[casual_farmer]

(i initially put this on the cub cadet forum, but it probably makes more sense to move it over here - this is in re to a cub cadet 1170, original transmission mtd part #618-0551, replaced by part #918-0551A):

engine runs, belts are ok, but no go...back wheels won't turn - can't roll it when it's in neutral...jacked up the back end, and could free up the wheels so they would turn in neutral...set it back down, started it up, and it went about three feet before it locked up again...

am guessing this is transaxle which im also guessing isn't good...anything else i should be looking at as a possible cause of this problem?

the part # for this mtd transmission is 618-0551...there's a replacement part #918-0551A...found some information on web that implies these (618-0551)transmissions may be prone to wearing out due to lubrication issues, and that adding a grease fitting or two and pumping in some lube might prolong the service life...this tractor has certainly gone a lot of miles...

anyhoo, seeing the prices for this part new $400 and used on ebay $250 im thinking if the trans is the problem then maybe i can figure out what other models of mtd manufactured tractors use this particular transmission and pick up one for less than the cost of just the part...

anything else i might want to check? i may get brave and crack the thing open just to see if there's any obvious problems...trouble with that is im much better at taking things apart than i am at getting them back together...

and if anyone has a 918-0551A with which they would be willing to part, are reasonably close by (i'm between catskill and oneonta), and isn't trying to fund their kids' entire college educations, let me know...

 

[casual_farmer]

good news is that this particular transmission is common to many mtd models...mtd 600 series also uses it...anyone out there have one they are willing to sell?

 

[casual_farmer]

now im really confused...went out to see if i could get the tractor to roll back to the garage...i moved the shift lever forward to reverse a couple of times and rocked it back and forth - it seemed to roll ok in neutral so just for the heck of it i started it up...i was able to drive it back to the garage no problem...

was thinking i had something broken in the transmission - now im not so sure...parking brake seemed ok...maybe an issue with the pulleys (not sure what this particular set up is called but its a single speed trans - two drive belts and variable size pulley arrangement allows for speed to be increased and decreased by varying pressure on foot pedal...shift lever has three positions - forward neutral and reverse)...

i'm going to leave it in the garage out of the rain for the moment...glad it moves but am wondering what caused it to quit yesterday and if when it will quit again...im open to any and all ideas...

 

[Bob E]

My guess would be to try adjusting the forward/neutral/reverse shift linkage. Directions for doing this are in the MTD operators manuals, don't know about cub cadet... If that doesn't work it could be a worn out shift fork.
My used yard machines with a 618-0163B Transaxle did something similar to what you describe when I first got it, but it hasn't done it since I adjusted the linkage.

 

[casual_farmer]

hi bob - thanks i will see if adjusting the shift linkage helps...it's encouraging that it at least works sometimes - gives me hope that it's something minor...not sure im ready to invest $400 in a new transmission...

one other bit of information i forgot to add...when it locks up, it locks up completely - neither back wheel turns in either direction forward neutral or reverse even when both wheels are off the ground...and when it's locked up, putting it in forward or reverse and pressing the accelerator pedal just burns the belts...when it did lock up the first time, it had been running for a few hours, and i do recall hearing (and feeling) some metallic pops from somewhere under the seat...

most of the lawn is fairly flat but it's pretty large - im guessing this tractor is from '01 or so, and it's got a lot of hours on it...just not ready to give up on it yet cuz it cuts well and starts every time...

 

[Bob E]

Yeah I guess if it's locking up like that it may have chunks of metal floating around inside. I would check the parking break first though.

 

[casual_farmer]

chunks of metal sounds expensive...wish it was the parking brake but no such luck...not sure what to do at this point - thinking either i do have something broken inside the case or maybe the shift lever position was off just enough to make it hang up...would like to see if i can re-create the problem but if it is floating chunks of metal i could end up with more chunks of metal turning the whole mower into one large stationary chunk of metal...too hot to think too much today...supposed to rain tomorrow - good day to be in the garage...

 

[casual_farmer]

looking for mtd transmission 918-0551A

took another look at this thing today...fairly easy to recreate the problem and i think the source is something broken inside the transmission...the linkage is ok, and there are loud popping noises coming from the transmission when moving forward...

it is my understanding that mtd no longer makes parts for the 618-0551 transmission, instead recommending a complete replacement with (the improved) part #918-0551A transmission, which retails for around $400...i don't want to spend that kind of $$$...

so i'm shopping for a used mtd 918-0551A transmission...it is my understanding that mtd has used this transmission on its mtd 600 series lawn tractors, as well as a number of other mtd manufactured brands (troy bilt, cub, etc.)...

if anyone knows where i might be able to pick up this tranny, i would sure appreciate it...

 

[WNYTractorTinkerer]

The pumpkin or differential carrier sounds to have gone kaput..

