Fresh rebuilt Hemi 4 speed and shifter hard to shift fast

[Lloyd Lind]

So everything is rebuilt but very stiff to shift. I can force it to shift fast but I have to be very deliberate to make sure I get it to go in to each gear under power and not miss a shift. Does anyone have any tips on how to get a fresh rebuild to start shifting easier....sooner. I have the recommended gear oil in it but I'm thinking of switching to 1/2 automatic transmission fluid to help it out. It's just not much fun shifting through the gears as it stands.

[dodj]

IMO, switch to 100% ATF4. I switched from gear oil 30 years ago. Shifts far better.

[Chryco Psycho]

are you using GL 4 or GL 5
GL 5 is too slippery for the syncros to grip properly

[Lloyd Lind]

Gl4 75/90 now.

I know better than to run gl5, won't work with yellow metals or shift with stock sincros...too slippery. I also know better than To ruń 100 % automatic transmission fluid as well. I'm thinking a change to gl4 140 or 50% automatic fluid or both....at least until it breaks in some.

[734406PK]

 I had a Dodge Ram 3500 with the NV4500 manual transmission in it and it was very difficult to shift especially when cold. After a few GL-4 oil changes without much improvement, I used Amsoil synthetic and WOW what a difference!. Hot, cold it was all good! It might be worth a try.
This is what was spec'd for the NV4500 at the time:
https://www.amsoil.com/shop/by-product/transmission-fluid/manual/manual-transmission-and-transaxle-gear-lube-75w-90/?code=MTGQT-EA.

You might also want to use try the synthetic ATF:
https://www.amsoil.com/shop/by-product/transmission-fluid/automatic/oe-multi-vehicle-synthetic-automatic-transmission-fluid/?code=OTFQT-EA

Check the spec for your application, but its worth a try. 

[RUNCHARGER]

GL4 should be fine. Check shifter and clutch adjustment. Other than that give it a few hundred miles. It should shift as fast as you can pull the lever.

[BIGSHCLUNK]

A buddy of mine ended up doing a little filing - something to do with chinese gears. HEMI RR 

[HP_Cuda]

This is what you want, works the charm:

https://www.redlineoil.com/mt-90-75w90-gl-4-gear-oil

[Lloyd Lind]

I will try this, thanks a lot! Did not know you could buy this from Jegs or Summit and I did not know a distributor. I'm ready to dump my conventional break in oil after a thousand miles and two changes so I may see what they have for motor oil as well.

[aussiemark]

This is what you want, works the charm:

https://www.redlineoil.com/mt-90-75w90-gl-4-gear-oil

I was thinking the same thing had difficulty with one car (non Mopar) kept missing second to third and grinding (not every shift just at high rpm 6800) drained flushed and refilled with this oil and never missed another shift worth a try.

[RUNCHARGER]

Did you check for clean clutch disengagement and shifter rod adjustment?

[dodj]

I also know better than To ruń 100 % automatic transmission fluid as well.

It was a recommendation from Chrysler to use ATF. And in later service manuals.  I need to replace the reverse lever o-ring soon and I will be using the oil 4406PK posted the link on for the re-fill. Probably better than ATF.