International b 414 tractor

If you mean the lever itself (2), see attachment, then no, it is held in place with a roll pin (3). So it should not require access inside the case.

They have an internal snap ring

Did you ever figure out what the problem was with your 2615 Massey Ferguson tractor and why it was stuck in gear. I have one that is doing the same thing

If the (High,Low) engagement handle is loose and can move (Low to High) and the tractor stays in low, look for external linkage for missing or loose parts. If the engagement handle is tight and will not come out of low position it sound like there is an internal problem. Look for any external obstructions on the linkage that would keep it from moving. If not the problem could be an internal problem. Possible internal problems could be shifting fork,shifting shaft, or shifting linkage.

You may have a keyway broken in the hi/low selector

http://www.yesterdaystractors.com/atrp/specs/ford.htm
The above link is an excellent site for help. Can you see if the shaft is turning when you try to shift the Sherman Hi/Lo transmission.?
The Sherman units are installed inside the housing between the engine and Ford transmission and I believe you would have to "split" the tractor to access actual Sherman unit. It sounds like either the Hi/lo lever is slipping on the shaft or has broken internally....good luck. Try doing a search for ( Sherman transmission Ford 8n tractor help) there are a lot of Old timer experts out there and this was a very popular addition to the 8n's

linkage is worn. remove deck plate and check shaft going through range cover to see if ts worn.also check arm on verticle shaft to see if keyway is worn. these parts are availeable from your local caseih dealer

well, if you are sitting still it is recommended you put vehicle in neutral and select 4x4 indicator to desired posistion..... 4 high...4 low...or 2high (auto) when you select 4 low the top speed is not to exceed 25 mph. It is a very low gear for crawling or pulling. At any time you need 4 low gear you must stop trk, shift to neutral and select 4 low. The same procedure is done to change from 4 low to 4 hi or 2 hi. if not done this way internal trans, transfer case or driveline failure will occure. At any time you may shift 4x4 selector from (auto) or 2 hi to 4 hi, and 4 hi to 2 hi or( auto).****** But note, do not make shifts while tires are spinning or under power (acceleration)******* While driving you can make shifts at any speed between 2 hi (auto) and 4 hi and back to 2 hi. release throttle a little and select. you do not have to take foot off throttle all the way! just enough that truck is not under a power, load acceleration. If tires are spinning or you are on the gas and you select gears from 2 & 4 high the posibilities of severe damage can result. Also note that 4x4 is not recommended on dry pavement. When 4x4 is being used also take care as to the handling and the steering characteristics change, On tight turns the front wheels will bind and possibly **** a little. If you have never had a 4x4 before, obey what i have told you untill you get the experiance and you will be fine. HAPPY TRAILS.... AND A LITTLE 4X4 FUN!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Hi..my name is Keith..and i restore 9N's,2N's and 8N's....and to replace the ring gear..you split it there at the back of the engine..and its kind of a big job..so i would check the starter 1st..to make sure its not a starter problem..i hope this helps..if not please write back..i love tractor problems