650G Trans slipping in 2nd gear

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CRWFARMS
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650G Trans slipping in 2nd gear

Post by CRWFARMS » Thu Mar 09, 2023 1:45 pm

New here, so be gentle...lol. I've got a 650G Series 4, sn 803789. Was pushing trees out with it yesterday, and 2nd gear starting slipping. Forward and reverse. Other gears are all fine. First thought was clutch pack. Looked at book, 1st and 2nd share a clutch pack.... wouldn't that rule out clutches?? Any thoughts or suggestions?? Thanks

Jim B
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Re: 650G Trans slipping in 2nd gear

Post by Jim B » Thu Mar 09, 2023 4:26 pm

Welcome to the Boards.

LeonardL is much more familiar with the G series than I am and hopefully he will be along soon to help you out, or someone else with more G series background. I have some info on the G series and it looks to me like the first and second speed clutches share a shaft and output gear, however they are two separate clutches, not a shared clutch pack, which have different input gears to make the speed difference. What is the publication number of your "book". I believe the 450G, 550G, and 650G use a two manual set: TM1403 for operation checks and testing and TM1404 for repair. There should be diagnostic and test procedures for the cutches in the TM1403 manual.

Given first and second are not a shared clutch, I would suspect an issue with the second clutch or its valving/oil supply.
Jim

CRWFARMS
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Re: 650G Trans slipping in 2nd gear

Post by CRWFARMS » Thu Mar 09, 2023 6:26 pm

Thanks for the reply. I have both 1403 and 1404 manuals. Guess I'll need to look again at the clutch packs....I thought it showed 1st & 2nd as a shared pack. I do have a gauge ordered to check pressures....but there's no way I can afford a flow meter

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LeonardL
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Re: 650G Trans slipping in 2nd gear

Post by LeonardL » Fri Mar 10, 2023 9:15 am

Hey... welcome to the board. Jim has done a great job of explaining how these G series transmissions work. I would suspect you probably have the same issue with first gear but it hasn't gotten to the point of showing you the slippage yet. First gear is less likely to slip given the ratios being smaller and it is easier for the that range to operate. The higher the gear range the more apt it is to slip.

You should be able to check with a gauge and not need a flow meter. So I would check that first and go from there. I fear you do have a pack getting weak however. I'm not real familiar with the G series transmissions as they just never gave us any trouble. They are for the most part bullet proof. So good luck and keep us posted of what you find with your gauge.
40 plus years working on JD 350s, 400Gs, 450s and other equipment both Ag and Construction.

CRWFARMS
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Re: 650G Trans slipping in 2nd gear

Post by CRWFARMS » Fri Mar 10, 2023 9:46 am

Thank you. Gauges are supposed to be here by next Weds.....will let you know what the readings are. Are aftermarket clutches safe to use...or do I need the high dollar JD parts??

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Lavoy
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Re: 650G Trans slipping in 2nd gear

Post by Lavoy » Fri Mar 10, 2023 2:36 pm

I may have them available, I would need part numbers to check.
Lavoy
Parts and restoration for antique and late model John Deere crawlers.
Owner and moderator www.jdcrawlers.com

CRWFARMS
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Re: 650G Trans slipping in 2nd gear

Post by CRWFARMS » Fri Mar 10, 2023 6:31 pm

Lavoy, looks like disc part # is AT117908. Plates are R80813

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Lavoy
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Re: 650G Trans slipping in 2nd gear

Post by Lavoy » Sat Mar 11, 2023 10:15 am

Looks like $22-$28/each. Waiting on a response from my primary supplier, won't hear back til next week.
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Parts and restoration for antique and late model John Deere crawlers.
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