Need Help with Loose Differential Flange on 308 GTS

Hi everyone,

I recently replaced the oil seal on the differential of my Ferrari 308 GTS while the engine is out. The process went smoothly, and I followed all the necessary steps, including correctly torquing the flange bolt and ensuring the tab washer is facing the correct way.



However, after reassembling everything, I noticed that the differential flange still feels loose. The bolt is torqued to spec, and the tab washer is positioned properly, but there’s still play in the flange. I didn't bother checking before dissasembly, so I'm not sure if it was there before or not.

I've attached a video showing the issue. Has anyone encountered this before? Could this be due to worn splines on the flange or shaft, bearing misalignment, or possibly an issue with the spacer or shim setup? Any advice or suggestions would be greatly appreciated!

I replaced the oil seal on the other side first and it is solid, there is no play whatsoever.

More importantly, should I bother with this or leave it as is?

Thanks in advance for your help.

 

Its normal to be loose. If the other side has no movement thats what Id be worried about.

 

Thanks for the insight! I’m curious to understand more about why it would be an issue if the other side had no movement. From where could this issue originate, and what could it indicate about the differential’s condition? You can see this in the video below:


Also, would this be considered a significant problem that should be addressed before I reinstall the engine, or is it something that can be monitored and dealt with later if necessary? Appreciate your advice!

 

The flange is connected to the differential side gear. It needs to move.
To be honest I have questions as to your observation one had no movement. I have never in 40+ years ever seen that and if it is the case I would strongly suspect it was as a result of human interaction. Aside from the output flanges and seals was the transaxle or differential disassembled or worked on in anyway?

 

This can be seen in the video above, there is no play whatsoever.

In terms of human interaction, I simply changed the seals and it had the "OEM yellow paint" so I don't believe anyone was there before me.

 

So to clarify, you think the loose is not from the flange to shaft connection, but internally from here?
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How can it be anything else? The side gears are not a close fit to anything except the output flange. I have no doubt the looseness of the flange is being misjudged.
Put the car together.

 

Just the final bits and bobs, hopefully in the next couple of weeks I will be posting here of the car running