Front Axle Trouble

[Rooney7783]

Ok, I haven't had a single problem with mine till this evening. Out of nowhere my front axle seems to have a snag in the gear box. The front axle doesn't engage at the same time as my rear axle. I have completely disassembled the gearbox in search of the problem and found nothing. The gearbox will turn smoothly until all 3 layers are together and won't turn at all with the motor in. I can turn the motor very easily and can turn the gearbox 1 layer at a time or 2 layers at a time, but it freezes with all 3. It doesn't seem to matter what combination I put the layers in either. Even with tons of oil it won't turn properly. Any ideas? I really want to get it running since this was my maiden voyage after installing hobby electronics, cutting and reversing tires, rear axle flip and extension and painting. Before this, it was bone stock, so I'm pretty pissed that it won't work now. Thanks for the help.

[cincinnati]

this is from another post of mine...


i had that exact problem while i was out crawling a creek bed this weekend. my front at first didnt want to catch while going in reverse - then after a while forward didnt want to catch either, so here i was stuck in a creek bed with only 2 wheel drive.

so my first thought was its the gear coming off the motor, because when i picked it up the front tires pulled, just not when there was any load on them. so i stuck it in high and managed to hobble back to camp and get it loaded onto the trailer.

well, i get home and procede to run the rest of the battery out in high up and down my driveway, and notice the front seems to be pulling fine now...... so i flip it over and hold one of the tires and hit the throttle - and it pulls fine now with a load, so......my next assumption is that its the high/low shifter gear by the switch. so i rip it apart and inspect that gear case and discover it is still good, the motor gear is good, and no teeth are stripped or missing, so i put i back together and think theres no reason for it to be stripping/missing and not catching. but its only doing it in low - not high.

so now i think its because the gears are getting out of alignment and not catching on each other like they should. so i try to tighten it all up with some spacers and shims to no avail....... its still slipping.

so i rip it apart for like the 4th time, this time i test the throttle with the cover off and see that its actually the motor itself that is slipping...... so out comes the motor..

so i tear it apart and discover that the motor has a series of gear reduction cases off of the main motor, after like the first 2 cases (its kind of like a dual/triple case setup) there is a drive gear for your high range, then like 2 more reduction cases and the final gear for your low range, well, between the last 2 cases after the high range, there is a gear that is supposed to catch and engage for the low range, its a metal piece that has 3 tabs that are bent at a 45degree angle to cath the plastic gear it is up against, well, after a load is applied that gear has eventually stripped the plastic enough to not allow it to hold.

so how to fix this i bent the metal tabs from like 45degrees to close to 90 so that its not so easy for them to slip out, plus i set a few very small dabs if silicone to each tab to secure it even more.... and after i thought about i realized i could have just put a pretty descent sized drop of silicone right in the center of the gear so it would secure it nicely against the reduction unit. i got it all back together and it works great now . . . on a side not this sporatic slipping happens in the rear axle too but usually when it gets bound up - which is what probably the cause of the reduction case's plastic gear getting stripped. so i am going to perform this tab bend/glue procedure on the rear axle motor to prevent it from doing the same in the future.........

[Rooney7783]

Thanks I'll try that this evening when I get off of work.

[Rooney7783]

Alright, I tried that at it still doesn't work. When I spin the gearbox by hand it will seemingly turn fine then it just hangs up, almost like something is caught in the gears. I guess I'll keep fiddling with it till I figure it out.

[Rooney7783]

Ok, I'm dying here. I've been messing with this thing for hours now and still can't figure out what is causing my problems. Are there any other ideas floating around that might help?

[bugman72]

I had a very similar problem and discovered that the issue was due to two different things. First, take the gearbox assembly apart and take a look at the smaller pinion in the center of the large "high" gear. Mine had a couple of burrs on the teeth and inside the groove. They were causing the binding and subsequent stalling of the axle.

The second thing that caused the problem was overtightening the three bolts that hold the gear reduction assembly together. The first time I put the assembly back together, I noticed that it started catching again, but in a slightly different manner. Once I backed the bolts out a bit and reapplied Locktite, all was well.