very perplexing axle question

[Monster Man]

I decided to start a new thread on my axle question.

so, when I had my brother watch for the wheels, we got her stuck on a boulder and was in first low range, or maybe it was second, not sure.

so we got stuck and the rears were both spinning freely for traction, the fronts were rocking back and forth a couple inches each but not spinning on one side or the other. SO we got home and popped off both flanges, they look good. Spin one (with both on the axles but not bolted to the wheels) and it spins the other in opposite direction, hold pressure on one and it spins the driveshaft, and vice versa. Bolt both up to the wheels and I stuck some bolts in the front power output on the axle and pried on it and it moved the truck back and forth. SO, I am fairly certain that everything is good on the axle side. My only thought is something is slipping in the t-case, but the shaft was spinning when the wheels weren't which REALLY has me confused. Now you mention about the sprag engagement through first, could you explain that some more? What do I need to do to get it engaged? I've just been driving it like I thought was normal, starting in second, going from reverse to second, etc. Whoops!

 

[Desert Rat]

MM;
The sprag is a spring type engagement within the transfer case. The theory is when the rear axles start to spin 1/4 turn the sprag will put power to the front axle from the tension in the spring. However, this thoery does not always work in reality. There have been cases where the sprag will drop in when the truck is on the highway in fifth gear and force the transfer case to engage. This is very hard on the fifth gear cog. Over time the cog will fail. In other instances the sprag will partially function in low first and cause the front axle not to gain full power. Thus the apparent and true observation power is getting to the front but seems ineffective. You may also have problems with the hoghead from the u-joint on forward. Either way it's not an easy or pretty picture. But the good news is youi can modify the t-case to air and gain full power once all the "measurin' an' cipherin'" is done<img src="emoticons/icon_smile.gif" alt="Smile">. Let me know how it goes because I'm getting ready to do the same job on my 109 too!

 

[Dieselsmoke]

Sounds like the sprague is out of adjustment

 

[Recovry4x4]

Man, wish y'all were around here. I had an airshift in the back yard for years! Just traded it for some Reese Cups. As far as shifting, the first/reverse shift rail protrudes out of the back of the trans and connects through a linkage assy to the sprag. This neccesitates that you must go through first gear when changing directions. Not to be too harsh on your observer but I would get another person to have a looksee at that. He may have not been watching both tires. If the front driveshaft was turining and one of the wheel end was not, the noise would have been obvious. The exception to that would be a broken axle and you eliminated that theory buy spinning the wheels while off the ground. Confirm with another observed before getting to deep into teardown.

 

[Monster Man]

Originally posted by Recovry4x4

Man, wish y'all were around here. I had an airshift in the back yard for years! Just traded it for some Reese Cups. As far as shifting, the first/reverse shift rail protrudes out of the back of the trans and connects through a linkage assy to the sprag. This neccesitates that you must go through first gear when changing directions. Not to be too harsh on your observer but I would get another person to have a looksee at that. He may have not been watching both tires. If the front driveshaft was turining and one of the wheel end was not, the noise would have been obvious. The exception to that would be a broken axle and you eliminated that theory buy spinning the wheels while off the ground. Confirm with another observed before getting to deep into teardown.

you are absolutely correct, this morning before work I got stuck again to have my bro look exactly for what was turning- he wasn't sure yesterday, but today we confirmed the driveshaft wasn't spinning. So, it's good news everything in the axle is OK, bad news the t-case isn't OK <img src="emoticons/icon_smilie_bitchin.gif" alt="Bitchin">

I'll start diggin through my manuals on how to adjust this thing and getting a feel for it, thanks for all the help.

There are some givens- I will be adding on my front flanges and disconnecting the driveshaft, shoot if I haven't got stuck yet in 4 wheel drive I probably won't, right? Well, don't say that, but you know what I mean. Thye 4 wheel is fine for now and will save gas with the axles disengaged.

Now, I'm going to start gathering components for the air swap. Any help with that would be great- which manual has diagrams of the two cases, preferably side by side?

Any component lists of exactly what I'll need? This is all new to me but I'm eager to learn! Thanks for the help guys <img src="emoticons/icon_smile_big.gif" alt="Big Smile">


P.S. one thing I forgot to mention but is relevant now is that my t-case is leaking front AND rear, theonly thing on the truck that leaks is that dang t-case <img src="emoticons/icon_smilie_bitchin.gif" alt="Bitchin">

 

[Monster Man]

also, you mentioned about first gear low malfunctioning, true enough I had it in first low when testing. Should I try second low or first high to see if it goes in? Is there any sort of sequence I have to go through for it to work properly. I went from low reverse to low first to be sure but it wouldn't spin this morning

 

[Monster Man]

for those that are interested, Alex at IMP informed me of a shift kit that Memphis equipment Co. sells that converts the sprag in your M35 transfer case to a series of gears allowing you to manually shift it. SOunds like a very neat option, as even the airshift has a chance of malfunctioning (notorious on lighter 4wd's). That's why I like my NP205 so much, if I could get this case with a nice solid shift setup that would be great. The kit price is almost the price of a takeout airshift, but you also have to factor all the airlines and switches and freight on the new t-case so this kit sounds like a good option right now.

Are the two cases the same, just with different front ends, ie, are they both beefy enough?