R154 Gearbox Leaking from rear shaft seal

**rogue-vl** · 09-10-2009, 09:07 PM

As the title states the rear seal (for the tail shaft yoke) is leaking gear oil, has continues after replacing the rear seal with a new genuine Toyota one, any ideas what else I could do?

**2jzhilux** · 09-10-2009, 09:58 PM

Any marks on the tailshaft yoke that look like they could be grabbing the seal?
Uni joints not siezed/stiff?

**pandaah** · 10-10-2009, 02:04 AM

you obviously made sure the tailshaft and inside the tailend of the gearbox was very clean before installing the new seal and reinstalling the tailshaft?

**rogue-vl** · 10-10-2009, 10:37 AM

Complete tail shaft has been rebuilt and modified to suit the commodore, commodore shaft lengthened new unis and the yoke that came with the box.
Just another thought would the yoke likely to be tapered? perhaps the yoke isn't sitting far enough into the back of the box. Anyone have an idea how far the shaft should sit in the back of the box?

**2jzhilux** · 10-10-2009, 11:21 AM

I dont think there is a specific measurement but id say you would want at least half of the total length of the slip yoke inside the box.
If this is in a commodore what are your driveline angles like?

JP · 10-10-2009, 05:51 PM

have you checked that the rubber gasket that sits below the shifter housing is not leaking?

When that leaks it can look like a leaking output seal.

**mxracer92** · 10-10-2009, 09:00 PM

i had the same issue when i 1jz/r154 my hilux , i tryed everything to fix , tighter seals , rebush output shaft , 2x seals .. still did it .. i think it has something to do with alignment of the box,motor,tailshaft.

i ended up just putting in a getrag 6 speed ( that fixed it ~!!)

**rogue-vl** · 11-10-2009, 05:50 PM

Thanks JP I'll have to get under her and have another good look, and as for the drive line angles...I believe there pretty good, but again something else I will investigate.

**DrNick** · 12-10-2009, 01:04 AM

I'm pretty sure the yoke that fits into the R154 is not tapered, I remember it looking a bit precarious when I installed it. That oil seal really is the only thing that does the job so if the problem doesnt turn out to be elsewhere then theres no choice but to remove it and clean it up and try again

**allencr** · 12-10-2009, 03:18 PM

Seals need good surfaces to be mounted in and to run on, and also need to have a minimum amount of shaft movement.
Bad tailshaft bearing? New seals have a lot of flexibility so the bearing would have to be pretty sloppy to leak.
Also, the splines on some yokes aren't machined in a blind hole, but go all the way through & have a welsh/core/freeze plug that keeps the lube in.