Hey guys

i think I may finally be at a point where I can stop asking questions. But I wanted to run one more thing past you all.

after my zf5 swap I was happy with it and I was finally at a place where I was getting buttery smooth shifting and very minimal problems. I had a lot of noise so I changed over to some amsoil torque drive. I put 4.5 quarts just to help with noise.

The second I took it out for a spin it was shifting beautifully. Nice and smooth. BUT, I cannot downshift into 2nd gear now. It grinds the living crap out of it. I have to be doing 13 mph or under in order to shift from 3rd to 2nd without grinding. It doesn’t matter if I try to bring it into neutral, and double clutch, or shift it like an unsyncronised. It just won’t let me into gear. shifting up, from first to 2nd causes 0 issues, it goes beautifully. Before, when I would downshift I could hear the syncro spooling up and it would go into gear ok after it matched. Now, I can’t say that I hear the syncro spooling much.

What does this sound like? I mean before the oil change the only time it would grind was if real cold.

If I somehow lost a syncro, how hard would it be to simply just replace that one. I don’t have the time to rebuild the whole trans. But I think I could manage replacing one syncro. I seen online you can just but they one ring. But let me know how hard that is.

Also, what causes syncro wear? As far as I was aware the trans was rebuilt 10k before I bought it to swap with my E4oD. And like I said every other gear is awesome shape. I don’t slam gears either, I shift like a grandpa.

any help would be great!

 

https://bobistheoilguy.com/forums/th...stions.350594/


FYI, I run this in mine with no issues: https://www.redlineoil.com/mtl-75w80-gl-4-gear-oil

 

I might risk it and out the old fluid back in. I still have it in a drain pan. If it worked before it’s gotta work now… right?

there was no metal in it it was simply preventative maintenance as a flush from the new trans.

 

If the oil was the fault or the problem
It would grind going into any gear, not just second
Synthetic Mercon V, and a new synchro

 

Tried to rev match too? 3-2 downshift on these is pretty tough as the gearset is just so damned heavy plus the syncros are all single cone.

What engine is in front of this and rear gear ratio? In my 7.3 I only drop back to 2 when at dead stop. I have enough inertia from the clutch/fly and vehicle momentum to pull along around 1000rpm which is about as low as 7-9mph I guess.

Without a receipt, I would assume it has not been rebuilt.

Syncro for 2 is in the middle of the gearset. 5/R on back. 3/4 on front. So if you replace 2, may as well do 3 and 4 while open. R rarely shows wear, like 1. 5 is hit or miss.

 

Looking at a trans rebuild or overhaul to replace the 1-2 synchro
I sure would be replacing the 3-4 synchro while in there
The cost is not effective IMO
Get ready for a shock when pricing synchros for an old ZF

 

https://cmgearworks.com/?s=zf+5+part...&type_aws=true

https://ampdistributing.com/collecti...d-transmission

https://ampdistributing.com/collecti...d-transmission

 

get a set of synchro springs, bearing and that plate
i had one fly across the shop into the abyss