Requesting Help with Gear Rack Failure on Hydraulic Slide

[LeftOverParts]

Hello MOC members. We just returned from a trip and discovered that the bottom, forward section of our main slide was sticking out more than usual. I thought it might be a in/out slide adjustment issue but discovered that 3 teeth on the forward gear rack have failed or have excessive wear. It appears this condition doesn't allow the spur gear to pull the slide all the way back in.

A few questions:
- Has anyone experienced this and what was the solution?
- Do you think this is covered under Lippert's 3yr frame warranty?
- I talked to one shop and they mentioned the entire tube with the rack has to be changed so 6-7 hrs labor plus parts. Is this reasonable?
- One crazy idea: Since the endmost gear teeth are unused, what do you think about cutting and flipping the front section of the rack and having a mobile welder align and reweld it? See photo.

Your thoughts, comments, and advice will be appreciated.

Thank you in advance!

[Daryles]

I was just reading a discussion regarding gears skipping a few days ago.

Here's a couple of links that were mentioned.
Check the "OuterTube" that the gear tooth/slide ram slides through. Make sure it hasn't bowed up or "crowned" as they (Lippert) call it. Pictures in the links.

Hydraulic slide gear skipping/fix
https://www.montanaowners.com/forums...ad.php?t=87098

The repair for the skipping teeth link…
https://lci-support-doc.s3.amazonaws...cd-0002436.pdf

[mlh]

Can this be done? Sure.
I’ve had a machine shop for over forty years and made several thousand rack and pinion gears. I have a few questions. How are you going to get the right spacing between the gears? They will need to be within .002 and how will you get the piece you put in the right height. Just eyeballing this won’t work. You will need to measure between two gear teeth probably with two pins. You would take two pins probably about a quarter inch in diameter put them in two good teeth and very accurately measure the distance them duplicated that when you weld the new piece in place. You could attach a straight edge on top to get the height right.
So it can be done but at what cost and are you better off in the long run to just fix it once.
Where are you going to find someone with the knowledge and experience to do the job.
Lynwood

[rohrmann]

I replaced a tube with the rack on it several years ago on our rig. Our rig came with the smaller teeth and the 18 tooth gears, but I replaced the damaged tube with the 15 tooth rack and changed the gear from 18 teeth to the 15 tooth gear. Photos of the tube removed with broken teeth, the new tube installed, the slide supported with the tube removed, and another view of the tube removed.

[LeftOverParts]

Thanks for your posts. I really appreciate your input and insights.

Daryles, after reading the links, noticed that most of the teeth on that forward rack have impressions and wear marks - you can sort of see this in the picture comparing the section of the unused teeth to the teeth in the middle of the rack. The teeth on the rearward rack look fine. Seems there is a slide alignment/adjustment issue that caused this.

Mlh, I appreciate your input and experience. I was thinking about a straightedge and potentially buying say, a 1 foot section of spur rack (thinking it's a standard) and clamping that for tooth spacing alignment. I think I could make the dowel or gage pin idea work if needed. This idea was more as a last resort if the repair wasn't covered under warranty, or outrageously costly or complex. I agree that doing it right with a new part is the way to go.

Rohrmann, really appreciate the pictures and details. I was wondering about how to support the slide. I've changed engines, transmissions, and generally work on my cars so the pictures give a good idea about the complexity such that I'd be willing to tackle this job if needed.

Re the warranty, I contacted Lippert customer service and a very courteous and patient rep took my information and opened a case. We spent a lot of time using their service manual and looking at the hydraulic pump to nail down the system. He also provided a link to upload pictures. He thought it would be covered but needed to confirm so I'm to call Tues after the Labor Day on the outcome. He also gave me a list of shops and the trailer shop I contacted happens to be an authorized dealer.

Thanks again. You've been really helpful! This forum is great!

[rohrmann]

The bottle jack extensions are part of my SafeJack kit, along with their adapter for the 12 ton bottle jack. https://safejacks.com/collections/bo...ut-bottle-jack. This kit has been an excellent tool, though not cheap, but much safer than coming up with cribbing. Because I converted the damaged tube to the 15 tooth design, the tube that I purchased had a longer section without teeth at the outer end, so I just cut off the excess and drilled new holes for the bracket that connects to the slide. Also, at the inner end, there is a plastic roller that I transferred to the new tube.