Minor transmission issue (see video)
06-24-2013, 02:51 PM
#1
Minor transmission issue (see video)
A few details on my car....
'69 Road Runner
440
TF727 w/reverse manual valve body
2800 stall
3.91 gears
Under 50% throttle, the trans shifts great and I have no issues
However, above 50% throttle, during the 2-3 shift, I get a 300-500 RPM spike before 3rd actually engages
Here's an old video that will give you an idea what I'm talking about:
Fast Forward to 4:33, 5:50 and 8:55
Listen closely to the 2-3 shift and you'll hear the RPM spike....
It feels and sounds just like power shifting a manual trans.
There's no slippage in any gear when I flash it from low RPM's and the spike during the 2-3 shift under hard acceleration seems to be the only issue.
I'm hoping it's just a simple band adjustment, but open to other suggestions before I pull the pan.
'69 Road Runner
440
TF727 w/reverse manual valve body
2800 stall
3.91 gears
Under 50% throttle, the trans shifts great and I have no issues
However, above 50% throttle, during the 2-3 shift, I get a 300-500 RPM spike before 3rd actually engages
Here's an old video that will give you an idea what I'm talking about:
Fast Forward to 4:33, 5:50 and 8:55
Listen closely to the 2-3 shift and you'll hear the RPM spike....
It feels and sounds just like power shifting a manual trans.
There's no slippage in any gear when I flash it from low RPM's and the spike during the 2-3 shift under hard acceleration seems to be the only issue.
I'm hoping it's just a simple band adjustment, but open to other suggestions before I pull the pan.
06-24-2013, 05:02 PM
#2
That's where I would start. Pull the pan and adjust the bands. Drain it into a clean container& re use the fluid.. If the problem is fixed. Use your judgment to change the fluid. could be the clutch pack too ? Could be throttle pressure adjustment on the valve body With a full manual trans ? Check with the guy who built it.. Might be able to get some adjustment figures on B&M web site.. for the throttle pressure screw
Last edited by TVLynn; 06-24-2013 at 05:09 PM.
07-07-2013, 08:29 PM
#3
I adjusted the band last night.
Took about ~3.5 turns to firm, torqued to 72 in/lbs., then went ~2.5 turns out and locked it down.
Noticed a slight difference, but there's still a bit of flair.
Here's another video from today...
Listen closely to the 2-3 shift
Fluid is fresh as it was changed with the tailshaft bushing not too long ago.
Unfortunately, I found out that the guy who built it has passed on
Took about ~3.5 turns to firm, torqued to 72 in/lbs., then went ~2.5 turns out and locked it down.
Noticed a slight difference, but there's still a bit of flair.
Here's another video from today...
Listen closely to the 2-3 shift
Fluid is fresh as it was changed with the tailshaft bushing not too long ago.
Unfortunately, I found out that the guy who built it has passed on
07-08-2013, 06:52 AM
#5
However, after a bit of research, it seems I may have used the wrong adjustment spec
I went 2.5 turns out, which is apparently the stock spec.
After reading through a few reverse manual valve body installation procedures (I'm not sure which model I have btw), it appears I have it turned out a bit too much
Now, how would I go about identifying what ratio band lever I have?
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