A 16 spline xtra-long T-Case input gear that drops right in (1 Viewer)

[island45]

Many of you have viewed my thread from a few weeks back about my quest for an 'easy' way to reduce or eliminate the wear on my '78 H42 four speed output shaft. I feel that the title was a bad choice for later searches, and the format was, well 'wordy' to say the least. I had hoped to locate an internally splined coupler or sleeve that matched the 32 mm dia, 16 involute spline so I could fabricate a long gear to bridge across the spline wear, supporting the gear on both sides. There is 5/8" of unused splined shaft beneath the oil seal surface on the trans side, and the tcase opening will accept a gear of 2 3/8" in length. This new gear would have 1 1/4" of balanced drive surface as opposed to the OEM's 7/8". Today I decided to cut my mockup to the 2 3/8" dimension length just so I'd have a model of what I have in mind. This model is made from a discarded u-joint slip yoke and has the required 16 splines, but paralell tooth splines, not involute, and slightly larger outer dia. I would like to see this design (with correct splines and made in one piece) brought to the attention of Taiyo Kiko (Seamaster) Gear or someone that might have interest in producing such a gear. If nothing else, I have talked to a small machine shop that specializes in internally splined couplers of any configuration and I'd use this to turn a shouldered weld-on sleeve to drive my existing gear. I took some photos of this morning's efforts that show an overview of what I came up with.
If one was willing to open up the t-case a bit more as shown in the shaded areas, a gear with an overall length of 3 1/8" could be installed.

 

[charliemeyer007]

I wish you the best of luck. Back in the day I saw a lot of V8's put in with the stock 3 sp T/T and they held up just fine. I might be willing to get lower gears but overdrive is way more important to me these days.

 

[island45]

Funny, much of what I read suggested the old 10 T spline configuration seldom showed much wear, yet we see all modern stuff going to ever finer splines.

 

[Living in the Past]

Finer spline are shallower cut into the shaft leaving a larger core. Agree you do not see the wear. If they fail it's usually a complete break. Under a stock drivetrain including open diffs, stock size tires and linkage that only allows 4WD low not 2WD low you would ever see that failure.

 

[island45]

I feel this gear, if ever produced would be a good choice on a new shaft in a rebuilt transmission. It would increase spline life greatly with contact along it's entire 2 3/8" length and would hold up to some abuse. In a repair role such as mine, the gear would be driven by it's outer ends. During my research I found that long splines in good shape also reduce the oil pumping syndrome as noted in this old thread....
Transfer Case Input Gear Speedi-Sleeve? - https://forum.ih8mud.com/threads/transfer-case-input-gear-speedi-sleeve.529151/

 

[lcwizard]

Finer spline are shallower cut into the shaft leaving a larger core. Agree you do not see the wear. If they fail it's usually a complete break. Under a stock drivetrain including open diffs, stock size tires and linkage that only allows 4WD low not 2WD low you would ever see that failure.

We John, I'm the weird one in that case. My 78, that I bought new, had that gear fail in about 81. I had the trans rebuilt and did a v-8 swap at the same time.
The new gear took crap in about 25K. Back in those days, my youthful exuberance pushed the truck pretty hard. My 40 saw about a 50/50 split pavement to
trails, as many as possible were taxing. That's one reason I haven't used a 40 case in a 40 build since the late 90s. I convert to the 60 split case whenever I can

 

[Living in the Past]

We John, I'm the weird one in that case. My 78, that I bought new, had that gear fail in about 81. I had the trans rebuilt and did a v-8 swap at the same time.
The new gear took crap in about 25K. Back in those days, my youthful exuberance pushed the truck pretty hard. My 40 saw about a 50/50 split pavement to
trails, as many as possible were taxing. That's one reason I haven't used a 40 case in a 40 build since the late 90s. I convert to the 60 split case whenever I can

Dave did you do the V8 conversion before or after you did a end over end down a hill out by P4W?

Did the gear fail or the tailshaft snap off? I've seen some sixteen spline gears that the end of the splines came to a point from slapping back and forth once they started to wear.

