Author Topic: New first gear in Coot  (Read 107 times)

Offline Allwheeldrive

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Re: New first gear in Coot
« Reply #9 on: September 18, 2017, 10:33:47 AM »


More videos to come, 2 days of extreme off road.

Offline Allwheeldrive

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Re: New first gear in Coot
« Reply #8 on: September 14, 2017, 08:35:47 AM »
Hey Mike, thanks for posting all those pics .what is the top speed on the Coot?
Looks like you could change the gear ratio if needed.
Maybe change them all to helical gears.

Top speed is (est) 15-20mph in 2nd and 1.5mph in 1st.
Final drive ratio:
1st is 166:1
2nd is (haven't counted teeth) something like 17:1 

I recently installed a 12 tooth sprocket (original 15) to offset larger tires and giving a little more toque (14% gear reduction net)
This doesn't have much effect on 1st gear top speed  1.75 to 1.5mph doesn't feel any different. but it makes 2nd gear a lot more responsive and less likely to slip on the clutch. 1st gear is now approximately 189:1 which makes engine breaking a bit more tedious. The throttle must always be down if you want to move forward otherwise the engine breaking is like hitting a brick wall and will lock up all 4 tires even on incredibly sketchy downgrades.   

In a dream world where I had unlimited funds I'd love to ship the entire transmission out to you and just have you replace all the gears.

I'd get 1st gear higher so that the tiny pinon gear could be much more beefy and simply offset the ratio with different size chain sprockets. There really is plenty of room for final ratio change there and it was silly to try and make such a low crawler gear in the transmission by sacrificing durability. Likewise I'd get 2nd gear to be lower as well to off set the final drive reduction in gearing. But that is in a dream world maybe in a few years with a new job lol.   

I had the Coot out yesterday and was putting it through its paces, good fun. Will have friends down this weekend so videos will likely fallow.

Offline George

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Re: New first gear in Coot
« Reply #7 on: September 13, 2017, 10:12:32 PM »
Nice!

Get some video up of the tranny in action!

Online WFO

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Re: New first gear in Coot
« Reply #6 on: September 13, 2017, 08:52:22 PM »
yea what he said.
"94" MAX IV SPRINGER & ULTIMATE BEARINGS
BE JUDGED BY YOUR CHARACTER

Offline whipperag

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Re: New first gear in Coot
« Reply #5 on: September 13, 2017, 07:49:07 PM »
Got my new 1st gears from WhipperAG / Apache Gear Inc. for the Coot. Super high quality.

Pictured new vs old and installed. You can see how I have changed the design to be much more beefy. I took the risk of increasing the wall thickness of the collars (Plus adding a 2nd). I measured with shims how much room I had to work with and split the difference for a few thousands of clearance. Everything seemed to run smoothly but once I installed the roll pin the gear lost what clearance it had and meshed with the big 1st gear when in 2nd as can be seen in the zoomed in photo. I sanded some material away but it seems like itís more a function of slop in the entire transmission thatís doing it more than anything as the same teeth and spot never rubs twice. The gears still spin easily by hand so I reassembled it and put the Coot back together. Granted in 2nd I get an audible chatter as 1st walks or clips the collar of 1st pinion (the replaced gear) when in 2nd from the lack of clearance. Everything runs nice and shifts smoothly regardless. Itís annoying to image that inside the transmission 2 gears are clashing and making a racket but Iíll leave them be and just wait for one to wear the other until they miss or get quieter as I figure I can either remove material until they stop clashing or just wait till they do it on their own. I have placed a ton of very powerful Neodymium magnets on the bottom of the transmission to help yank any steel shavings from the clashing gears down. I have driven the Coot maybe 1 hour so far and the sound in 2nd hasn't gotten any quieter but it also hasn't broken either which is good.

You talked about everything was fine until you put the roll pin in. Is it not flush and sticking up?
When you talk about the slop in the whole transmission, what exactly do you mean?
That could be a few different things. Are any of the shafts bent? What about the bearings, did you put new bearings in it? And from what I can see most of the other gears look to be in pretty bad shape. They look pitted and worn and probably have to much backlash. All of those things contribute to a noisy gear box.
You might want to try some heavy gear oil like 140 weight. I would definitely get some new bearings.That's what holds things in place. Just new bearings alone may quiet it down.
Waiting for the gears to wear in may not be a good idea, the old worn pitted gears are only going to get worse. The metal shavings you're trying to catch with the magnets will get into the bearings (they may already have) and get ground in the gear teeth causing even more pitting. What kind of bearings are in it?
Needle, tapered, roller bearings.
I would definitely do some more inspection on the gear box.


















« Last Edit: September 13, 2017, 10:32:54 PM by whipperag »
Whipperag

Offline whipperag

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Re: New first gear in Coot
« Reply #4 on: September 13, 2017, 06:43:09 PM »
Hey Mike, thanks for posting all those pics .what is the top speed on the Coot?
Looks like you could change the gear ratio if needed.
Maybe change them all to helical gears.
Whipperag

Offline ascaw

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Re: New first gear in Coot
« Reply #3 on: September 13, 2017, 04:47:05 PM »
That is some Very impressive work rite there !!!

 iagree

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Re: New first gear in Coot
« Reply #2 on: September 13, 2017, 04:44:09 PM »
That is some Very impressive work rite there !!!

Offline Allwheeldrive

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New first gear in Coot
« Reply #1 on: September 13, 2017, 10:40:03 AM »
Got my new 1st gears from WhipperAG / Apache Gear Inc. for the Coot. Super high quality.

Pictured new vs old and installed. You can see how I have changed the design to be much more beefy. I took the risk of increasing the wall thickness of the collars (Plus adding a 2nd). I measured with shims how much room I had to work with and split the difference for a few thousands of clearance. Everything seemed to run smoothly but once I installed the roll pin the gear lost what clearance it had and meshed with the big 1st gear when in 2nd as can be seen in the zoomed in photo. I sanded some material away but it seems like itís more a function of slop in the entire transmission thatís doing it more than anything as the same teeth and spot never rubs twice. The gears still spin easily by hand so I reassembled it and put the Coot back together. Granted in 2nd I get an audible chatter as 1st walks or clips the collar of 1st pinion (the replaced gear) when in 2nd from the lack of clearance. Everything runs nice and shifts smoothly regardless. Itís annoying to image that inside the transmission 2 gears are clashing and making a racket but Iíll leave them be and just wait for one to wear the other until they miss or get quieter as I figure I can either remove material until they stop clashing or just wait till they do it on their own. I have placed a ton of very powerful Neodymium magnets on the bottom of the transmission to help yank any steel shavings from the clashing gears down. I have driven the Coot maybe 1 hour so far and the sound in 2nd hasn't gotten any quieter but it also hasn't broken either which is good.