Ford 750 rebuild, weak tranny questions

[obleck]

Hi all,

I have a Ford 750 TLB that I've been resurrecting, and right now I have the motor out for a sleeve job (it's got a cylinder wall cavitation pinhole).

My question is this: what if anything should I do to the torque converter and/or tranny while the engine is out?

It's hard to say since I don't have anything to gauge it against, but it seemed like I wasn't get much power to the wheels, certainly not as much as the engine seemed to be making. 1st and 2nd gear work, and 3rd is almost useless except on flat pavement or downhill. Uphill in 1st, on say a 20-25% grade, with the engine rev'd pretty high it moves but it's very slow. It digs alright though.

I'm not very familiar with automatic transmissions per se, but what if anything could be going on? Is the torque converter not transmitting power to the tranny? My understanding is that the transmission shifts by having various hydraulically actuated clutches "grab" the appropriate gear, and since the thing shifts okay, is that all it needs to do, or do these clutches somehow slip too? There is a dump valve, which again I don't know much about, but could that be something to look at?

I've filled the hydraulic oil reservoir and changed the filter.

Comments?

Thanks!

 

[rust farmer]

Obleck,
If you have the engine out of the machine it wouldn't hurt to take a look at the torque converter and the forward/reverse clutch packs to see if they need replaced. I don't know anything about your machine, but I own a Ford 5500. My machine moved around, but the clutch discs were worn down pretty bad and the torque converter was trashed. If you don't have a repair manual, spend the money and get one, you'll need it if you plan to do your own repairs.
Good luck with your project.

 

[El Hombre]

Obleck,
If you have the engine out of the machine it wouldn't hurt to take a look at the torque converter and the forward/reverse clutch packs to see if they need replaced. I don't know anything about your machine, but I own a Ford 5500. My machine moved around, but the clutch discs were worn down pretty bad and the torque converter was trashed. If you don't have a repair manual, spend the money and get one, you'll need it if you plan to do your own repairs.
Good luck with your project.

I've got a 5550; which is a slightly newer model. The 750 is what replaced our beasts in '74. Really only difference was a turbo and a 50% bigger hydraulic pump to move enough oil to get those big 6"+ diameter cylinders really moving. The torque convertor is about the only weak point from what I've read, the local Ford dealer tells me, and talking to another guy with a 5500 that had to replace the convertor. He spent $1500 to buy all the parts out of England to rebuild the convertor. This was about 20 years ago, so pre internet. So it wasn't easy to track down US sources of parts and rebuilding labor.

OP,
The transmission doesn't work like a car automatic. You're doing the shifting when you move the hi-lo and the 1-2-3. Only the forward-reverse shuttle has friction plates and apply pistons and oil under pressure. That would be a good place to look while it's split, those are the only parts that would be called an auto.

I would start looking around for somebody that can service and repair an English convertor in this country. There has to be some other industrial applications for that convertor, and hopefully somebody you can find.

But truthfully, anything in high range is just for moving it on flat roads. I use first and second 90% of the time and third if I'm trying to make some time driving around my acreage. I have a paved driveway that's about 20% and it's wide open throttle in first to get it up the hill. Second just heats up the oil as the convertor is slipping like crazy cause it can't get up the hill. Are you sure you had it in low? and not high? Huge difference in those, high is like an overdrive and worthless for any kind of work.

Get a manual, there's a whole lot of a hoe that is new and strange, even if you were already a car wrench like I was. Best money you can spend.