Diff Case/Speedo Drive Case Sealing

[LucasDunkley 0]

Hi everyone. Doing some winter maintenance on my car and addressing a couple of small oil leaks.

 

Im changing the driveshaft seals anyway as I’ve got a leak from the RH shaft seal but I think I could also have a leak coming from the diff case.

 

My question is whether RTV/instant gasket should be used between the diff case and gearbox face, and the speedo drive case? From what I understand it has the chance of affecting the bearing preloads, etc.

 

Any advice would be greatly appreciated.

[Ozymandis 104]

Use it, get a decent quality slop not cheaps*it though.

[Tom Fenton 1,650]

RTV silicone, I use the Wurth stuff. Big thing is to make sure you allow it to cure fully before it sees any oil, as otherwise it doesn't cure and goes all mushy instead.

[DamirGTI 366]

Myself i mooved off the RTV type sealants quite a bit , especially for gearboxes .

For gearbox case/halves sealing, i prefere synthetic non-setting sealants like Curil T (“T” stands for transmission), Loctite 518 , Hylomar Blue, or alcohol based Shellac sealant .

[LucasDunkley 0]

Thanks for the replies, Sounds fairly unanimous.

 

I’ll make sure to apply a little when building it back up. I think I’ll be using loctite si flange sealant I’ve used on my engine or hylomar as Damir suggested

 

@DamirGTI I’ve also used hylomar blue rebuilding a classic mini transmission. Unusual stuff but works well.

[petert 641]

ThreeBond 1211 for me.

[DamirGTI 366]

5 hours ago, LucasDunkley said:

 

@DamirGTI I’ve also used hylomar blue rebuilding a classic mini transmission. Unusual stuff but works well.

Indeed ! i used it as an road trip fix on some pretty peculiar areas such as brake caliper bleed screw leak (cause of poor broken nipple removal and thread repair) and it sealed it no problem .. also as an sealing aid along with cam cover gaskets for certain commons oil leak prone engines .

 

In gearboxes , i found on a few occasions from previous rebuilds , strips and bits of RTV gasket clogging up the oil drillings/passages in the input/output shafts .

Unlike on the engine crankcase where the specks of the RTV usually collects on the oil pickup mesh and stays there in the gearboxes theres nothing to block them entering the shaft oil passages .

 

Mating surfaces on the gearbox halves are also finely machined , could amost seal with no sealant at all , OE type of seanant i think they used was Shellac . 

 

Only part of the BE gearboxes where liquid falange sealants tend to sprung a leak and not be as good i've found is the fifth gear steel cover .

Only there i use little dab of RTV .