I do agree the split transfer case is definitely superior to the one piece. Since I run stock six cylinder F series engine think the 34MM idler are fine for a 40 series. All the split cases I have are off 40 series. Exception will be my 73 that plan to install my remaining complete Fairey Overdrive. Just not sure I want to use three speed transfer case or a nice 78 case I have with the wider gears. Not sure how but ended up with three of 74-4/75 transfer cases with narrow high range gears and wider low range gears that have the same low range as later one piece transfer cases.

 

[lcwizard]

Dave did you do the V8 conversion before or after you did a end over end down a hill out by P4W?

Did the gear fail or the tailshaft snap off? I've seen some sixteen spline gears that the end of the splines came to a point from slapping back and forth once they started to wear.

I do agree the split transfer case is definitely superior to the one piece. Since I run stock six cylinder F series engine think the 34MM idler are fine for a 40 series. All the split cases I have are off 40 series. Exception will be my 73 that plan to install my remaining complete Fairey Overdrive. Just not sure I want to use three speed transfer case or a nice 78 case I have with the wider gears. Not sure how but ended up with three of 74-4/75 transfer cases with narrow high range gears and wider low range gears that have the same low range as later one piece transfer cases.

I did my first v-8 swap in 81. The end over roll was 1998. By that time I was running a TBI350, turbo 400 and a Dana 300 case. The 300 was the only real option for lower land cruiser tcase gears until AA came out with Orion. The 300 was a stock 2.6:1, about 30% lower than the 4speed case. There were 4:1 and 6:1 gears available for it, aftermarket. The splines completely went away on the 4speed about 25K after the rebuild. That was about 1984. At that point I went automatic
with a Dana case which was virtually the same dimensions but cast iron vs. aluminum.

 

[Living in the Past]

I did my first v-8 swap in 81. The end over roll was 1998. By that time I was running a TBI350, turbo 400 and a Dana 300 case. The 300 was the only real option for lower land cruiser tcase gears until AA came out with Orion. The 300 was a stock 2.6:1, about 30% lower than the 4speed case. There were 4:1 and 6:1 gears available for it, aftermarket. The splines completely went away on the 4speed about 25K after the rebuild. That was about 1984. At that point I went automatic
with a Dana case which was virtually the same dimensions but cast iron vs. aluminum.

So the sixteen splines tailshaft never snapped off? Wear I very common on four speed. Never heard of the ten spline wearing, those snap with less mass in the center.

Brain isn't what it use to me. As I remember it was Miles that told me about the end over end.

I never really explored the Orion does not allow the PTO to use and most likely be the same for the Fairey OD? Would have been running one of your Aussie brush guards if the PTO winch would work with one. I have a brain defect that says any 40 series has to be able mount the factory PTO winch.

 

[peesalot]

The Orion will work with a PTO, you can reuse your oem pto gear when installing the Orion unless your tcase had a spacer in whicj case there are plenty of pto gears available.

 

[peesalot]

If you had an extra pto gear you could machine it down to create the piece you want to add to input gear, I am curious about the room to add to that side ? It is a solid stack from input gear against bearing or spacer all the way to where you put the nut on under the cone. Wouldn't you have to modify the spacer or pto gear to get that additional spline on that side of input gear ? If there is space to do it , IMO it's not a bad idea. I would caution to not just weld that additional tube onto gear, thats a tricky process IMO and would require proper weld temp & technique along with machining a shoulder & press fit at the connection to gear like a drive line end onto tube, otherwise, IMO, that weld may crack.

 

[lcwizard]

So the sixteen splines tailshaft never snapped off? Wear I very common on four speed. Never heard of the ten spline wearing, those snap with less mass in the center.

Brain isn't what it use to me. As I remember it was Miles that told me about the end over end.

I never really explored the Orion does not allow the PTO to use and most likely be the same for the Fairey OD? Would have been running one of your Aussie brush guards if the PTO winch would work with one. I have a brain defect that says any 40 series has to be able mount the factory PTO winch.

