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Roper Gt18 Lost All Drive

roper sears gt18 transaxle

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#1 telefunkenu47 OFFLINE  

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Posted May 08, 2014 - 07:36 PM

Hello to you all.


Here's the deal.... I've got a Roper / Sears GT18 Twin B&S 6 Speed that's seen roughly 6000hrs of use over its' life. I picked it up from my inlaws after about 2000hrs.

At that time the low range didn't function at all. I was told that it lost low drive gears just after the warranty ran out. I've had no trouble for the past 15 years in high drive but last fall it "jumped" going down grade and I lost all of my high gears as well.


The engine is strong and well maintained. I actually pulled it out this spring and cleaned it up having forgotten about the transaxle issue. Good memory.. just short.


After replacing the spindles, blades, rebuilding the steering gear and fan plate by hand as well as swapping most every pully I'm inclined to take a shot at the transmission.


When running and placed in any high gear it just spins the main pully on the tranny. In first it feels like it wants to pull ahead but I can stop it with my hand.

The pully on the tranny spins freely. I can give it a spin and she'll roll away as though it's connected to nothing at all.

The actual Transaxle is Type:105401X SN:41029

A Sears Model 917.255915 is a dead ringer for my Roper aside from the body metal.


Let me know what you think has happened here. I've pulled the rear end off the tractor already so just need a few ideas to focus on.



Peter Kelly

Tweed, Ontario.

#2 HDWildBill OFFLINE  


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Posted May 08, 2014 - 07:40 PM

Hi Peter, welcome to GTtalk.  The transmission experts should be along shortly.

#3 propane1 OFFLINE  

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Posted May 08, 2014 - 08:10 PM

Hey another Canadian member, welcome. I would say take it apart and see what's in there. Already broke. Can't get any worse, could be a simple fix. Noel.

#4 Gabriel OFFLINE  

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Posted May 08, 2014 - 09:16 PM


#5 KennyP OFFLINE  



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Posted May 09, 2014 - 05:15 AM

:wave: Welcome to the forum! I have one of those trans. out back with 2nd gear out of it. If you were closer, I'd let you have it to fix yours.

Here's a diagram of the innards.

917.255915 drive.jpeg

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#6 boyscout862 OFFLINE  

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Posted May 09, 2014 - 06:03 AM

Welcome to GTT. Check in our Manuals Section for more info. Good Luck, Rick

Edited by boyscout862, May 09, 2014 - 06:04 AM.

#7 KennyP OFFLINE  



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Posted May 09, 2014 - 06:37 AM

Here is the 917.255915 manual. It has the parts breakdown in it also.

#8 MH81 ONLINE  


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Posted May 09, 2014 - 06:57 AM

These would sometimes shear a key at the wheel and just spin the axel. make sure that's not the issue before ripping it open.

With the previous loss of low range, it sounds like damage inside. I would be very surprised if its good news.

Here's hoping tho, let us know what you find.


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Posted May 13, 2014 - 10:50 AM

I think you'll have a hard time determining exactly what the issue is without either X-Ray Vision or splitting the case on the transaxle.

I *think* (I may be wrong) that yours is similar to mine in my SS18. At least they look rather similar in the exploded diagram shown earlier in the thread.

The Hi/Low range selector is the gear set in the "front/left" of this pic:

It takes its input from the shaft just behind and to the right of it in the pic, and its output is the gear pair seen at the top of the stack- the larger gear in the back of the pic connects to the shaft that drives the axle differential. So, if low range was blown out, it's likely either the gears on that same shaft that the brake is on, or the input side of that gearset.

Sometimes what happens in gears like these is that someone "grinds 'em till they finds 'em", which wears down the mating face of the gear (the ones that have the rounded edges that help the gears mesh when they shift into each other) and this can end up making it impossible to get the gears to mesh. I should have got a better pic of my reverse idler gear's mating face, it's starting to get into that condition... but alas, I didn't, and now that trans is reassembled.

The "buck and stop" you describe does sound like some sort of catastrophic failure, and not something like long-term wear caused by being impatient while shifting. Try this: Jack up the back end, get a helper or helpers, put the trans in neutral, spin both tires the same direction and try to inspect the brake pulley. If both tires are spinning forward and the brake pulley isn't turning, your failure is likely in the differential gearset.
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