Faceplated T56, high RPM grinding/lockout wtf?

[TonyG2]

A couple weeks ago, I got my T56 rebuilt, with 3rd and 4th faceplated. Today was the first time on the dragstrip. In all 4 of my passes, the 2-3 WOT powershift was amazing: fast and effortless, I still can't believe it.

But my 3/4 powershift resulted in a horrible grind in all 4 passes. I managed to get it into 4th on 2 passes. In the other 2, I didn't want to force it in, so I let off and coasted to the traps.

On the drive home from the dragstrip, transmission was whining for the first time...don't know if that means anything. Normal shifting is fine, however.

I thought that maybe the problem was due to a hot sticking clutch, so tonight I went out on the highway with a nice cooled off car. Did a 3rd gear pull...and went I tried to powershift @ 6500 rpms, it went in with a terrible grind.

Something is wrong.

I tried searching for this problem, grinding/lockout while powershifting a faceplated transmission. It seems to be non-existent.

Don't know where to begin looking, any ideas?

 

[Brutal Metal]

who did the tranny work for you?

 

[oldmodman]

Don't think that I am making fun of you by asking this question.

But most transmissions are shipped dry. No lubricant in them. Did you either fill it yourself or check the ATF level after you installed it?

I sure hope it isn't just dry.

 

[P49Y-CY]

whenever i hear about difficult shifting, esp at high rpm, i immediately think cable adjustment, not a transmission issue (unless like oldmodman says if it could be dry, then that would be really bad). what kind of cable adjustment hardware you are using?

 

[TonyG2]

Hanlon did the work. I can try raising the clutch pedal to give me more air gap, but its strange how 2-3 is always perfect while 3-4 grinds. I just hope the faceplates in 4 aren't burred up or ruined now. It happened a total of 5-6 times so far.

 

[TonyG2]

Fiore firewall adjuster, Steeda quick release quadrant, OEM cable. MM pedal height adjuster

 

[Brutal Metal]

Hanlon did the work. I can try raising the clutch pedal to give me more air gap, but its strange how 2-3 is always perfect while 3-4 grinds. I just hope the faceplates in 4 aren't burred up or ruined now. It happened a total of 5-6 times so far.

I also initially thought cable adjustment last nite when I saw the thread title but when I saw you say 1-2 is fine I didn't mention that.. Hanlon does Great Work call them tomorrow and ask advice..:beer:

 

[TonyG2]

I also initially thought cable adjustment last nite when I saw the thread title but when I saw you say 1-2 is fine I didn't mention that.. Hanlon does Great Work call them tomorrow and ask advice..:beer:

Yeah, Bob Hanlon was great. I actually brought the tranny to him in person and picked it up from his house. I'm just hoping that I didn't screw things up, and things will be OK after making some tweaks. I drained the ATF today. It did look a little dark. I'm going to refill with Mobil 1, raise the clutch pedal, and try it again.

Even though I had problems, I'm still giddy over the way it shifted from 2nd to 3rd effortlessly with accelerator pedal to the floor. I can never go back to a synchroed tranny now. Comparing the two is like comparing street tires to slicks.

 

[Brutal Metal]

consider a Synchromesh fluid for your T-56, ask Bob about that before you add Mobil1

 

[brian97cobra]

consider a Synchromesh fluid for your T-56, ask Bob about that before you add Mobil1

yes try gm syncromesh fluid

 

[TonyG2]

I already spoke to him about fluids. If I understood correctly, the faceplated gears are not that picky; you really only need to think about the synchros when selecting the fluid. He recommended regular Dex/Merc ATF. Mobil 1 is fine, Synchromesh is fine (he seemed to like Mobil 1 more). He didn't like RP Synchromax (which I used in my old T56, along with Synchromesh ). He also recommended another fluid which I can't remember now. It's not available in stores, you have to order it from Liberty, or one of those shops.

 

[WMD]

I Had a faceplated T56 done by Liberty, and never had a problem with shifting.
What clutch are you running?
A face plated trans should shift so smooth and fast it almost jumps to the next gear with the slightest pressure on the shifter.

 

[TonyG2]

The clutch is RAM powergrip HD with their billet Al flywheel

I'd like to think Hanlon did everything right, which makes me think there might be something structurally wrong. Maybe the case is twisted or something like that. 4th gear grinded before the rebuild, and I thought it was the synchros. But now there are no synchros.

I've been gradually raising the clutch pedal and tightening the cable to increase the air gap, it still grinds into 4th when I try to powershift. Regular street driving is still fine, I can upshift and downshift into 4th without a sound.

 

[WMD]

My buddy tried a Ram twin disk and we could never get it to release correctly. In fact I have never had luck with Ram ever since 5.0 days.
I used a RST/ RXT with mine and it was like butter.