft, look up "transfercase saver". A nifty product that solves the problem permanently.