Getrag 245 - speedo drive disassembly

[zambo]

I’m needing guidance on removing the metal bush at the top of the lower assembly (as opposed to the upper gear drive shaft) in order to replace the internal seal. 
 

The bush presents with the small grooves opposite each other but wondering how best to approach this. There was a thread years back but it didn’t appear to resolve this issue. 
 

Thanks as always. 

[jgerock]

As I recall, the speedometer drive gear pieces have a very tight interference fit. Think I used two pair of pliers to twist them apart.  Before dismantling anything, please make sure all the pieces are still available.  The main o ring seal is the easiest to replace, the bush and inner seal the hardest.  If you speedometer gear literally falls out of the transmission, then your old parts are worn and need replacing.

[jgerock]

Two older pictures. Not 100% sure, but think the 242 and 245 share speedometer bushing parts.

[BLUNT]

This is how a previous owner dealt with the problem on an Auto we just bought.

Guy touted how "everything was done correctly on this one" as we winched it on a trailer

[zinz]

Considering how the O-ring on an automatic's speedo drive is a massive PITA to install correctly (they almost ALWAYS leak afterwards)  all that RTV probably worked pretty good. 

 

Ed

[jgerock]

6 hours ago, BLUNT said:

This is how a previous owner dealt with the problem on an Auto we just bought.

Guy touted how "everything was done correctly on this one" as we winched it on a trailer

At least they wiped off the area in direct vicinity before glopping on the RTV.  That looks like a real mess😔

[Mark92131]

On reassembly, make sure you line up the middle of the square cutout in the Adapter (#21) with the clamping bolt (#16).  The PO of my Getrag 245 transmission aligned the left edge of the cutout with the clamping bolt and while torquing it down, mushroomed the edge of the Adapter cutout preventing me from pulling out the speedo cable.  It took a couple of hours to pull the end of the cable out of the Adapter and remove the burrs so everything fit without interference.

 

Mark92131

[Mark92131]

 

13 hours ago, jgerock said:

Not 100% sure, but think the 242 and 245 share speedometer bushing parts.

 

Yes, you are correct.  The 242 and 245 Getrag transmission speedometer drive gear, bushing, adapter, shaft seal and O-ring have the same part numbers.

 

Mark92131

[zambo]

13 hours ago, jgerock said:

As I recall, the speedometer drive gear pieces have a very tight interference fit. Think I used two pair of pliers to twist them apart.  Before dismantling anything, please make sure all the pieces are still available.  The main o ring seal is the easiest to replace, the bush and inner seal the hardest.  If you speedometer gear literally falls out of the transmission, then your old parts are worn and need replacing.

Thanks for the comment it’s an interference fit - I’ll get some soft jaws for the vice out and pliers and see if I can separate it from the main body.
 

The drive gear section shaft fits in the seal (#20) but isn’t that tight in my view to stop a leak. I’d rather do it once and hopefully then forget about it. The seal looks generic enough in size so will see what we can do. 

[zambo]

Update - the bush wasn’t as hard to remove as I initially thought … just as suggested a pair of vice grips on one and a screwdriver in the side slot of the bush gets it spinning and then some pliers to remove. The bush looks in good shape for reuse. 
 

The internal seal on the other hand was an sob to get out. Used a bit of heat and some small screwdrivers and pin punches and got there in the end. But a bit of a mission for sure. 
 

Just curious is that a standard radial shaft seal to the size 8x14x6 specified in the Realoem listing? Thanks as always. 
 

P.S. I always believed that with an oil seal the lip/channel on the seal, faces the direction of the oil source. And I say this having just finished the three main seals on the 245.
 

This seal inserted in the adapter under the bush, faces the other way with the drive shaft entering through what I would refer to as the top face of the seal.

It’s true that the drive shaft is a neat (not tight) fit into the bush and then enters the seal further down the adapter so maybe with the neat fit and presence of a seal is enough to stop fluids passing through the internals of the adapter. 

Edited June 23, 2023 by zambo