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Advice on making transmission shafts

GregSY

Diamond
Joined
Jan 1, 2005
Location
Houston
I'm in the conceptual phases of a project..where I try to get a handle on how miserable I'd be by the end of it.

I'd need a very small qty of input shafts similar to the one shown made from scratch...there would be some minor differences. Like any transmission shaft, they would need to be made from decently 'strong' material and properly hardened. This shaft is a Chrysler A904-family transmission (3 speed automatic), if that matters.

I've shown the 'small' shaft; I'd also want some bigger versions that have a max diameter of about 1.3 inches.

By small I mean less than 5 of each. As you can see, there are two splined sections and a few shiny ground sections. Plus a couple ring grooves. The rest is lathe turned.

So....my questions:

1) Who is willing and able to make these? I could rough them out but don't have abilities beyond that to spline or grind them.

2) Am I asking for a beating over this...? Is this part so complex that it would cost a mint, etc.?

No, I cannot buy what I want as it's never been made. I also can't modify one of these as that would weaken it beyond use.

Thanks!




A 904 input shaft oa.jpg
 
Is this part so complex that it would cost a mint, etc.?

Depends:D

Rolled spline left end, shaped spine other end - two entirely different ways to make a spline, on two entirely different "sets" of manufacturing equipment

Shiny parts could probably be hard turned

Just the heat treat is not something found in average joe's shop - induction hardened just where needed and just so and so depth
 
Maybe Moonlight will chime in, I think he's done some racecar shaft work.

Otherwise, what about a high end offroad speed shop? Mason Motorsports or Geiser Bros come to mind as they have some pretty trick stub shafts made for their AWD trophy trucks.

Sent from my SM-G973U using Tapatalk
 
I wouldn't care how the splines are made...but the fact they are made two different ways OEM makes me wonder 'why'.

My experience with speed shops are...they don't want to make anything custom for anyone other than themselves. In other words, they might know who to farm this out to, but they won't undertake that on behalf of a third party.

Couldn't the whole shaft be hardened? I'm guessing (?) you'd first turn it and cut the splines, harden it, then finish grind the tight tolerance areas. Or would that not fly?
 
What is the liability if it snaps or the splines strip their teeth? The legal responsibility would make me hesitate. Even if no one is hurt they may try to make you pay for the R&R of the transmission.
On my 2000 Ford Ranger the starter chewed up the ring gear. Just to R&R the trans mission was goijg to be $400 plus $200 or so for a new converter with the ring gear. At 130,000 miles I had them replace the entire transmission as long as they were going to pull it out anyway. The rebuilt transmission has a three year guarantee I think that includes labor at their shop. Not sure about if it ends up somewhere else.
Bill D
 
makes me wonder 'why'.

Right end spline terminates in a relief groove - which incidentally provides a shoulder to act as a "stop" - that end only goes so far into its female spline mate

Such a spline termination could be done on a gear shaper - after the relief groove was there
 
Is this part so complex that it would cost a mint, etc.?

How deep are your pockets for this project? That blind spline is going to be the most expensive feature I would think. Might be a whole lot cheaper to just get a different transmission.
 
Rick Allison is exactly the type of guy I was referring to when I said speed shops are unwilling to tango.

Liability has no role in this discussion. This is a one-off deal that could only result in me suing myself.

Getting a different transmission is not an option...the point is to re-apply the transmission in the manner I want. There is no other transmission that would work any better.
 
Rick Allison is exactly the type of guy I was referring to when I said speed shops are unwilling to tango.

Liability has no role in this discussion. This is a one-off deal that could only result in me suing myself.

Getting a different transmission is not an option...the point is to re-apply the transmission in the manner I want. There is no other transmission that would work any better.

Maybe I am missing something, but google shows a few hits, unless you are just asking about how to do them yourself..?

Custom Splines

Spline shaft manufacturing services - Custom splines shafting supplier


Custom Splines - Power Transmission Components
 
I'm in the conceptual phases of a project..where I try to get a handle on how miserable I'd be by the end of it.

I'd need a very small qty of input shafts similar to the one shown made from scratch...there would be some minor differences. Like any transmission shaft, they would need to be made from decently 'strong' material and properly hardened. This shaft is a Chrysler A904-family transmission (3 speed automatic), if that matters.

I've shown the 'small' shaft; I'd also want some bigger versions that have a max diameter of about 1.3 inches.

By small I mean less than 5 of each. As you can see, there are two splined sections and a few shiny ground sections. Plus a couple ring grooves. The rest is lathe turned.

So....my questions:

1) Who is willing and able to make these? I could rough them out but don't have abilities beyond that to spline or grind them.

2) Am I asking for a beating over this...? Is this part so complex that it would cost a mint, etc.?

No, I cannot buy what I want as it's never been made. I also can't modify one of these as that would weaken it beyond use.

Thanks!




View attachment 264360

It doesn't look like an overly complex shaft. I've done a lot of similar shafts for all types of transmissions and transfer cases.
 
Rick Allison is exactly the type of guy I was referring to when I said speed shops are unwilling to tango.

Liability has no role in this discussion. This is a one-off deal that could only result in me suing myself.

Getting a different transmission is not an option...the point is to re-apply the transmission in the manner I want. There is no other transmission that would work any better.

Did you talk to Rick? I have had very candid conversations with Rick regarding making output shafts and he makes input shafts.

I need a 727 output shaft that at this time is not available.
 
The rolled spline that John refered to above is just the manufacturing method the OEM used because of the much lower cost of rolling (cold forming) the feature versus hobbing it. I my experience, almost all rolled splines are standard involute splines. The blind one on the end is not that big a deal to cut on a gear shaper- certainly not a deal breaker, just a little more of a PITA than if it could be hobbed. You don't mention if this is a super performance application or just your variation of something that you will putt around in or on. Only consideration is for material selection. Are there needle bearings running on those ground surfaces or?? It too makes a difference for material selection.
 
Thanks all.

The bearing surfaces are bushed, not bearing'd.

I've been reading and it seems 300M is a choice steel. Any opinions on that?

I'll call Rick but in the past he seems to have too much going on to mess with anything that's not big volume.
 
In an old job, we'd make splined driveshafts for aircraft generators (we made the parts for the rest of the machine, too). The general process was rough machine, core harden, finish machine, cut splines, carburize & surface harden, finish grind where needed. Some shafts had a copper plating in there someplace as a carburize mask.
 
What I really need is someone who 'does it all the time' and knows how to do it without it becoming a science project. I'm sure there are people like that in China these days....
 
What I really need is someone who 'does it all the time' and knows how to do it without it becoming a science project. I'm sure there are people like that in China these days....

Metalore in El Segundo Ca. can do it. They make their shafts of 300M. They make some beautiful parts that don't break. They "do it all the time"
 








 
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