Hydrogear Removal From Transaxle NoGo

[Ran d 24]

Started disassembly of a hydro gear transaxle today. As per normal, one hub came off easily with wollered out keyway in the shaft and hub. The other hub was rusted in place. For three or four days, I sprayed PB blaster into the threaded hole for the key jamb screw and around the axle where you see it almost flush with the hub. I tried several different hammers to pound the hub off. No luck. Tried a 3 jaw puller. No luck. Today, I went back to the hammer method. The axle came out of the transaxle. I can see the snap ring when I look inside the axle bore. It does not look broken. So I decided to procede with removal of the hydrogear assy from the transaxle after draining ATF from the transaxle. I removed three hex head bolts and two long thru bolt and nuts. I have been referencing the "Automatic Transmission Repair Manual page 52, fig. 94. I am now not sure what to think because with ALL of the bolts (5) out of the hydrogear, I can't get it to move at all. The manual states: "Slide the hydrogear rearward to disengage the cam block pin from the cam block and lift the assembly off the transaxle". At first, I thought the assy may have a dowel pin or two for precise location. Not the case. The hydrogear will not budge. Could it be due to sealant? I can't see a gasket at the parting line. This transaxle did work when removed. The pump i.d. plate is marked model #90-2046 and serial #01-HA27671. I want to keep the hydro as a spare for my Charger 12 Automatic. The transaxle is being used as a training piece so I can get familiar with what it takes to change out the axles. Any help would be greatly appreciated! TYIA

Edited April 19, 2019 by Ran d

[pfrederi 17,885]

Probably sealant or just age.  if you have all the bolts out I have used a brass drift pin and hammer from the other side to break it loose.

[953 nut 55,807]

A bit of gentle prying under the pump could help get it to move, rock it back and forth. 

16 minutes ago, Ran d said:

The axle came out of the transaxle. I can see the snap ring when I look inside the axle bore. It does not look broken.

You need to look at the axle splines at the end, chances are a few broke off allowing the snap ring to come off. In the future do not use a hammer, a puller is the only way to go.

[Ran d 24]

Nice puller. I did not think of that idea. If the inside of the transaxle looks usable, I may buy a couple of used axles from AtoZ and reassemble. The axle that came out did not have any damage to the splined end?

[Ran d 24]

Forgot to mention that I tried tapping a brass bar stock piece against the back side of the iron body and it was like hitting solid, like still a bolt in or something like that. I also tried prying. There is a place down were the shorter bolts go that I could get under slightly and again solid.

[953 nut 55,807]

51 minutes ago, Ran d said:

was like hitting solid, like still a bolt in or something like that.

Pictures please!        

[daveoman1966 3,762]

tHERE ARE 5 BOLTS HOLDING THE HYDROGEAR TO THE TRANS CASE..  Marked here by 'X".   

REMOVE THEM AND THE UNIT WILL SEPARATE...

Edited April 19, 2019 by daveoman1966

[Ran d 24]

Those are the bolts that I have already removed. I will attempt a first time picture. 

[Ran d 24]

Two pics showing five bolt holes:

[ztnoo 2,298]

1 hour ago, Ran d said:

I may buy a couple of used axles from AtoZ and reassemble

 

Just an FYI:

I noted in a different thread you had posted a question to A-Z Tractor.......in the Vendor section of the forum, I believe, about 3 weeks ago or so..

Just a heads up: Lincoln seldom checks here at Red Square, but he is very responsive to phone calls (leave message if he doesn't pick up), and a little less so with email, but certainly much, much more responsive than many other sellers.

The best way to contact him quickly is call.

His shipping is superb, so if you need something quickly he can usually fill the bill in a short time frame if he has the part(s) you require.

 

Steve

 

[Ran d 24]

He responded to my email request very quick.

[Ran d 24]

Daveoman1966.....could you post a picture of the output side of the hydrogear you posted a pic of earlier? It may help me better understand what I am dealing with. The manual I am using is a copy and the pics in it are not the best. Thanks!

 

 

[gt14rider 797]

[Ran d 24]

Don't see any reason why my hydrogear can't be removed with all the bolts out. At this point, I am suspecting possibly sealant or rust is causing this issue? BTW....I do not see any sealant at the parting line. Wondering if the round protrusion behind the gear is rusted into the bore in the transaxle?

[gt14rider 797]

Can you turn the other axel? If gears are locked up maybe locking pump gear. Maybe use a plastic dead blow hammer,  give it a couple wacks 

[daveoman1966 3,762]

5 hours ago, Ran d said:

Daveoman1966.....could you post a picture of the output side of the hydrogear you posted a pic of earlier? It may help me better understand what I am dealing with. The manual I am using is a copy and the pics in it are not the best. Thanks!

 

 

This what you mean...?  

 

 

Edited April 20, 2019 by daveoman1966

[Ran d 24]

The other axle can be turned freely. Thanks for the pic daveoman1966! As solid as this hydrogear appears to be, I am guessing that someone put it on without a gasket using sealant only. No matter what I do trying to get this off, it acts like all the bolts are still in and they are not. I have tried to persuade it tapping right under the hydraulic motor on the iron body that sticks above the transaxle case. Rock solid. Nothing is ever easy 😠

[pfrederi 17,885]

Take a stout kitchen knife ( i use one the tip snapped off) Use a hammer to drive the blade into the seam area at different spots. (Wear Eye protection if the blade breaks)  That combined with brass drift pin has always freed mine up.

[Ran d 24]

Finally got the hydrogear removed from the transaxle. I used an old kitchen knife as pfrederi suggested. I have attached some pictures showing the two assemblies as removed. I proceeded with the transaxle case separation and had to use the kitchen knife trick again. Was able to split the case apart and removed the gasket/sealant.

[Ran d 24]

Thanks to all who responded to my topic.

[daveoman1966 3,762]

Don't damage that screen....it is not replaceable.   Almost looks like someone used JB Weld as a gasket sealant.  

Anyway...if you intend to take the hydrogear completely apart...be CERTAIN to scribe marks for reassembly.  

Note, too that,,,if you take the pump housing off,...scribe it too for cortrect relocation / orientation.

The Charge Pump Housing also has to be fit ONE WAY...look a the NOTCH here.  If it has scores / gouges, sand on surface plate to remove

I bet the Piston Slippers look like this....  And the base of the Cylinder block too....refinish it smooth.

Thorughly flush ALL PARTS in Kerosene and apply Break-in Oil to contact surfaces when reassembling the unit....thats the red stuff.

[Ran d 24]

Thanks, daveoman1966! My concern, and reason for disassembly is to replace the axles. Your pictures will come in handy down the road if I decide to rejuvenate the pump. I was wondering where parts can be bought to do a pump? Also, is there any manuals, writeups etc for the gear motor from a hydrogear. I was thinking that if one of these motors has worn and lost efficiency that you could find someone to surface grind the cover to reduce the leakage caused by the gears wearing into the cover?

Edited April 21, 2019 by Ran d

[Sarge 3,463]

There is the full Sundstrand manual for these in the Manuals section here. Look up LJ Fluid Power in Michigan - they carry the parts for the Sundstrand transmission. Absolute, number one priority is cleanliness - no contamination allowed inside of a hydraulic system, ever. One particle can destroy a lot of parts and you will see evidence of this if you open up the pump. 

 

Sarge

[Ran d 24]

Got to looking over the axle that came out the other day and noticed the retaining ring groove had "rounded off" splines on the onboard side of the groove. One pic shows a spline with no rounding.

[pfrederi 17,885]

You need to replace the rounded off axle or drill it and put in a roll pin Older differentials did have the roll pin.(That is second choice)