M37 Transfer Case "Woe Is Me"

Took the beast out for its 1st long run last Sunday. At speeds over 30 MPH the transfer case was screaming away and vibrating like a tuning fork.

Talked to John at Midwest and decided to purchase a new in the crate transfer case ($$$$$$).

Finished install late Friday evening and due to weather was not able to make a test run until late yesterday afternoon. Everything started off well, truck was quiet no vibration and she ran up to 45 MPH with plenty of legs left. After approx 15 minutes of driving at 40-45 MPH on a level straightaway, there was a loud pop and a chirp of rubber from the rear tires. Pulled over climbed under the beast and checked everything out. No leaking fluids, loose shafts, bolts etc .. even checked out the emergency brake as I wondered if it had somehow locked itself up.... all appeared to be normal.

Slowly drove back to the house, truck seemed to run alright but I kept the speed around 20-25 MPH. Storm was rolling back in so I put her away for the night and called it a day.

Took her out for a run this AM ..and after backing down the drive, put it into 2nd gear and she would hardly move. Seemed all bound up .. went thru the high low range and front wheel drive levers .. no difference .. finally after more RPM's she moved .. but I could hear clunking sounds from the transfer case and what sounded like squeaking. I am pulling my hair out at this point as this was a NOS Transfer Case dtd 1972.

All of my bearing are new, axles spin freely and the driveshafts have new bearings and no wobble when put togehter. Plenty of grease and all the correct oil and levels in all the componets.

I have decided to cancel my ALCAN Trip as I am scheduled to leave next Sunday and I don't trust my ride's drivetrain at this point!!! I left a voice mail for John at midwest, and hopefully will hear from him tomorrow.

What is it with the M37 TRANSFER CASE!!!

jack it up OFF all the tires, pull the drive shafts , see if both axles spin ( just because thay did before means nothing now) then see if the transfer spins, if that is good check the trans, not unheard of, of a trans doing this

Sorry about the trip, know you were REALLY jazed about it.

FYI, I emailed Midwest last week and got the "out of office" reply (War & Peace Show in England). It claims he will be back tomorrow, so good luck...

Number 1 -- you missed something, or you don't have a problem! Otherwise, on the new case, it sounds like you E-brake. Did you adjust that by the book? There is an important sequence to the adjustment. When the tires chirped, somethoing made them skid. Try the test again, see if the band/drum get hot. You have a winch on the tranny? Is it adjusted, Exactly, to be in Neutral with the lock-down plate?

Good Luck You have plenty of time to xix it before the Alcan. If worse comes to worse, take the truck to a "heavy truck shop" , and have their gear man look at it. That whole system is to simple too be too complicated. But the symptom you describe is the E-brake. Its too tight!

I swore I had a bad transfercase in my 37 so I replaced it with a nos from Midwest and the screaming got louder, turned out to be the spider gears in the rear diff were shot ( they fell out when I pulled the diff ) and the noise was carrying up through the driveshaft to the transfercase. just a thought

Thanks Moose, John did head to the UK last Tuesday ..

Rosco, no winch ... Will look at the emergency brake again .. used feeler gauge to check adjustment .. and used book procedure .. but its possible that I missed something..heading out to the shop to do some trouble shooting ..

After brake check and test run am going to look get her up off the floor, was thinking of dropping rear drive shaft and trying it out on front wheel drive to see if there is a noticeable difference (Thanks Bill/73M) .. would be great if all it was is the emergency brake!

Thanks for all the suggestions and help will get back to all on my results for the day .. most frustrating all of this!

While you have the rear tires off, pull the drums.

"pop"+ "chirp" sounds like brakes to me.
I've seen the "U" shaped retainer clips, and old rusted springs fail, fall off and wedge between the drum and shoe, and cause just what you described.

I went through a similar item, in my case it never was the T-Case, it was the rear diff., lost a tooth and has the same pop and skid then runs fine. The scream was the big issue, went the t-case route only to determine not actually where the sound was.

VPW sent a replacement rear member and all is now well.

JG ..not a rear brake issue, all new goodies ...just did a readjustment of brakes 2 weeks ago as they were "braking in" pun intended and I wanted t make sure the wear was even!

ST, If all else fails, will tear into that rear pumpkin next!

Rear axle yoke spins nice and free, pulled the rear shafts again, examined, no breaks or bad teeth at the ends. Dropped the rear drive shaft .. tried to drive the beast on the front wheel drive .. .. backed up ok but still bound up when going forward.

Dropped front drive shaft and then ran engine .. when trying to engage trany it was locked up to the point, that the truck was trying to stall out

Dropped the shaft between the trany and transfer case .. trany ran fine in all gears, no noise when turning .. ran in 4th gear at speed

Dropped the transfer case ... and now it turns freely by hand !@#$%^

Swapped out for a new transfer case this AM and I grabbed a spare trany.
Was going to install the new transfer case and just spin it up with the existing trany no drive shafts installed except from trany to transfer case and see what happens .. but on second thought, I think I'll just install the other trany and new transfer case and go from there ..

Results to follow!