No it never broke off but the splines stripped out of the input gear and the output shaft splines were down to 1/4 height and thickness

 

[island45]

If you had an extra pto gear you could machine it down to create the piece you want to add to input gear, I am curious about the room to add to that side ? It is a solid stack from input gear against bearing or spacer all the way to where you put the nut on under the cone. Wouldn't you have to modify the spacer or pto gear to get that additional spline on that side of input gear ? If there is space to do it , IMO it's not a bad idea. I would caution to not just weld that additional tube onto gear, thats a tricky process IMO and would require proper weld temp & technique along with machining a shoulder & press fit at the connection to gear like a drive line end onto tube, otherwise, IMO, that weld may crack.

The internal splined shaft expert in West Virginia said he'd produce the splined 16 rooth 32 mm shouldered sleeve and bore out my gear for a press fit in his shop for something like 365.00. Next he'd send it to his certified welder for welding and then he'd carefully and properly heat treat it before shipping it back. Total world be about 500 bucks. Now if the Seamaster guys would just build this in one piece it should just be a bit more material and longer spline . What was once just the area for the oil seal to ride on now has splines under it instead of nothing under it. Isn't that where the transmission oil pumps through? Cost over a factory type gear should be minimal. I would call this a 'straddle' gear as it bridges the narrow wear area that we've all seen on these shafts. Yes, you'd need to shorten the spacer on the back side (and sorry, no pto gear). In closing, even if one could make a long spline gear like the ones for the split case, that works on a cantilever with no outer support for the gear under the worn shaft. That's why the fix of welding the pto gear to the input gear cracks off after time.... Picture it... 5/8" of spline on each side of the worn shaft area as opposed to 7/8" in the center. I have no formal education past high school, but have been a student of geometry, physics and engineering in general for 53 years. The tooling cost may never justify a company selling these, and there's no way I can or would produce this straddle gear, but my gut says it is a viable fix for a fairly common problem on our '74-'79 landcruisers. Seamaster makes them, we drop them in the hole.

 

[island45]

Peesalot, if you study my four photos closely you will note that my rudimentary mockup is indeed a shouldered sleeve with a press fit into my bored out gear.. The overall length of this sleeve is 2 3/8" so it drops through the window. A commercialy produced one piece gear/sleeve unit would of course be superior to welding a splined tube onto a bored out gear. I DO see you have warmed up to the concept and understand what I'm getting at here. Thanks, Gary

 

[cruiseroutfit]

I’ll add my 2 cents, I’ve just not seen the demand over the years. We sell a good number of the 19 spline long gear setups for the split t-case, and a fair number of the (4) different 10 & 16 spline gears we sell. But I can’t think of too many inquires on a long spline 10 or 16 spline input over the decades. It’s definitely happened and I recall having a similar discussion here in a Mud thread… just not enough interest to spool up the machine.

As @peesalot mentioned, if the stock PTO gear would suffice, they are readily available and could be machined/welded to a new input in lieu of a spacer. Might safe some $$.

Regardless, I’m interested in what you come up with.

 

[island45]

A pto gear machined and welded to an input gear still cantilevers the gear, leaving it hovering over the worn area. The gear that straddles the worn area is supported evenly on two sides. Perhaps there is no demand because it doesn't exist, but I know nothing about marketing so I'll leave it be......Funny, with all my ranting about this I'm still too cheap to have one custom made in W Virginia for myself so I reassembeled my T case with a new input gear that I had bought from cruiseroutfitters and it now has half the play it had in that area. My thought was the frankentruck I built on my FJ55 chassis doesn't even have a cab or doors and I live in Western Washington. Heck, I can only drive it in nice weather (two months) and I'm 71 yrs old. I bet it gets 500 miles a year. The rest of the case I rebuilt with new shafts and gears where needed, bearings, seals etc from C.O. Ithink it will hold up fine. I plan to install it next month but a part of me still says to just put that split case and 4 speed from that rolled over '84 that I bought in the late 90s. Maybe that's why the demand is low. A lot of folks just find later running gear. I wonder if one of those honda accord rotors my kid tossed in the shop trash can could be mounted on the driveline,,,,

