Hi all -- I am trying to help a friend sort out a problem with her '88 TRX300. I don't know much about ATVs so I'll give you as much info as possible, hopefully someone can shed some light on the problem!

When moving forward under power, the rear axle seems to bind, then there's a clunk and it turns, then bind, clunk, turn. We've only tried this at low speeds in 1st or 2nd gear. The problem is worse (louder clunk and stronger bind) with more weight (ie a heavier person or a trailer) that compresses the rear suspension. When it binds, the rear end drops slightly as if the driveshaft is trying to turn the rear axle.

The problem only happens under power moving forwards. It backs up just fine, rolls downhill w/ trans in gear and engine running, and rolls freely with the engine off and the trans in neutral.

I'm not 100% sure where the noise is coming from; the luggage rack was clanking when the bind released, which made it hard to pinpoint.

I tried to check the rear axle oil but the plug is on there pretty tight and I didn't want to strip the plug (need to try again with better tools). I am not sure if the owner has it serviced regularly; usually she takes it in when there's a problem.

The ATV also has a nasty squeal from the rear brakes that's been getting louder over the past year or so, and she hasn't had the brakes checked. (We mostly use the rear brake, since we're constantly setting the parking brake as we move from stall to stall).

The ATV is used on a very small horse farm, two or three times a day and a couple hundred yards per use. It's all slow speeds and lots of idling, usually towing a trailer full of horse feed or horse crap (no idea how heavy - the crap trailer has to weigh 500 lbs loaded, at least - and yes, we use seperate trailers for the feed and the poop [img]i/expressions/face-icon-small-smile.gif[/img]. Recently, a neighbor started using the ATV to haul the full horse crap trailer up a few hundred feet up a steep hill to his garden. Most of the operation is on cement or pavement, so tire scrub has always been a problem - don't know if this could affect axle wear.

Aside from this problem and the brake squeal, it runs and rides nicely and has been relatively trouble-free.

Anyone have any ideas? We are trying to decide if it's worth repairing the RTX or if she should replace it. She's on a fixed income so repair is a better option. If the repair is fairly straightforward, the neighbor and I will do it; her dealer charges an arm and a leg.

Thanks in advance for your help!!

Aaron Gold
autonerd at hotmail dot com

 

There is an axle bearing behind the brake panel that is bad, a common problem in them trx300's

----- Gimpster -----

 

Check the u joints, usually when theres a problem going forward and not back, thats the problem. They could be dry, inside, or really sloppy.

 

Guys - thanks for the help so far. Questions:

1) How bad is it to replace that bearing behind the brake panel? I take it the bearing will clearly be bad when I remove it?

2) Where, exactly, are the universal joints in this thing? Is that where the drive shaft meets the engine/tranny on the frame?

(I told you I know nothing!!!)

Thanks again
Aaron

 

You might want to get a service manual for it. Try the local library, theres a good chance theres one there.
This picture may helpswingarm, or this onerear end.

 

Autonerd,

To confirm the axle bearing is out, jack the rear of the unit up by the hitch. Try lift the right rear wheel up and down. If it moves confirm where. It should show movement where the axle exits the rear brake cover on the right side.

Proceedure is simple for replacement.

Remove --
right wheel and hub
axle jam nut and holding nut
large tin washer and spacer washer
brake panel cover
use a pick and remove the o-ring seal on inner brake drum splines
back off the brake adjuster
take off the brake drum
uninstall the brake cables from the brake pivot arm
remove the vent tube
remove 4 nuts on the back side of the brake panel
slide off the brake panel from the axle
remove old bearing and seal
with a magnet remove bearing ***** that may have fallen into the rearend tube
install the new bearing and seal
check the lower brake shoe for excessive wear, if needed replace shoe set
reinstall in reverse order
since you are back there service the rearend gear assembly

----- Gimpster -----

 

Gimpster: Thanks for the info. If that bearing is bad, would the unit still back up and roll in neutral smoothly?

Hondabuster: Thanks, the owner has a 3rd party service manual (Clymer's, I believe). I know about where that universal joint is, I think.

Again, I really appreciate all the help.

Aaron

 

Im interested in hearing what you find, keep us posted.

 

mine and my friends already had the axle bearings replaced. going straight you won't notice any problems if the bearing isn't totally shot. turning is where you will notice the problem. i didn't replace it myself. however, i can't imagine it would be too much fun.

 

we did replace the bearings on a 400ex and the key is to heat up the carrrier with the old bearing installed in the oven @ 250 degree for 15 minutes or so. while your at it put the new bearings in the freezer. when the 15 minutes is up, the bearings should come out with a little tap. freezing the new bearings shrinks them so they slide in the carrier easier.