Is this Normal? M818 crashing noise in reverse.

[NovacaineFix]

Hello. Sorry for the baiting title but I'll have to try my best to explain it as I don't have video of this noise as it occurs.

I was driving my 818 around the neighborhood the other day when I heard this crashing noise as if I hit a car behind me. I was backing the truck in when this happened in reverse in high gear. It had happened one time before and the only thing I can remember that is the same was that I had previously had the transfer case in low gear prior to switching to high gear when it made the noise. Same intensity of the noise, where it sounds like you just backed into a parked car or something metal and heavy.

Nothing was behind me, the area was clear. Nothing on the truck appears to be broken or out of place, and everything works with nothing leaking.
I drove it today without putting into low gear and no noise at all.

So my conclusion, without taking anything apart, is that it is the transfer case? But it drives fine.
I was wondering if this is a normal noise of maybe the low gear shifting into high? If so, is this something I should look at before it breaks something?

This truck sat for probably 8-10 years before I got it a little over a month ago. I have put nothing into it, so far, but batteries and fuel.

The engine looks to be brand spanking new, with no leaks or oil residue from use, so my gut feeling is that something is sticking in the transfer case when shifting from low to high, but that is just a guess.

Any ideas?

 

[pmramsey]

I believe the manual states that one must not back up while in low range. I have never backed up my M818s in low range.

 

[NovacaineFix]

I believe the manual states that one must not back up while in low range. I have never backed up my M818s in low range.

Now since you mentioned that, I do recall reading part of the manual that stated something like that. That means I must "really" re-read the manual so I don't break anything.

I think what happened, was that I was going through the gears to get a feel for everything and I left the transfer case shifter in the down position before I shifted into reverse.

 

[MyothersanM1]

M809-series trucks (including the M818 ) may go in reverse in low range transfer. It's the M939-series which have complications in low range reverse. Do a transfer case flush and see if it clears up the issue.
Here's a couple threads pointing you in that direction...
http://www.steelsoldiers.com/showthread.php?86973-cleaning-out-transfer-case-with-diesel
http://www.steelsoldiers.com/showthread.php?26722-Transmission-amp-Transfer-case-flush

 

[SWMARTINA]

found this in the archives:

2) The sprags in the transfer case are controled by the shift valves (poppets) located in the shifting tower of the transmission. In any forward gear or neutral the forward sprag is engaged and the reverse sprag is only engaged when the shifter is in reverse. Never allow the truck to roll back with the transmission in neutral or any forward gear. A transmission change to a non-stock unit would require some type of shifting system to keep the transfer case engaged like the stock system. This is just one problem for an updated transmission installation in these trucks.

 

[73m819]

Check your upper rear torque rod, if the insert came out of the rod, it WILL allow the rear axle rear drive flange hit the rear cross member because the axle rolled back, this sound you describe is the sound you will get.

 

[Csm Davis]

I believe the manual states that one must not back up while in low range. I have never backed up my M818s in low range.

Wrong truck the 809 series can go into low without problems in forward or reverse with or without a load.

 

[Csm Davis]

Hello. Sorry for the baiting title but I'll have to try my best to explain it as I don't have video of this noise as it occurs.

I was driving my 818 around the neighborhood the other day when I heard this crashing noise as if I hit a car behind me. I was backing the truck in when this happened in reverse in high gear. It had happened one time before and the only thing I can remember that is the same was that I had previously had the transfer case in low gear prior to switching to high gear when it made the noise. Same intensity of the noise, where it sounds like you just backed into a parked car or something metal and heavy.

Nothing was behind me, the area was clear. Nothing on the truck appears to be broken or out of place, and everything works with nothing leaking.
I drove it today without putting into low gear and no noise at all.

So my conclusion, without taking anything apart, is that it is the transfer case? But it drives fine.
I was wondering if this is a normal noise of maybe the low gear shifting into high? If so, is this something I should look at before it breaks something?

