M923 clunks

[Farmallmilitary]

Well today I was driving my m923 around and as I was starting to drive away it slowly stopped and clunked. It felt like something was binding up. I put it in neutral got out of the truck to see it I ran over something but there was nothing. I got back in, put it in drive, released the brakes and slowly drove away and it was fine.

So going into detail, I backed out of a parking spot and then started forward. I was not pushing the peddle at all just letting it kind of idle roll. About 100 ft from where I put it in drive it started clunking and slowed to a stop. Iam thinking it is probably transfer case related but my truck also has locking rear end and I was thinking maybe I snapped something? Who knows. I drove it home and it made no abnormal noises and it shifted just fine. I checked the bottom drain plug of the transfer case and there were no metal shavings or chunks. If anyody has experienced this please tell me what you found. I hope its nothing ba but by the looks of it, I may be in trouble.

 

[wreckerman893]

Have you checked the bolts on all the jackshafts and between the transmission and transfer case? You also need to check the bell housing bolts. When I was at Fort Benning we had two M932's and they were notorious for the bell housing bolts backing out. One of them almost lost a tranny due to all but one or two bolts backing out.

 

[Farmallmilitary]

I will check on that. Would the bell housings backing out cause binding up just going slow and not moving fast?

 

[Suprman]

If the driveline shifted because it was not bolted together tightly anything could happen its no different than bolts loosening up on a car and components becoming misaligned

 

[wreckerman893]

I will check on that. Would the bell housings backing out cause binding up just going slow and not moving fast?

If enough bolts get loose it can cause the transmission to twist and flex against the bell housing. I think this was even addressed in an issue of PM magazine. I don't know if they are posted on line anywhere. If so they would be an an issue from the 80's which is when I was at Benning.

 

[Farmallmilitary]

Ok so I checked out the truck including all the fluids, and they all seemed fine. No metal shavings which is good! I checked the bell housing which had not moved and I checked the driveshafts for play. All seemed fine. The only other thing I could think it may be would be the parking brake located behind the transfer case. Sure enough I could spin it and I heard a rattle in the drum. Anyways there has to be something wrong in there because there shouldn't be a rattle and I shouldn't be able to spin it with the parking brake lever engaged. This hopefully is the problem because if something was loose in the drum then it could sometimes catch and other times not. Will keep you uys posted on what I figure out.

 

[goldneagle]

Do you have enough tension in the line going to the parking brake? Did you test the parking brake with the spring brakes released (pushing the large button on the dash)? Mine was loose since they used the spring brakes to PARK the truck. You may need to tighten the knob at the top of the brake lever.

 

[Farmallmilitary]

I have tested the parking brake but it seemed that whenever I would try to tighten the knob it would hold the truck but in any position the the handle was in. Even if I tried disengaging the parking brake I would hear and feel a little drag in the brake. I have tried adjusting it alot but it doesnt seem to do both unless you twist the knob evertime you park it or drive it. It probably has a broken spring or something in there which would confirm my suspicions. I should have suspected the brake in the first place since it would not operate properly. Oh well.

 

[goldneagle]

I have tested the parking brake but it seemed that whenever I would try to tighten the knob it would hold the truck but in any position the the handle was in. Even if I tried disengaging the parking brake I would hear and feel a little drag in the brake. I have tried adjusting it alot but it doesnt seem to do both unless you twist the knob evertime you park it or drive it. It probably has a broken spring or something in there which would confirm my suspicions. I should have suspected the brake in the first place since it would not operate properly. Oh well.

Yep i think it's a spring too. The spring would pull the pads away from the drum when not engaged. Let me know if we are right about the spring.

 

[Farmallmilitary]

Will do!

 

[Farmallmilitary]

Ok so today I dropped the drive shaft to get to the parking brake and I will say that thing is heavy! I got the bolt off and then used a puller to get that other part off. I took the drum off and sure enough there was a loose spring in there or should I say the remanants of a spring. I took everthing apart and everthing else looks good. Thats why I couldn't adjust it the shoes where just resting on the drum. As I was taking the drive shaft out I noticed all the bolts where loose. Woops. They just weren't torqued down. So now I will go through the entire driveline and make sure everthing is torqued down just to prevent future problems.

I have one good spring and one bad spring. Can I just go to an auto parts store and get another spring that is fairly close? Do you think an auto parts store would have that sort of thing?

 

[wheelspinner]

IMHO NAPA is usually well stocked for that type of match-up./ Any of the others, if you can't put the year and model in the computer, pretty much 'deer in the headlights". If anything, I would try to get the original part number from the TM, there might be other issues besdies just the size, i.e. tensile strength, draw pressure etc that need to be involved.

 

[Farmallmilitary]

I went to napa to day and ordered the spring. 5-7 business days Oh well, while I wait for the spring I guess Im going to replace the oil seals on the transfer case since they are leaking a little. The trans to transfer seal and the rear output seal are the ones that are leaking. I assume it should be pretty straight forward.

 

[jonesal]

All the parking stuff is Merritor. I was able to buy the springs from a local truck parts stop including a new nut. Are you going to resuse the nut? Use locktite? The nuts were only about $10.

Al Jones
'84 M923 waiting to replace the transfer case rear seal...

 

[Farmallmilitary]

I was planning on using the nut again just with locktight. Is this suggested or not?

 

[jonesal]

One of the TMs says to discard it and use a new one, the other TM implies to reuse it. It is a prevailing torque nut and my training says to always replace if taken off. I also think the consequences of it loosening are catastrophic. The TM says to tighten the nut to 400 to 650 foot-pounds. Locktite's website doesn't say what it's good up to but I think asking threadlocker to hold to 600 foot-pounds is a bit much. My . I think it would be fine on other things, but that output yoke must take a lot of stress.

Al Jones
'84 M923

 

[Farmallmilitary]

So yesterday I was able to replace the seal on the input shaft to the transfer case. Trying to get the bolts out that hold the u-joint was a pain. I t was hard to keep it from spinning but finally I got it. I went to go get some new seals for the transfer but they only had 1 in stock. The other one will be here tuesday. I got some new nuts for the input and rear output at oriellys. All im waiting for is the springs and the seal and I will be good to go!

 

[pctrans]

Keep in mind that the "parking brake shoe and drum" behind the tranny is only a backup. Your maxi's on the rears are the primary parking brake.

 

[Farmallmilitary]

I know the maxi's are the main parking brake its just the springs in the parking brake were dragging and clunking and that was my problem.

Today I finally finished putting everything back together. Put the new seal in and new springs and torqued down the new bolt. I took it for a test drive and I heard no unusual noises but I will need to drive it more to be sure. I still need to adjust the parking brake but I think it will work.

 

[jonesal]

No pictures???

Al Jones
'84 M923