Help w/ Front diff question

[MikeK1981]

OK I had taken my truck out for a good bashing and thought everything was all good afterwards. A few days later I went to show somebody how well the brakes worked and I rolled it across the floor. When I hit the brakes it didn't stop well and there was a grinding/clicking noise. I was like 'oh, that's not supposed to happen' LOL. I rolled it on the linoleum floor in the dining room and it looked like the rear wheels were braking normally but the front were still rolling when I braked and the noise was coming from the front diff area. I figured I must have blown the diff, but when I took it apart everything inside the diff looks fine, except one of the bearings by the outdrive was shot. It had actually come apart. If the bearing was locking up or causing friction, would that cause the symptoms with my braking/diff slipping??? I checked out the tranny, the grub screws on the cups to the main drivelines, and tried to turn the cup coming out of the front of the tranny with a screwdriver while applying the brakes and nothing slipped or made that noise. If that bearing wouldn't cause that, what else could? Anybody know which bearings I need for the diff outdrives? Also I need some clutch bell bearings? Can someone help me with part numbers and where I can get them cheap? Thanks in advance.

 

[Combuster]

it could possibly be the bevel gears inside the diff

 

[ScooterB]

The bearing on the ring gear side of the carrier is the diff week link. When replacing your gears make sure you get the gears for the flux as they come with a new revised bearing. The bearing inner race is smaller and will not fit standard gears. This allows larger balls and deeper races for the balls to ride in which results in a bearing with greater side load capabilities.

 

[MikeK1981]

The gears inside the diff look fine. Have you guys ever experienced this with the braking?

ScooterB- You said when I replace the gears to get the ones for the flux. Are you talking about the new bulletproof diff sets? Or are there new spider gears as well for that truck? I have some BP diffs on order through the LHS. With this set, will I need anything else to make these work in the XL? If my spider gears don't look stripped do you guys think the bearing was causing that problem?

 

[ScooterB]

Absolutely! More than once. The bearing can't handle the side loads and blows apart. If not caught quickly the gears are ususlly lost. Ive lost as many fronts as rears probably from hard braking.

 

[ScooterB]

If the gears are ok you can get more use with a new bearing. Check your diff gear play and shim as necessary.

 

[wildchild27]

i had the same thing happen with my truck but i replaced the bearings and all was fine and if the gears look clean then put new bearings in it and let'r rip

 

[ScooterB]

The gears inside the diff look fine. Have you guys ever experienced this with the braking?

ScooterB- You said when I replace the gears to get the ones for the flux. Are you talking about the new bulletproof diff sets? Or are there new spider gears as well for that truck? I have some BP diffs on order through the LHS. With this set, will I need anything else to make these work in the XL? If my spider gears don't look stripped do you guys think the bearing was causing that problem?

Yes. when the bearing goes it will slip. I've had it happen and sometimes the gears are ok and other times they are gone. If ok then replace the bearing and run it til it breaks.

You don't need anything special or extra with the bullet proof diffs.

 

[MikeK1981]

Thanks a ton for the quick help guys! HPISF rules! One more question. I ordered the BP diffs already and looking at the pic it seems that they come with everything I need. However, it only shows one bearing in the pic. So are you supposed to use the new bearing on the gear side and the old sized bearing on the other side? Or does the set come with two bearings even though it only shows one in the pic? Either way, which part number is for the new bearings?

 

[ScooterB]

I bought mine on ebay from a flux. I would not reuse the old bearing.

 

[MikeK1981]

I'm just asking if the newer style bearing goes on one side, and an old-style bearing on the other? Or do you need the new style bearings on both sides? If so why does the set only come with one?

 

[ScooterB]

While on the subject for the benefit of others. If you are running adjustable upper arms you need to check the dogbone play when the suspension is fully compressed. I found that with the suspension conversion setup the dogbones were creating a press and pressing the bearings apart. I found with the flux dogbones I had to remove the o-rings from the cups.
Just a quick FYI.

 

[ScooterB]

The new bearing goes on the ring gear side. Old size on the other.

 

[MikeK1981]

Thank you.

 

[Bankrupter]

MIke Ill be making a thread on how to do both bearings and not just one. Should have it up in a week or so. the BP's only fix half of the issue. I found the fix for the other half...

 

[AllanQ]

I was going to add to check the pinion gear also. In my experience, blown diff bearings = broken pinion also. Since your going to the BP's you will change the pinion out anyway.

 

[MikeK1981]

MIke Ill be making a thread on how to do both bearings and not just one. Should have it up in a week or so. the BP's only fix half of the issue. I found the fix for the other half...

A WEEK?! Now your keeping me in suspense LOL.

Also, I did check the pinion, and completely dismantled the diff cup, spider gears etc. All that stuff looks damage free.

 

[AllanQ]

Good to hear. Bank, I am interested in this fix for the other half.

 

[MikeK1981]

So, just to clarify for myself... Was that chattering noise I was hearing the diff gears (ring and pinion) slipping against each other? Being caused by the bad bearing allowing too much play?

 

[AllanQ]

Yep. that was it.

 

[redneck]

i have had great luck with just machining down the diff cup and ring gear to accept the 8x16x5 (pinion bearing). seems HPI thinks it is a good idea only on the ring gear, but it has worked very well on 3 savages that i have done. Try it, you will save time and money in the lone run!

 

[redneck]

that was posted by ACCESSORIZE, his computer sucks so i let him use my "log-in " to post good info

 

[MikeK1981]

Thanks, I'm getting the BP diffs and I'm going to try the bigger bearing mod on both sides. I'll wait to see what Bank has up his sleeve when he gets the how-to posted for it.