vortec_7

iTrader: (2)

Has anyone here ever put the synchro hubs and gears back on a T-56 without using a press?

I know it's common industry practice to heat up a gear with a hole in it and slide it down over a room temperature rod, then as the gear cools, it contracts and fits to the rod much like we need to do with our T-56's. I have a stove in my garage that I could heat up a pot of tranny fluid with which to soak gears in too...mwahaha.

The synchro hubs are all aluminum, so they would have greater expansion rates for a given temperature. I'm going to get a micrometer and do the calculations on how hot I need to get the gears so they'll fit. I think this just may work.

Somehow I have a feeling this has been done before...anyone?

ROCNDAV

iTrader: (100)

It could be done. I put the 5/6 assembly back together last night without using the press (except for the bearings #104 & 106).

I suppose you could get a piece of 2" pipe and tap on it a bit to ease it down the splines.

thesource

iTrader: (60)

I don't know what year T56 you are working on but I have never seen aluminum hubs in them before ?????
As far as presses go , you can use drivers to put them back on the mainshaft as well as large flat bladed chisels if you know what you are doing . The 5-6 gears go on pretty easy if used , they are super tight when using a new mainshaft and gears like we do on the Hp series units .

Good luck on your adventure ..............

vortec_7

iTrader: (2)

I just touched one of the case magnets to the synchro and they seem to be ferrous. I thought the synchros were aluminum because they were a little lighter in color than most of the other steel inside the transmission. It always blew my mind as to why they would do that though...

So noone has considered heating the hubs up, but they have been put back on with pipe and chisels? Sounds like if I heated them it would even be easier because the hole in the midlle will grow a small amount as the shaft stays the same. I might try cooling the shaft as well. If I get them hot enough they might even slide right on without needing to be tapped...

My new second gear is in the mail right now so I'll find out soon enough I guess.

wrencher

iTrader: (2)

I dont know if I like the idea of heat & the mainshaft. The plastic caged needle bearings for the speed gears might not be very forgiving.

vortec_7

iTrader: (2)

No, you wouldn't want to heat the mainshaft, just the synchro hub. That way the entire piece expands a small amount while the shaft stays the same, or if I cool it, shrinks. I would use some sort of oil, most likely tranny fluid to heat the hub in in order to get a uniform temperature throughout, and wait before assembling any heat sensitive parts like any plastics until the hub has cooled. They use this process in industry to fix gears to shafts all the time...I believe it is called a heat fit, but I'm not sure.

I'm going to take some measurements with a micrometer and do some calculations to see just how much expansion I should expect for a given temperature. This will also tell me ~ how high I have to heat things.

calhoon

iTrader: (6)

Heat to the gears is a classic newbe FXXXX UP . How much control you have with heat is key. The gears are tempered at 350 degrees F so you can easily destroy th e heat treat if you heat them too log OR too high. I see no real advantage to this step and some obvious pit falls.

vortec_7

iTrader: (2)

Hmm...350F is pretty low. I do know someone with a press but I really didnt want to bother the guy cause hes so busy all the time...but screwing up the heat treat would be worse.

edit: are you talking about the gears or the synchro hubs being treated like this?

wrencher

iTrader: (2)

I know what your saying, but my point is you dont have a choice. You has to be certain plastic parts in place & those hubs butt right up to them. So IMO it would not be a good idea.

Bugsquawsher

iTrader: (1)

Yea don't use heat on anything in there.
The Gears Don't need the Pressing
They all ride on Bearings
Its the Synchro Assmeblies that fit on splines on the main shaft.
I would'nt beat on them either. I'm sure someone out there has done it with out a problem. But they Got lucky.
I have done Alot Of T56 rebuilds and have seen some that Almost fall apart.
Other Were damn near impossible to get apart.
You know you are in trouble if the 5-6 Driven gear won't just slide off.
You need a Special Tool to get them off. I made one at work.
If you replace any bearings, you will need to reshim the Whole tranny innerds.
These things are not hard to rebuild if you have the right tools and are a decent Mechanic.
But they are also Easy to **** up in a hurry if you dont' know all the little tricks.

ROCNDAV

iTrader: (100)

yeah, they're not so tight that heat is required. I could pull all of mine apart by hand. I pressed the 1/2 & 3/4 syncros on with the press (and a 2" water pipe) but probably could have done so with a 24" piece of 2" abs pipe & hammer/seal driver.

vortec_7

iTrader: (2)

Last night I reassembled my 1-2 assembly using nothing more than my old busted 2nd gear and my hands kind of like you would use a slide hammer.

I plan on putting everything else back together like this as well...I'll let everyone know how it goes. I don't anticipate any problems. No press necessary.