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wierdscience
12-21-2005, 07:25 PM
I'm in the process of rebuilding my new(to me)forklift torque converter.It's a five piece bolt together case converter.
I got it apart and I don't see any damage outside of wear on some of the thrust faces and the impellar input neck/pump drive.
My question is with all of the pieces stacked together in order there is approximately 1/8" of slack between all the pieces total.I know they have some tolerence between thrust faces,but that seems excessive.Anbody got a clue as to how close those tolerences need to be?I can't find much info on this converter,I can get parts for it,but they are limited to the impellar hub and gaskets.A new converter will be $$$$ and I want to make sure the tranny I have is in working order before I buy a new impellar hub for this one or a whole new converter.

In case it helps this is a Funk bolt together torque converter.

CCWKen
12-21-2005, 08:16 PM
Did you measure between the case thrust faces? Is that where the 1/8" of slack is comming from? (The difference between the stacked assembly and the case?)

The 1/8" (.125) seems a little excessive. I can't help specificlly but most trany clearances are around .040 Max limit. The TC I took out of the old shop truck would "clunk" when inverting. The new one didn't.

wierdscience
12-21-2005, 08:33 PM
1/8" between the stack and the case is it Ken.It has a piece of a fiber washer at one end that is worn.

I was thinking of what it does exactly and it seems so long as the impellar is centered between the drive fin halves it should work fine.

Just was wondering what the minimum tolerences would be to allow for case expansion.Too tight might cause some damage,too loose may not work right at all.

CCWKen
12-21-2005, 08:46 PM
I think .020 would be in the range. .025 at the most.

Dawai
12-21-2005, 11:01 PM
AND, to lap a thrust washer to clearance? You use a piece of glass and a sheet of emery paper...

Or a thousand dollar granite precision piece.

CCWKen
12-21-2005, 11:42 PM
Forgot to mention. The fiber washer is probably to keep it from chattering at low speed or idle. At high speed, there may not be much force on/against it.

Yankee1
12-22-2005, 06:00 PM
Hi,
What about the sprag? What look like rollers in the sprag are actually figure eight shaped in their cross sectional view.
When rotated in one direction they slip and in the other direction they lock the sprag.
Because of their shape they need some endplay to function. The whole sprag may look like its a thrust washer but its a sprag clutch and directional in operation.
Chuck

Yankee1
12-22-2005, 06:12 PM
Hi again,
If its a torque convertor it has a stator.
If its a fluid coupling it does not have a stator.
The torque convertor has a sprag clutch.
The fluid coupling does not have a sprag clutch.
In a torque convertor the fluid is thrown against the driven member which in turn directs it through the stator back against the fluid in the pumping member causing a torque multiplication.
In a fluid coupling without the stator between the driving and driven member there is no torque multiplication.

wierdscience
12-22-2005, 08:10 PM
It is a torque converter because it has a stator,but it doesn't have a sprag.
The tranny has a reduction gear set and two clutch packs,one forward and one reverse along with the usual pump that's it.

Yankee1
12-22-2005, 09:55 PM
Do you think maybe that it could be missing a sprag? They are like a thin thrust washer.
At first look they appear to be a thin thrust washer with small roller bearings.
But what looks like roller bearings are actually figure eight shaped in their sross section view. That would account for the extra space. Look up a view of some other torque convertor assembley and see how they are set up. Good Luck

Yankee1
12-22-2005, 09:56 PM
Do you think maybe that it could be missing a sprag? They are like a thin thrust washer.
At first look they appear to be a thin thrust washer with small roller bearings.
But what looks like roller bearings are actually figure eight shaped in their cross section view. That would account for the extra space. Look up a view of some other torque convertor assembley and see how they are set up. Good Luck

wierdscience
12-22-2005, 10:14 PM
The only thing where the sprag should be is a 1/16" thick fiber washer,that's all.Its possible that it disintigated,I'll keep looking.

It would help If I could find an exploded view of this unit,but that has been made hard since Funk was bought out by John Deere.

Yankee1
12-22-2005, 10:41 PM
It is a common problem that they do come apart under excess heavy load conditions and can't be found. If you do a search for thrust washer type sprag clutch. You will see comments along this line. I think I would call a transmission shop and see what they suggest for replacement types.

Carl
12-23-2005, 09:38 AM
<font face="Verdana, Arial" size="2">Originally posted by wierdscience:
It is a torque converter because it has a stator,but it doesn't have a sprag.
The tranny has a reduction gear set and two clutch packs,one forward and one reverse along with the usual pump that's it.</font>

If it has a stator, it should have a sprag. The sprag locks up to hold the stator stationary when there is a large rotational speed difference between the two rotating members. As the driven member's rotational speed increases to near the rotational speed of the drive member, the sprag unlocks and the converter becomes a fluid coupling. If additional load is added, the sprag once again locks the stator and torque multiplication resumes. That's how an automotive converter works anyway. I suppose a forklift converter may be different, and may have the stator permanently stationary.

CCWKen
12-23-2005, 02:24 PM
I've not seen a stator clutch in the form of a thrust washer. The clutch is usually pressed between the stator and shaft. It's nothing more than a one-way bearing.

But then again, this is a Funk. http://bbs.homeshopmachinist.net//biggrin.gif