FG Monster truck rev's but has little torque/forward drive.

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VAMPIRE V12

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Hi.
I wonder if anyone can point me in the right direction?
My young sons FG Monster truck will rev freely but, it will not drive forward with much torque or drive.
It seems as though the clutch is slipping???
All the drive cogs are on their respective shafts tight and are not spinning or slipping.
How can I check if his clutch is gone?

I have recently replaced his lay shaft for the upgraded light race shaft and replaced the gear carrier for an aluminium one, along with the 48 tooth gear.
All these bits and bobs are on nice and tight and the grub screws have thread lock on them.
The differential has just been serviced and repacked with good high temp grease.
The clutch bell has been cleaned out with auto brake cleaner, as has the clutch.
The brake solvent is one where it does not leave any deposits behind and there is no grease or oil where it shouldn't be.

I'm stumpped and at a loss???

Any help is much appreciated.

Cheers.
 
Have you picked up the rearend and tired that to see if the pinion is spinning? Check to see if that is spinning. then follow all moving parts to the wheels (check to make sure the wheels haven't stripped out this happened to me) If you think it is the clutch then you will have to pull the engine.
 
Have you checked to see if the rear brake is binding? It happened on my fgbaja.
Was it running OK before you put the carrier and layshaft in?
Do what neverhappy said and work through everything.....clutches don't usually just go bad all of a sudden unless the spring snaps then it'll engage too early at low revs and will have a hard time accelerating and bog down. They can get too hot and glaze or throw a pad off the shoe plate as well.
 
Have you checked the drive shafts are not broken or a pin has snapped off? As mentioned before you need to trace from the wheels back until you locate the problem. :)
 
Hi guys.
Many thanks for the suggestions.
I'll try and have a good look at all the drive train etc.
As I say, the truck does move forward, but with little/no torque behind it.
Cheers.
 
neverhappy said:
Have you picked up the rearend and tired that to see if the pinion is spinning? Check to see if that is spinning. then follow all moving parts to the wheels (check to make sure the wheels haven't stripped out this happened to me) If you think it is the clutch then you will have to pull the engine.
Click to expand...

Hi neverhappy.
Can you please explain what you mean by "the pinion"?
Where is that please and can you describe it?
Cheers.
 
pinion gear is the one connected to the clutch bell. Right off the engine switch turns the spur gear on the layshaft, the the layshaft turns the final drive gear switch turns the diff gear on the diff housing. Your brakes are also on the layshaft check to see if they are stuck closed.
 
Your grub screws on the wheel squares may be loose enough to slip under wide open throttle (WOT). Check to make sure they are tight. It only takes one side to screw the whole thing.
 
Hi guys.

Sorry for not posting up sooner.
My shift pattern has been bad so have had little time to work on the sons FG problem.
Anyhow, with all your excellent advise, I traced the problem to one of the back wheels.
Inside the wheel where it meets the wheel squares, the insides of the plastic wheel which should be all nice and square are all rounded out.
Does this mean I have to buy a new set of wheels, or are these internal wheel squares inserts that can be replaced?
All the drive was being put to the spinning rear wheel due to it being an open diff. The other rear wheel squares are OK.
He has his truck running well now as I flipped the fronts to the back and he now has drive to the rears.
Cheers for all the help.
Al.
 
I would assume the rear wheel nut loosened and backed out enough for the square to spin. I had the same issue with mine and ended up putting it in the front like you. When you tighten the locking nut make sure to use a new nut or coat the end of the nut and shaft with some ZAP II adhesive thats what I do and have not had any of my screws some loose. (Except for the ones in my head.):clown: You can get it at hobby shops and on ebay. Cheap glue and I use it for everything, including body repairs to my 1/5ths and CX2 Blade heli.

CLICK HERE FOR ZAP INFO

ZAP II ON EBAY
 
I'm glad you found the problem. This is the same thing that happened to me. Also put the wheel on the front- But I had to cut the metal band off cause the mounting nut melted into the wheel.

I'm going with the elcon parts too for backup wheels because I go between Stadium and MT setup.
 
You can fix this issue. Take the wheel and a square hub off. Grease the square hub and then place it into the wheel directly in the middle. Make sure you put it in exactly where it needs to be. You should still be able to see where it goes. Mix yourself some 5 minute epoxy and poor it in around the insides using a toothpick. Give it about 5-8 minutes to begin to harden and then remove the square hub. It will be a bit tight, but will come out. Now let the glue settle in. It should already be hard enough where it is a solid, but will still need 24 hours to cure completely. I have done this before for my friend and it works out very well. He still used them. :)

Do note that if you pull the square hub out early the glue will mess up. Also note that keeping the hub in there for much longer than 5-8 minutes may or may not be ok. I don't know since I never kept it in there for longer than it needed to be. I was able to tell how hard the glue was based on the left over glue where I was mixing it.

-Alex-
 
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