New to me John Deere D105

[FergusonTO35]

So, I got a good deal (well under a grand) on this nice low miles 2017 John Deere D105. She has a 17.5 B&S single cylinder OHV (my favorite riding mower engine), 42" cut, manual blade engagement (which I prefer) and push pedal transaxle with forward/neutral/reverse lever. Mowed with it today and I'm impressed. It's not going to replace my 1990 Murray that's still in service, but will definitely get some use with about 3 acres total I keep mowed.

So, what can you tell me about it? JD says it has an "automatic" transaxle, not hydrostatic. Is it a true automatic with a torque converter? Do these machines have any known trouble areas? The older and bigger members of the family eye it suspiciously from the shed!

 

[066 redeye]

Cam decomp failure.
If it has an early head gasket type, 95% chance it will blow.

 

[EFSM]

JD says it has an "automatic" transaxle, not hydrostatic.

It is a General Transmission unit with a fully plastic housing. We see problems with the axle grease seals pushing out, and issues with the variable pulley mechanism on top of the transmission. Those issues range from pulleys flying apart to the speed adjusters not sliding right due to dirt buildup. To say the least, not a good transmission overall. However, that unit looks well cared for. Keep the transmission clean and don’t pull loads up cliffs. It might treat you pretty well.

 

[GMB74]

This is JD's smallest base-line riding mower. Really meant for small back yards less than an acre. That said it is a rugged little beast and can serve you well if you take care of it and don't beat it to death. When a problem arises, fix it. Don't ignore it and keep going.
All the above comments are accurate.
It has a "variator" style transmission with variable-diameter pullies for infinite gear ratios. Kind of like a torque converter system, but simpler, cheaper.

 

[FergusonTO35]

Huh, so it's kind of like an MTD Varidrive? I always had good luck with those. I have real tractors for pulling and other serious work. I take it this transaxle is filled with grease? Strangely, I have always found the small and simple riding mowers such as my 1990 Murray to have a lot fewer problems than the larger, more complex ones. In fact the Murray has outlasted several would be replacements!

 

[EFSM]

Huh, so it's kind of like an MTD Varidrive? I always had good luck with those. I have real tractors for pulling and other serious work. I take it this transaxle is filled with grease? Strangely, I have always found the small and simple riding mowers such as my 1990 Murray to have a lot fewer problems than the larger, more complex ones. In fact the Murray has outlasted several would be replacements!

Yes, the concept is identical to MTD but many of the components are plastic.

 

[FergusonTO35]

Eee, didn't know that. It looks like JD did a recall on some of these due to transaxle issues, I'll call the dealer with the serial number tomorrow. Mebbe I should buy a spare transaxle or three while I'm at it!

 

[old saw fixer]

You need a Wheel Horse tractor with a 48" deck if you are cutting that much grass...

 

[FergusonTO35]

I should clarify, the new John Deere is only one of several machines that do the mowing. I push mow about an acre for exercise, also have my 1990 Murray riding mower and a 60" finish mower for the tractor. And, an absolutely beat to death and rusty 48" John Deere rider that belongs to dad and just refuses to die.

I downloaded the factory service manual for the transaxle and, as expected, it only covers the external parts. I wonder if it would be worthwhile after the season to put a grease fitting in the case and shoots some grease into it every oil change? Being a variable drive, there should just be a single speed gear set and differential inside the case as with the MTD units. JD shows two part numbers for the transaxle, AUC1107 and AUC15714. AUC1107 costs around $400.00, AUC15714 costs $829.00. AUC1107 has a note of "MY2018" on it, so mebbe that one would fit mine with a 2017 build date. If I can find a complete and non-broken transaxle for cheap I may buy it to experiment with.

 

[EFSM]

I should clarify, the new John Deere is only one of several machines that do the mowing. I push mow about an acre for exercise, also have my 1990 Murray riding mower and a 60" finish mower for the tractor. And, an absolutely beat to death and rusty 48" John Deere rider that belongs to dad and just refuses to die.

I downloaded the factory service manual for the transaxle and, as expected, it only covers the external parts. I wonder if it would be worthwhile after the season to put a grease fitting in the case and shoots some grease into it every oil change? Being a variable drive, there should just be a single speed gear set and differential inside the case as with the MTD units. JD shows two part numbers for the transaxle, AUC1107 and AUC15714. AUC1107 costs around $400.00, AUC15714 costs $829.00. AUC1107 has a note of "MY2018" on it, so mebbe that one would fit mine with a 2017 build date. If I can find a complete and non-broken transaxle for cheap I may buy it to experiment with.

The way it is, they have almost too much grease in them. It can pop the axle seals out.

 

[FergusonTO35]

Huh, that's good to know. Is it possible to replace the axle seals? I wonder if it might help to add a little pin hole vent on top of it? Everything I have read indicates that most problems with these transaxles come from the variable drive system and other external things, and the gearbox on these is fairly dependable as long as it doesn't leak and you don't use it for anything much beyond mowing, as in pulling wagon loads of rock and stuff like that. There is a complete and reasonably low hours looking transaxle on Fleabay for $150.00 with free shipping. I'm thinking about buying it so I'll have it ready to go if needed.

 

[EFSM]

Huh, that's good to know. Is it possible to replace the axle seals? I wonder if it might help to add a little pin hole vent on top of it? Everything I have read indicates that most problems with these transaxles come from the variable drive system and other external things, and the gearbox on these is fairly dependable as long as it doesn't leak and you don't use it for anything much beyond mowing, as in pulling wagon loads of rock and stuff like that. There is a complete and reasonably low hours looking transaxle on Fleabay for $150.00 with free shipping. I'm thinking about buying it so I'll have it ready to go if needed.

Yes, the seals are replaceable, even though GT tells you to just push the seals back in if they come out. I’m not sure if there is a vent in the transmission or not; if not, that would be a thing to add. I’ve never seen internal issues with one of those transmissions.

 

[nbbt]

Maybe a duckbill vent or 2 would keep the preasure down, which could allow for a bit of fresh grease to be added from time to time keeping the stuff semifluid.