Welding manual transmission gears

[iadr]

No I am not talking about what happens when you run a box out of oil, this would be on purpose... lol

I have a situation where the production spline count change on a manual transmission's 5th is preventing me from having the "perfect" ratios that would result from a hybrid geartrain.

I've read (see link @ bottom for one reference to it) that there are some people who regularly weld inner & outers together. Anyone put me in touch with a shop who feels they can do that? I want the inner spline section of one gear cut out and fit into another gear. I think I, or a friend, already have the gears.

Not drag race or road race, but some reasonably aggressive street, so I don't want someone experimenting, who knows nothing of how the machining or welding is correctly done, drastically lowering the torque capacity of the box. This is enough of an "experiment" at best...

Gears are not that heavy, someone suggested sending them to England, that they had heard of a shop there doing this kind of work...?

http://books.google.ca/books?id=TsBde1e ... &q&f=false

[Truckracer]

If it was me I would send both gears to a shop and have one manufactured with the proper outer gears and inner splines.

[iadr]

Well apparently someone's been here before. G-force made a few sets. Really coarse tooth count, and low helical angle= loud.
Hmm, not sure if that's really want I want on the street...

Still thinking...

[MadBill]

Many production trannys rely on press fits for transmitting the torque from shaft to gear and/or vice-versa. A friend had custom gears made for his SC Buick-Fiero and the machine shop just ground the built-in 1st-2nd gear off the input shaft and pressed on the new one. Several of the higher ratios in the box were already press fit from the manufacturer (Getrag in this case) and with almost 400 HP and sticky tires, he had no issues with gear slippage.

As far as I can tell, the force required to press the gear on cold (usually several tons, depending on the interference) about equals the maximum shear force available at the interface. e.g., if the interference fit is say 0.003" and it takes 8 tons (just a guess, but there are charts..) to press the gear onto a 1¼" shaft, the interface could transmit 16,000 lb. at a radius of 0.625", so (16000 x 0.625)/12 = 833 lb-ft.

That said, the shop did weld the snychros into the new gears, rather than relying on just press fit, but I don't think this was necessary.

Don't know where you are in Canada, but the work was done by Jamie Housman in London Ontario: http://www.housemanautosport.com/testimonials.htm

[henny496]

You can machine the outer area off of one gear and bore out the inner on another to press it tightly together. then weld it You want to make one gear out of the two I take it

[BCjohnny]

Press fit alone will get it done, but that little nagging voice never goes away.

A friend who makes modified Mini (A series) gear clusters has the critical parts laser welded, just in case......