 

[cruiseroutfit]

Funny, with all my ranting about this I'm still too cheap to have one custom made in W Virginia for myself so I reassembeled my T case with a new input gear that I had bought from cruiseroutfitters and it now has half the play it had in that area. My thought was the frankentruck I built on my FJ55 chassis doesn't even have a cab or doors and I live in Western Washington. Heck, I can only drive it in nice weather (two months) and I'm 71 yrs old. I bet it gets 500 miles a year. The rest of the case I rebuilt with new shafts and gears where needed, bearings, seals etc from C.O. Ithink it will hold up fine.

Right on, thank you!!!

I plan to install it next month but a part of me still says to just put that split case and 4 speed from that rolled over '84 that I bought in the late 90s. Maybe that's why the demand is low. A lot of folks just find later running gear. I wonder if one of those honda accord rotors my kid tossed in the shop trash can could be mounted on the driveline,,,,

I think you are spot on. Demand for 1pc cases in general is down as more and more convert to the split case. The BF1 split cases are not perfect but they are pretty damn solid and can be regeared in high and low range which is nice. I’ve got a split case in my 40… zero regrets. But I’d have no hesitation running a 1pc case in a Cruiser either.

 

[lcwizard]

The internal splined shaft expert in West Virginia said he'd produce the splined 16 rooth 32 mm shouldered sleeve and bore out my gear for a press fit in his shop for something like 365.00. Next he'd send it to his certified welder for welding and then he'd carefully and properly heat treat it before shipping it back. Total world be about 500 bucks. Now if the Seamaster guys would just build this in one piece it should just be a bit more material and longer spline . What was once just the area for the oil seal to ride on now has splines under it instead of nothing under it. Isn't that where the transmission oil pumps through? Cost over a factory type gear should be minimal. I would call this a 'straddle' gear as it bridges the narrow wear area that we've all seen on these shafts. Yes, you'd need to shorten the spacer on the back side (and sorry, no pto gear). In closing, even if one could make a long spline gear like the ones for the split case, that works on a cantilever with no outer support for the gear under the worn shaft. That's why the fix of welding the pto gear to the input gear cracks off after time.... Picture it... 5/8" of spline on each side of the worn shaft area as opposed to 7/8" in the center. I have no formal education past high school, but have been a student of geometry, physics and engineering in general for 53 years. The tooling cost may never justify a company selling these, and there's no way I can or would produce this straddle gear, but my gut says it is a viable fix for a fairly common problem on our '74-'79 landcruisers. Seamaster makes them, we drop them in the hole.

This was done back in the 80s. The PTO was eliminated and the space was taken by an extension of splines off the back of the input gear.
I can't recall the manufacturer but I thought it may have been Australian. Mark's of AU did their input for the low range 60 split case gears in
a similar fashion, with extended splines in the first generation of gears.. May have been McNamara of AU that built the gear for the 40

 

[lcwizard]

It appears that McNamara, may still do this

Jack McNamara - Differential Specialists

 

[island45]

I'm seeing Mcnamara's as being for the 5 speed with a note to contract them about a similar gear for a 4 speed. I just may do that to see what they have up their sleeve. This only because it interests me. The armchair (ok, hillbilly) engineer in me still says that adding even 2" of spline behind the input gear does not add as much strength and support as filling that 5/8" void below the machined oil seal surface with 5/8" worth of splines. Talk about beating a dead horse..... SO, Let's say I pull the trigger on installing my split case. I have searched the parking brake issue quite exhaustively over the years and I'm not going to source expensive factory unicorn parts. I will deal with that in my own manner. But, will the split case/4 speed from the '84 60 bolt in and work with my existing FJ55 drive shafts? I adapted honda rotors with willwood mechanical calipers to my '85 Case skidsteer many years ago and this setup holds the 6000 lb hydrostatic machine anywhere I park it on my mountainside property which is steeper than the proverbial 'cow's face'. Parking brake work, if I go this route would be covered in a seperate thread. So split case works with existing drivelines? Thanks