Try this: If you jack it up and spin one of the rear wheels, does the other spin the opposite direction? If not your spider gears or a carrier bearing is bad. If it does spin, the pinion gear or bearing has a problem.. Chunks of metal is never good in a rear end! Look around and check the local graveyards.. :dunno:

 

[casual_farmer]

it was hot today...so after hauling water to the garden, spraying the beans peas cukes and squash with deer repellant made out of cayenne pepper, and cutting down every burdock on the property and hauling it to the creek, i was sitting in the shady garage drinking iced tea and staring at the little cub...stared for quite a while as a matter of fact...

then after deciding it was too hot to go back outside, i ran the tractor up on the ramp and crawled under it...my first discovery was the part # for the trans is actually 618-0307C...no worries only off by three digits and a letter...

then i rolled it up and down the ramp a couple of times to see if i could get it to lock...it did lock up...but i noticed i could free it up if i picked up the back with the jack...odd i thought...i also heard some squawking from the area of the left axle...after digging down thru some accumulated debris, i saw that the axle was exposed and showed some scoring where it should have been covered by the top part of the transaxle housing...there were also some bits of metal - what was left of the housing - wedged in there - that might have been what was causing the scoring...

after i cleaned that up, i tried it again - altho it worked, it still locked up...but then i noticed if i picked the left rear wheel up off the ground, the axle would drop down to where it should be, and would turn freely again...as soon as the axle popped up, the trans locked and was going nowhere...

so i think (hope) what i have is a break in the housing which, if repaired, would hold the axle in the appropriate position...so now i will refine my search for the appropriate part - i'm thinking the top half of the housing for transaxle part #618-0307C...i'm hoping there is no additional damage internal to the transaxle...maybe i can rig something up to temporarily hold the axle in place to see if it works ok before i go thru the trouble of taking the trans off...

any comments tips suggestions would be greatly appreciated...

 

[casual_farmer]

The pumpkin or differential carrier sounds to have gone kaput..

Try this: If you jack it up and spin one of the rear wheels, does the other spin the opposite direction? If not your spider gears or a carrier bearing is bad. If it does spin, the pinion gear or bearing has a problem.. Chunks of metal is never good in a rear end! Look around and check the local graveyards.. :dunno:

hi WNY,

if jacked up and in Forward or Reverse (and if it isn't locked up) if one wheel is spun the other one goes in the opposite direction...in Neutral each one spins freely and independently...

i think i did figure out what might have been causing it to lock (see my last above)...i can cause it to lock and free it up again - recreated this a few times...i am hoping there isn't anything wrong with the internal workings of the trans, and that the problem is with the break in the upper half of the housing...

 

[casual_farmer]

and the upper housing new is "only" $123...guess that's better than spending $400 on the whole trans or having another paperweight...

 

[VTXRider]

Did something break inside to cause it to wear through the housing? A bad bearing maybe?

 

[casual_farmer]

Did something break inside to cause it to wear through the housing? A bad bearing maybe?

dunno...i hope not...guess i will find out when i pull the thing apart...wish me luck cuz im a lot better at taking things apart than i am at getting them back together...

 

[casual_farmer]

Did something break inside to cause it to wear through the housing? A bad bearing maybe?

found an old thread that describes a similar problem:

MTD 618-0307C Transaxle Noise-Please Help

sounds like this guy had a bearing/sleeve issue on his tractor which caused the top housing to wear out...anyway, i posted a reply to this thread so it should be at or near the top...

 

[casual_farmer]

does anyone know if all of these "Old Part #s" are interchangeable? for example, will a 618-0307D fit a tractor that originally had a 618-0307C? having trouble finding an exact match - but there seems to be a lot of the other "Old Parts" available...

•Transmission
•Genuine MTD Part # 918-0551A
•Supercedes Old Part #'s 918-0551, 918-0307A, 618-0551, 618-0551A 618-0386, 618-0307, 618-0307A, 618-0307B, 618-0307C, 618-0307D

also, MTD made a wide variety of other variants of this particular transaxle...it appears that one of the variations would be in the way in which the wheels are attached to the axle...might be possible to replace my 618-0307C with one of these others if i replace the wheel and the axle as well...which might make sense since the wheels are gonna be a bear to get off anyway...

i looked at trying to replace the bad parts in mine - the upper housing of the trans is pretty much shot so it probably makes more sense to replace the whole thing...

 

[casual_farmer]

i found a replacement transaxle that works so far - have mowed about 3 hours and so far no problems except my top speed is a bit slower than it was....swapping out the transaxle was fairly easy...i also picked up a spare engine and a bunch of other extra parts in the deal...sorry no extra deck tho...the trans wasn't exactly as advertised - pretty big difference in "new from MTD 2 years ago" and "repaired by owner 2 years ago"...but i'm not complaining...i might take the old one apart this winter just to see if i can see what the exact problem was, and maybe it could be fixed who knows...and i might crack the new one open just to make sure it's properly lubed...but that will have to wait until the grass stops growing...

so the good news is the tractor works again and i got it all done for less than half of what the new trans would've cost...and this repair plus all the other fixes ought to get a few more hours out of this tractor...btw it's got 1300 hours on it...

 

[38racing]

Guess i should have stayed watching this thread.had exactly same problem.bought rider sight unseen thinking just needed head gasket. Right axle was through housing and left outer bushing done.had similar unit but brake on wrong side and wheels siezed and wrong size wheels .broke bolts separating bad unit and .turned out bottoms were same .tops were different but replacement would match if i used the drive gear from it too. challenge was finding clay thickened grease . back together waiting to go on mower . my only concern is that cross pin holes in diff house are slightly ovalled so not sure how smooth turning will be.