banging when engaging airshift

[Bill W]

I drove the deuce some more today with my new to me transfercase, I went and engaged the frt axle and got a lot of metalic banging and jerking/slipping as I was trying to get truck up a back slope into my barn., I have no idea how long this transfer has sat idle and I'm thinkin that sprags are a little frozon up??? I put air to the shift module before I installed the T/C and it locked in but obviously there other factors at work here and hopefully they are easy to cure ones.,
any input or direction to reference posts ( my search query didn't turn up much) regarding this problem would be much appretiated

 

[stumps]

Were you on pavement when you engaged the front axle? Because, banging, slipping and skidding are all part of the course if you did.

-Chuck

 

[Bill W]

I was slip sliding on wet grass/clay ( bed and inner wheels wre off truck so it pretty light back there) trying to get up into back side of my barn which has a nice slope to it

 

[stumps]

It should have been smooth and effortless. Check for loose U joint bolts and other things which may have been left undone during the install.

-Chuck

 

[gringeltaube]

There are no sprags in that air-shift TC, just a very robust dog clutch. The front half slides on the splined section of the front output shaft, controlled by the fork fixed on the shift shaft which is moved in (engaged) via the small air cylinder/piston and back out (dis-engage) by the internal coil spring.

You didn't activate that switch while the rears were slipping, or did you.....?

If that wasn't the case....... and nothing is seriously damaged or worn out your problem could simply be a sticking piston unable to complete the full travel for complete engagement.
Disassembling/inspecting/cleaning that part would sure help.

G.

 

[Bill W]

"You didn't activate that switch while the rears were slipping, or did you.....?"

No Truck was not moving when I engaged switch, I'll pull it ( module) and check for sticking piston, Thanks G

Thanks Chuck but I do know hows its suppose to engage, thats why I posted as I never had this happen with my last deuce ( avatar), , everything from re install is nice and tight

 

[Bill W]

OK
I jacked up the left front tire today and engaged the airshift, truckwas not running but I used remote air from my shop compressor hooked to the rear glad hand. I could turn the front tire by hand and feel it catch and release and catch and release over and over did not matter what dirrection I was turning tire it (Driveshaft) would not fully hook up., I turned up the pressure to 120 psi and still no lock up. I even put a air gauge down at the module on the t/c and found no restriction and could not here any blow by in the airshift cylinder. I could here the shaft clunking when I engaged air switch but thats was all she do so I'm thinking its had it. Any advice other then start looking for another T/C and while I'm on that note anybody in the Georgia area got one for sale??

 

[stumps]

It is also within the realm of possibilities that the axle spline is stripped out in one of your front axles. I couldn't tell from your description whether or not the front wheel was driving your drive shaft... It must ALWAYS.

Assuming that the wheel is driving your drive shaft, I would next drain the transfer case's fluid, into a clean pan, and check for debris. I would also take my finger and feel around inside of the drain hole for chunks of steel.

If the oil is clean, and there are no chunks, I would take off the air cylinder assembly, and bench test it.


-Chuck

 

[Bill W]

No
axle and diff are fine
I can hear all the noise coming out of the T/C ( engine not running)
I did put in fresh oil after install, old oil looked good and did not notice any metal parts falling out though I did not put my finger into hole but I'll take a look in there this week just for Sh!! & grins. As mentioned I can hear shaft engaging but it seems like its making a very short throw, to be a little more high tech its more of a clank then a clunk when I hit the air switch

 

[stumps]

I don't know if you have the manual showing the rebuild of the transfer case, but if not, it is available here:

http://old.steelsoldiers.com/index.php?module=pagesetter&type=file&func=get&tid=1&fid=file&pid=55

And the parts manual is available here:

http://old.steelsoldiers.com/index.php?module=pagesetter&type=file&func=get&tid=1&fid=file&pid=54

-Chuck

 

[Bill W]

OK
Its fixed
I dropped the T/C and pulled the frt drive housing and took a look at everything which all looked fine???, so I pulled the airshift module, turns out someone installed the airshift piston in backwards, when they did that the longer side of the piston now faces rear toward the T/C so now the shifter shaft has a shorter stroke/throw which in turn only gave a partial engagement of the clutch/couplings and since the seal is now reversed the clutch could easily kick out as I sure the air chanber could not hold strong enough air pressure to keep even a partial lock up, so a lot of re-do work but a happy ending as I have full lock up now
Stumps thanks again for the link to the TM's as I couldn't/wouldn't have been able to trouble shoot it without them

 

[stumps]

Great! That dog looks like new. I find stuff like that every time I break down, and let a mechanic touch one of my vehicles. They are in such a hurry to get the job done that they don't always think through what they are doing. It's a shame you had to drop the TC, but this time next week, when you are ripping up the ground with your smoothly working front wheel drive, that will all but be forgotten.

-Chuck

 

[DaveP]

once again the folks on this site come thru!

and thanks for the update.

 

[rizzo]

If that wasn't the case....... and nothing is seriously damaged or worn out your problem could simply be a sticking piston unable to complete the full travel for complete engagement.
Disassembling/inspecting/cleaning that part would sure help.

G.

 

[Bill W]

Yes G nailed it
but I would have never noticed the backward piston if I hadn't started from the inside out of the frt case as I was convinced it was something more drastic like a bent fork, broken set screw, alien abduction....

 

[gringeltaube]

Glad you found the REAL problem, Bill!
And sure enough next time this happens we will be inspecting for full dog clutch engagement by just looking through that oil fill orifice... before ripping all apart!
(Just learned something here.... Thank you!)

G.

 

[Bill W]

Actually there was a benefit to pulling the frt housing as I was checking things out I did not like the way the frt drive bearing felt/turned so I ended up swapping housings with my other T/C case as that bearing spun real nice. I did look through the hole before pulling the front housing and I could not find the set screw safty wire on the back clutch which gave me more reason to pull it, as it turned out the wire was loose and had slipped behind the clutch/dog