fresh trans rebuild C-4 delayed shift from 2nd to 3rd [drive]

[Rockin Ken]

just got my car back from the transmission shop and there's a big delay between second and third at any speed.
there was nothing wrong with the transmission before.
I wanted the reverse valve body removed and the correct one put in.
To make things worse the water pump started leaking during my test drive.
any thoughts or knowledge would be appreciated, thank y'all

 

[rvrtrash]

Sounds like the shifter rod, between the shifter and the transmission, isn't adjusted correctly. Easy fix if that's it.

 

[Bobby]

I had the same problem with the C6 that was in my Mach 1. At the time, I didn't have any info on when the last time the fluid was changed nor how long it spent in storage. The tranny was leaking thru the shifter lever shaft seal. I replaced the shifter seal and put in fresh fluid and filter screen. The delay from second to third was eliminated with the new fluid. The old fluid looked fine and I could see no issues in the pan like shavings or discoloration. It might be worth a try. I took that opportunity to replace the pan with one that had a drain plug. The one thing to consider is that fluids have a shelf life whether its in the bottle or in the car. The bottled fluid will last longer as long as it has not been opened and exposed to air but fluids in the car are exposed to air and will break down over time whether the car is driven or not. That being said, its also possible that the tranny shop reused your old fluid......

 

[mrgmhale]

I would check the transmission Vacuum Modulator diaphragm to make certain it is getting intake manifold vacuum at the hosw that plugs into the modulator, and test the modulator to make certain the modulator diaphragm is not leaking or ruptured. If that is not the issue I would begin to look at the shift and kick-down rods for proper adjustment. The kick-down rod adjustment in the attached file ought to be relevant,

 

[Precision Transmission]

I'm going to assume that the reverse valve body was a full manual type. In most instances, the governor circuits in the case, or the governor itself would have been modified. Perhaps the governor valve is sticking. What did your trans shop have to do to swap in the conventional valve body? What is their assessment of the current shifting concerns?

As an aside, when you refer to a delay, do you mean a late shift, but with good feel, or a long dragged out 2-3 shift? Some manual valve bodies use a modified intermediate servo that is not compatible with a conventional valve body resulting in 2-3 shift concerns.

Did your manual valve body make use of the vacuum modulator to regulate line pressure to engine load? Most manual valve bodies I have worked on utilize full boosted line pressure at all times.

Some more info regarding your previous valve body, along with the work the transmission shop did would be helpful.

Regards
Don

 

[Rockin Ken]

I'm going to assume that the reverse valve body was a full manual type. In most instances, the governor circuits in the case, or the governor itself would have been modified. Perhaps the governor valve is sticking. What did your trans shop have to do to swap in the conventional valve body? What is their assessment of the current shifting concerns?

As an aside, when you refer to a delay, do you mean a late shift, but with good feel, or a long dragged out 2-3 shift? Some manual valve bodies use a modified intermediate servo that is not compatible with a conventional valve body resulting in 2-3 shift concerns.

Did your manual valve body make use of the vacuum modulator to regulate line pressure to engine load? Most manual valve bodies I have worked on utilize full boosted line pressure at all times.

Some more info regarding your previous valve body, along with the work the transmission shop did would be helpful.

Regards
Don

thank you for interest,
the shift point is not dragged out, but the shift from two to three takes like 3 seconds and the engine flares during the shift. this is not normal.
before the manual valve body was changed, it shifted like a hammer.

 

[Rockin Ken]

we will immediately test and check everything you suggested.
your expertise is invaluable!
and I thank you for your response

 

[piper62j]

I would pull the modulator out from the back of the transmission and make sure the small pin that connects the modulator to the valve body is there.. Sometimes, it falls out during an overhaul and the technician doesn't know it exists.. Take 5 minutes just to confirm... IMHO

 

[Rockin Ken]

thank you for interest,
the shift point is not dragged out, but the shift from two to three takes like 3 seconds and the engine flares during the shift. this is not normal.
before the manual valve body was changed, it shifted like a hammer.

I'm going to assume that the reverse valve body was a full manual type. In most instances, the governor circuits in the case, or the governor itself would have been modified. Perhaps the governor valve is sticking. What did your trans shop have to do to swap in the conventional valve body? What is their assessment of the current shifting concerns?

As an aside, when you refer to a delay, do you mean a late shift, but with good feel, or a long dragged out 2-3 shift? Some manual valve bodies use a modified intermediate servo that is not compatible with a conventional valve body resulting in 2-3 shift concerns.

Did your manual valve body make use of the vacuum modulator to regulate line pressure to engine load? Most manual valve bodies I have worked on utilize full boosted line pressure at all times.

Some more info regarding your previous valve body, along with the work the transmission shop did would be helpful.

Regards
Don

Can this transmission be modified back to normal? or should I have the guy just put it back the way it was with the manual valve-body, I have already paid $3000 and I don't know what to do now.