This truck sat for probably 8-10 years before I got it a little over a month ago. I have put nothing into it, so far, but batteries and fuel.

The engine looks to be brand spanking new, with no leaks or oil residue from use, so my gut feeling is that something is sticking in the transfer case when shifting from low to high, but that is just a guess.

Any ideas?

This sounds like the Sprague not operating properly

 

[ClintA]

I would drain the Transfer case and fill it with clean diesel, drive it for about 3-5 miles (with no load) and flush, repeat till clean diesel comes out. Fill it with 80w-90 and see if that helps? Remember not to let truck roll forwards when in reverse and vice-versa. Do you hear air when you shift from neutral to either first or reverse? I say the Sprague might not be working right. I had to take the little round dill that is bolted to the TC (4 bolts) and inside that is 2 rubber rings on a brass rod ( the only thing I can compare them too is windmill leathers, I am not sure if that makes any sense? sorry if it don't) Air pushes the brass rod one way for forward and the other way for reverse, I had to smear grease around the (rubber leathers) to get mine to work. hope this helps somewhat?

 

[NovacaineFix]

I would drain the Transfer case and fill it with clean diesel, drive it for about 3-5 miles (with no load) and flush, repeat till clean diesel comes out. Fill it with 80w-90 and see if that helps? Remember not to let truck roll forwards when in reverse and vice-versa. Do you hear air when you shift from neutral to either first or reverse? I say the Sprague might not be working right. I had to take the little round dill that is bolted to the TC (4 bolts) and inside that is 2 rubber rings on a brass rod ( the only thing I can compare them too is windmill leathers, I am not sure if that makes any sense? sorry if it don't) Air pushes the brass rod one way for forward and the other way for reverse, I had to smear grease around the (rubber leathers) to get mine to work. hope this helps somewhat?

I do hear air when shifting from neutral into 1st and more in reverse. I think what I did was let it roll back when it was in 1st. I have a very slight incline on my driveway and when I was backing it in, I most likely rolled one way or the other while in the opposite gear [forward while in reverse and backward while in 1st].

Funny thing is, my '07 Toyota does the almost the same thing, but it is an automatic. I noticed this once while on a incline at a stop sign, it bucks like a person learning to drive a stick.

 

[ClintA]

I learned this on SS, put your truck on level ground (if you can?) with a full tank of air in your M818 jack one front tire off the ground, get in the cab and put your truck in FIRST with ENGINE OFF, get out and turn your front tire that is jacked up forward (It should only go forward, if you can turn it backwards something is wrong), do the same in reverse, it should only turn backwards when in reverse. try that and that will tell us alot

 

[NovacaineFix]

I learned this on SS, put your truck on level ground (if you can?) with a full tank of air in your M818 jack one front tire off the ground, get in the cab and put your truck in FIRST with ENGINE OFF, get out and turn your front tire that is jacked up forward (It should only go forward, if you can turn it backwards something is wrong), do the same in reverse, it should only turn backwards when in reverse. try that and that will tell us alot

That seems to make some sense and fairly easy and straight-forward to do. I have to pick up another jack 1st, since mine is only rated for 2 1/2 tons, but I knew I would need one sooner or later.

This is what I love about good forums, good people helping one another with some issues.
Thank you guys!

 

[JohnnyBM931A2]

That seems to make some sense and fairly easy and straight-forward to do. I have to pick up another jack 1st, since mine is only rated for 2 1/2 tons, but I knew I would need one sooner or later.

This is what I love about good forums, good people helping one another with some issues.
Thank you guys!

For what it's worth, I picked up a 20 ton rated air-over-hydraulic bottle jack from Harbor Freight for $88.00 recently (sale plus 20% off coupon.) That sale has ended, but they are currently at $120 (normally $150.) If you get yourself a 20% off coupon you can get one for $96 before tax. They seem to have very good reviews.