H151F Replacing Synchros on a '96 J80

[mudgudgeon]

I think I ended up getting it from amayama.com however it did not solve my dump truck like shifting, new synchros H151f

Did you try changing out the oil?

These boxes are known for clunky shifting. Very frequently ~$50 of fresh oil of the right type will make a hell of a difference.

 

[Magic Spool Bus]

Did you try changing out the oil?

These boxes are known for clunky shifting. Very frequently ~$50 of fresh oil of the right type will make a hell of a difference.

I have tried multiple types of oil and currently have amsoil in it. Never did changing the oil change gearbox characteristics. 2nd and 5th gear are always an issue but again I could be asking too much from an old gearbox.

 

[mudgudgeon]

I have tried multiple types of oil and currently have amsoil in it. Never did changing the oil change gearbox characteristics. 2nd and 5th gear are always an issue but again I could be asking too much from an old gearbox.

That's a shame. Changing oils has been enough to make a marked difference in the 80s I've had.

There's no oil that's going to fix some synchros. If they are done, they are done.

My first 80, I changed the oil not long after I bought it to a quality oil that met Toyota specs. I immediately started having difficulty shifting.
I was close to pulling the trigger on a $2500 gearbox rebuild, and someone suggested changing to VMX-M. Problem fixed in all but the coldest weather.

Toyota made changes to the synchros in later 80s

 

[Magic Spool Bus]

That's a shame. Changing oils has been enough to make a marked difference in the 80s I've had.

There's no oil that's going to fix some synchros. If they are done, they are done.

My first 80, I changed the oil not long after I bought it to a quality oil that met Toyota specs. I immediately started having difficulty shifting.
I was close to pulling the trigger on a $2500 gearbox rebuild, and someone suggested changing to VMX-M. Problem fixed in all but the coldest weather.

Toyota made changes to the synchros in later 80s

I have heard of this VMX-M but if I remember correctly I couldn’t source that oil here in the USA

 

[mudgudgeon]

I have heard of this VMX-M but if I remember correctly I couldn’t source that oil here in the USA

I think the key is slightly lighter weight oil, and friction modified additives