Reverse?

[HUS457]

Hey everyone. I kinda talked about this in Ksiesel's thread he started on March of last year. Ended up kinda hijacking the thread so I figured I'd start a new on here.

My seld (15 S-TX) had intermittent reverse failure issues. It would beep, but not engage. The rest of the time it would work. Say 1 out of every 10 times it would fail. So I took the chain case apart and found the shift fork pads failed. So I replaced them & reassembled. (FYI, if anyone else buys these shoes, they're sold individually, not in a pair. For a huge ridiculous markup. $33 CDN ea). I tried it today and it seemed fine but then I thought "I should try it one more time" So I did. Thankfully. I hit the reverse button & immediately heard a loud grinding from the chain case. Better find that in the garage then on the trail. So took it all apart again and it seems like the issue is in the inner splines on the reverse gear. Where it engages the drive gear. Seems the splines built up a very fine lip around the outer edge of the splines possibly preventing it from engaging with the drive gear. When I manually took the reverse gear off, I had to give it a bit of a tug. It was held up a bit. Then when I tried putting it back on I'd have to force it. If I clocked it different some times it would slide on, some times not. I can feel a very fine edge on the splines. When I took it apart last week, it came right off.

Question 1; Has anyone else ran into this? Is it worth taking a file and giving the splines on the reverse gear a fine chamfer? Or is that a lost cause?

But, I'm also thinking "Is this the problem, or is there something else up that caused this?" Last season I put in a Prevost performance top gear bushing at the end of the season. It has a thick collar on it which the original bushing did not. So to make up for the difference I believe there was a washer removed. It all worked fine this year for 1,200klm with the exception of the intermittent reverse failure. There was no grinding noise.

Question 2; How are the 14 & 15's set up on the jack shaft from factory? Right now from the locking collar/nut looking out toward the reverse gear I have 3 thin washers and a larger thicker one. Then the top gear. Then another washer & c clip. Then washer & reverse gear. I'm thinking something may be up there causing the top gear to be shimmed improperly affecting alignment? But there's play there between the top gear & the c clip. .050 maybe?

Don't want to aggravate anyone but we got record snow here and this is no time for the sled to be in the garage waiting on parts. I'm planning actually to trade it on a winder Tuesday. But got to get this together reliably first.

 

[ksiesel]

Due to your comment about hearing grinding when trying to shift into reverse, it makes me think the large plastic gear in your reverse actuator (the black part on the outside of the chain case) is stripping teeth. That will cause you to hear a grinding sound when it attempts to shift. Others have seen this an either replace the gear (you can take this actuator apart) or they clock the gear so that fresh teeth are being engaged rather than the worn ones. Once the actuator is installed in a chaincase, travel is limited so only about 1/3 of the teeth on this gear are used unless it is re-clocked.

 

[74Nitro]

Most of the time this is caused by the top gear bushing failing.
It only takes a few failed shifts to cause the grinding of those little teeth.

 

[HUS457]

Tx guys, I should have mentioned, I replaced the shift actuator before I went into the chaincase. So that’s new as well.

Is replacing the reverse gear common?

 

[74Nitro]

Tx guys, I should have mentioned, I replaced the shift actuator before I went into the chaincase. So that’s new as well.

Is replacing the reverse gear common?

Very common. The bushing is what fails thus creating the potential for the gear to get damaged. How bad is the female gear damaged?

 

[HUS457]

The drive gear seems fine. The splines on the reverse gear that engage with the drive gear have an edge to them that I’m going to try & file down. A friend of mine mentioned; if there’s any play on the splines that engage with the jack shaft it’ll cause failure as well. The only fix for that is to replace the reverse gear. I haven’t checked that play yet, I hope to do so shortly.

 

[74Nitro]

The drive gear seems fine. The splines on the reverse gear that engage with the drive gear have an edge to them that I’m going to try & file down. A friend of mine mentioned; if there’s any play on the splines that engage with the jack shaft it’ll cause failure as well. The only fix for that is to replace the reverse gear. I haven’t checked that play yet, I hope to do so shortly.

The top gear isn't very expensive.

 

[HUS457]

I agree. I believe the top gear was around $120 CDN & the reverse gear was less than that. The problem is, It’ll take a week or more for the part. I’m planning to trade it for a winder Tuesday lol.

 

[HUS457]

I took a 1/2 second video of the reverse gear play on the jack shaft, but for whatever reason it won’t upload. I just keep getting a “Video is too large for the server” message.

But the play on the jack shaft is similar to the top gear play before I replaced the bushing. Looks like this could be an issue.

I’ll keep trying to upload.

 

[74Nitro]

I agree. I believe the top gear was around $120 CDN & the reverse gear was less than that. The problem is, It’ll take a week or more for the part. I’m planning to trade it for a winder Tuesday lol.

I stand corrected. I looked it up, it's over $140 which is twice the price of the Winder top gear.

 

[HUS457]

Got it. The aftermarket top gear bushing I put on at the end of last season has a significant collar on it which the stock one did not. I didn’t have the gear shimmed correctly, to make up for the collar thickness. Which ended up causing the gear to cover the C clip grove. There is a sinister groove immediately outboard of the c clip groove which fooled me. This caused excess play which affected the reverse and top gear engagement / disengagement. Problem corrected.

Further, made it to the dealer this am & I am no longer a Viper owner, I now have a 23 Winder GT. First klm’s in the am!