Buck 400 Issues

[MassBuck400]

I purchased this Buck 400 last year and having a few issues. Maybe some members have had these and fixed them.

Here are my current issues with the B400.

1. Starting has become a challenge. Not the actual starting of the engine but to keep it running. When I turn the key, it starts up but as soon as I let go of the key and it turns back, the 400 dies. I have learned if I hold the key for a few seconds it will remain running.  Not a clue as to what would cause this or how to fix it?

2. This thing  is very hard to get in gear now. It grinds a lot before it goes in gear. Maybe the clutch needs adjusting?

3. I jerks a lot on take off. This could also be the clutch?

 

Any help would be appreciated. 

 

[kenfain]

Can't really say much about the key issue. Other than maybe a possible ignition switch problem. At least that's where I'd start. If it's easy to pull the ignition from the vehicle, it's extremely easy to test. If not, then it's a bit more trouble to do. And since it might not be the problem, I wouldn't take the dash apart. There are other ways to troubleshoot this. But if you need the details to diagnose a switch. The internet explains it better, and with illustrations too. Just Google it. But if it turns out that's not the problem, then troubleshooting gets more complicated to do long distance. But we'll hammer at it, till it's figured out. 

The shifting issue is probably going to be the real problem. You should definitely try to tighten the adjustment a bit. It'll probably fix it for awhile. Although I have very little confidence that it's the adjustment, that's the best place to start. And it can't hurt. 

Since if it's not an adjustment, at the heart of the problem, then it's probably an internal issue with the clutch itself. However, it sounds like an adjustment might work short term. But it'll start to happen again, till there's no more adjustment left. Or it breaks. Keep us updated on any developments, we'll help where we can. Good luck!

[KentC]

Have you changed the oil in the transmission?  I believe the buck has a wet clutch and shares oil with the transmission.  Changing the transmission oil is a very important part of routine maintenance on the Buck.  

[kenfain]

2 hours ago, KentC said:

Have you changed the oil in the transmission?  I believe the buck has a wet clutch and shares oil with the transmission.  Changing the transmission oil is a very important part of routine maintenance on the Buck.  

KentC is absolutely correct here. Not owning one myself, I tend to forget about the peculiarities of each model. Not only changing oil, but the oil level itself could cause problems. So before you adjust, check the oil level.

[Tobey]

I am also having some issues with my brand new buck. I can not get it to engage front diff to activate 4wd. No fuses seem to be blown.

-Tobey

[kenfain]

6 hours ago, Tobey said:

I am also having some issues with my brand new buck. I can not get it to engage front diff to activate 4wd. No fuses seem to be blown.

-Tobey

Have you checked the fluid?

[Tobey]

Thank you for the suggestion. I had not checked it and when I did I found evidence of water intrusion. I promptly changed the oil in both front and back diffs. Unfortunately the servo inside the front diff appears to be dead. Tried applying 12v directly to connector and it does nothing.  Will have to see if I can get a hold of a service manual  and see how to pull it out.

[KentC]

A super nice guy will send you the service and users manual, if you ask him. Unfortunately I can not recall his user name, but if you do a search in the forums for Buck manual you probably will find him. 

[kenfain]

18 minutes ago, KentC said:

A super nice guy will send you the service and users manual, if you ask him. Unfortunately I can not recall his user name, but if you do a search in the forums for Buck manual you probably will find him. 

Send a PM to Strike250, he's generously provided service manuals to any who ask. As long as it's one of the models that he has the manual for. 

[KentC]

Unfortunately Massimo reminds mr of the Jeep’s made by AMC, where you needed the serial number to figure out what parts were in your vehicle.  Don’t take the manual as a bible, depends a lot on which production model you own. 

[Tom Hoppes]

I must be lucky since I've had zero problems with my Buck 400 in 700+ miles. 
As mentioned above the ignition switch sounds bad.  Mine shifts hard or grinds if the motor is on high idle, I just give it a second or two to slow down then no problem.

[KentC]

I do not believe the Buck has a synchromesh transmission and it is recommended not to shift without stopping. Each time the transmission grinds it is wearing the gears until it eventually fails.   It also leaves metal chips in the oil which causes other problems.  It is important to change the transmission oil in the buck to remove any chips or pollutants, especially since the clutch shares this oil.                        

[KentC]

So. Some times you have no choice but to shift on the fly, but it should be avoided. 

[Mackc]

On 11/22/2020 at 12:36 PM, KentC said:

I do not believe the Buck has a synchromesh transmission and it is recommended not to shift without stopping. Each time the transmission grinds it is wearing the gears until it eventually fails.   It also leaves metal chips in the oil which causes other problems.  It is important to change the transmission oil in the buck to remove any chips or pollutants, especially since the clutch shares this oil.                        

Clutch shares the engine oil.

[Mackc]

On 11/22/2020 at 11:00 AM, Tom Hoppes said:

I must be lucky since I've had zero problems with my Buck 400 in 700+ miles. 
As mentioned above the ignition switch sounds bad.  Mine shifts hard or grinds if the motor is on high idle, I just give it a second or two to slow down then no problem.

After starting in neutral let the engine RPMs drop below 2000 before shifting into gear.

[David martin]

On 10/31/2020 at 12:01 PM, MassBuck400 said:

I purchased this Buck 400 last year and having a few issues. Maybe some members have had these and fixed them.

Here are my current issues with the B400.

1. Starting has become a challenge. Not the actual starting of the engine but to keep it running. When I turn the key, it starts up but as soon as I let go of the key and it turns back, the 400 dies. I have learned if I hold the key for a few seconds it will remain running.  Not a clue as to what would cause this or how to fix it?

2. This thing  is very hard to get in gear now. It grinds a lot before it goes in gear. Maybe the clutch needs adjusting?

3. I jerks a lot on take off. This could also be the clutch?

 

Any help would be appreciated. 

 

My cable finally snapped and Massimo hold no parts. From day one the gears crunched even when I adjusted as they told me to do. They also said not to use P when parked buy N . It still crunched until last week it snapped. No parts. Trying to have it made as it's almost the same as the old Harley throttle cables. Also Boss have it on back order.