418-8 slipping out of hi range

[AHS 1,559]

I know this is a bit scary, but that’s what i had to do to keep it in hi range! This is new to me, and it was in lo range when i got it. I started. Mowing the lawn with it the other day, and the range lever, it felt like it wanted to pull to lo range. Get the strap on there, and it is in hi range. I have a feeling i am gonna have to take it apart to see what is happening in there! Could it be there is a bent hi/lo fork in there?

[squonk 44,582]

Most likely a damaged hi lo fork

 

[Gasaholic 333]

I'd say more likely the detent ball & spring either stuck or spring broke (typically rust)  Better fix it ASAP , or you'll also be needing to replace the shifter fork (if it isnt already bad) as placing that side load on the lever , the fork & gear wear into each other.... But yes it does involve splitting the transmission (and getting those hubs off) 

[stevasaurus 23,453]

I think I have to agree with @Gasaholic on this one.  If it was the shift fork, you would not be able to lift the high gear into place much less hold the shifter in hi gear.  It makes since that it wants to drop into low gear if the detent ball has no spring holding it.  Regardless, it is a tear down to fix it.  

[ri702bill 10,019]

7 hours ago, Gasaholic said:

(and getting those hubs off) 

Strap in, enjoy the ride.... Hubs can be a PITA to remove sometimes. I recently had to pull an 8 speed apart to be able to disassemble the differential, allowing me to pull the axle out to press off the hub.

[AHS 1,559]

So… 45, 41, 42… and 44, 40? I drained low milky fluid out of there. 

[ineedanother 1,728]

I would do a kerosene flush and see if it improves. You might have to split the case and would probably end up doing it anyway.

[Gasaholic 333]

14 hours ago, AHS said:

So… 45, 41, 42… and 44, 40? I drained low milky fluid out of there. 

I'd plan for at  least 40,41,42....   - 45 is unlikely the problem if you are able to shift between high and low easily and it doesnt grind or anything once in either range.. Likewise 44 is unlikely to be the issue (True, it can come unthreaded but that usually leads to simple mis-alignment and once shifted will tend to stay in that position)  what was most common in my experience especially given the milky trans oil, was the detent spring rusted and broke and/or the detent ball jammed in the hole - second most common was abusive shifting that bent the shift fork (40) and third was excessive wear on the shift fork (due to someone side loading the range lever) and it simply wore through and would not shift at all despite the shift lever moving between high and low ranges.   So in any case I would expect to replace at least the fork, spring and ball (We always kept them in stock at the dealership I worked at, if that tells you anything... they weren't FAST-MOVING , but we did enough of them to justify keeping at least 1 fork on hand.) 

[JoeM 8,873]

After flush and cleaning if you still need to bungee strap the lever into high.

Need to fix it because the fork will wear against the sliding gear keeping it over.

If you need to run it consider leaving it in low until you can make the repairs. 

[AHS 1,559]

@Gasaholic good explanation!! So, 44 (the two little indents in it) means the hi and lo setting? It doesn’t grind or anything (if you have the clutch pushed in) 1,2 and 3 work in both hi and lo ranges.

[AHS 1,559]

6 hours ago, JoeM said:

After flush and cleaning if you still need to bungee strap the lever into high.

Need to fix it because the fork will wear against the sliding gear keeping it over.

If you need to run it consider leaving it in low until you can make the repairs. 

Ya, i have mowed a 40 x80 place with it. That’s all. It’s brand new to me. I just want to get it torn apart and fixed. A half a tank thru a 18hp thirsty Kohler!!!

[AHS 1,559]

Is the 8 speed part #; 103916?

[JoeM 8,873]

9 hours ago, AHS said:

Is the 8 speed part #; 103916?

that an early number, late 70's early 80's transmission. Probably work okay but this manual should be a match to your machine.

The last one i worked on had a worn and spread fork. It would only shift into low gear. I had trouble finding a fork and ended up with a good replacement transmission. 

 

[Gasaholic 333]

15 hours ago, AHS said:

@Gasaholic good explanation!! So, 44 (the two little indents in it) means the hi and lo setting? It doesn’t grind or anything (if you have the clutch pushed in) 1,2 and 3 work in both hi and lo ranges.

Yep - #44 is basically a shoulder bolt like as used in the deck gage wheels (but shorter) and machined grooves in the shoulder for the ball detents to keep fork in place if I recall, a 9/16" wrench (or maybe it was 5/8) for the hex, torque was pretty standard (18-20 Ft Lbs if I recall) for 3/8 thread so quite unlikely to ever loosen, you don't need any Loctite or anything on threads , just clean dry threads.  the tricky part is getting the new ball and spring depressed into the "pocket" of the fork while sliding the shoulder bolt through - probably a 1/16" pin punch (with a squared up tip, not rounded over) will do well enough to get the bolt threads started through past the ball far enough that it won't pop out , and then a precision screwdriver (thin blade) to fit between threads and fork body to "squiggle down" the ball to get the shoulder through... 

[AHS 1,559]

#40 im having trouble reaplacing. On parts tree, i can get all the stuff. Guess it time for the rip apart! Thank you!

[ebinmaine 74,509]

1 minute ago, AHS said:

#40 im having trouble reaplacing. On parts tree, i can get all the stuff. Guess it time for the rip apart! Thank you!

 

 

@76c12091520h  or @Jake Kuhn probably has that.