C4 tranny reverse valve body

west coast · 05-18-2009, 09:19 AM

I am looking at the kit from Broader performance it does not apply the low band in first gear. It seems like all of the other companys are also like this any body have problems with the reverse valve bodys in them or should I stay with a foward pattern. This is a stocker fox body style mustang. Thanks

Bill Harris · 05-19-2009, 07:00 PM

You shouldn't have any issue with a RVB that doesn't apply the reverse band unless you get stupid. The sprag in the C4 is pretty stout and not prone to failure like some of the GM three speeds. What it doesn't like is running it up to high speed in first, backing off and then tromping on the gas (i.e., stupid). That really slams the sprag from overrun to hold and if your gonna damage it, that would do it.

I like the "no engine braking" in first on mine, since I can run around the pits in first, back off the throttle and coast. I always apply the throttle very gently from coast though to prevent slamming the sprag.

I think there are reverse pattern valve bodies that do apply the reverse band in first, but that is tricky since the band has to be released going into second and the timing associated with that release can make for a really harsh shift (and trans damage) if it isn't done just right.

west coast · 05-20-2009, 09:28 AM

Thanks Bill had not thought about it that way coasting in the pits great point. Which valve body do you run? I am still researching but thr Broader do it your self kit is looking good. Thanks

Bill Harris · 05-20-2009, 12:04 PM

I have two valve bodies in two different transmissions. One is a Performance Automatic and the other is a JPT. Both operate very similarly and I haven't had any issues with either. The PA has a bit less 2-3 flair than the JPT, but I have different servos in the trans too. The PA has one of their billet servo setups while the JPT has a FoMoCo "H" servo.

RJ Sledge · 05-21-2009, 07:48 AM

Bill, you need to check the clutch pack clearance in the Direct and Forward drums. I shoot for .045 in the Direct and .025-.028 in the Forward. rj4004@yahoo.com RJ

Bill Harris · 05-22-2009, 08:09 AM

Hey RJ. I usually run about 0.060 in the direct with five frictions to reduce drag in first. Not sure it helps ETs, but it probably contributes to the flair on the 2-3. Next box I go through I'll try tightening it up. Thanks.

05-18-2009, 09:19 AM	#1
west coast Senior Member Join Date: Dec 2008 Location: Rainy Washington Posts: 609 Likes: 12 Liked 223 Times in 73 Posts	C4 tranny reverse valve body I am looking at the kit from Broader performance it does not apply the low band in first gear. It seems like all of the other companys are also like this any body have problems with the reverse valve bodys in them or should I stay with a foward pattern. This is a stocker fox body style mustang. Thanks

05-19-2009, 07:00 PM	#2
Bill Harris Member Join Date: Mar 2002 Location: Ooltewah, TN Posts: 421 Likes: 13 Liked 26 Times in 13 Posts	Re: C4 tranny reverse valve body You shouldn't have any issue with a RVB that doesn't apply the reverse band unless you get stupid. The sprag in the C4 is pretty stout and not prone to failure like some of the GM three speeds. What it doesn't like is running it up to high speed in first, backing off and then tromping on the gas (i.e., stupid). That really slams the sprag from overrun to hold and if your gonna damage it, that would do it. I like the "no engine braking" in first on mine, since I can run around the pits in first, back off the throttle and coast. I always apply the throttle very gently from coast though to prevent slamming the sprag. I think there are reverse pattern valve bodies that do apply the reverse band in first, but that is tricky since the band has to be released going into second and the timing associated with that release can make for a really harsh shift (and trans damage) if it isn't done just right. __________________ Bill Harris ex 2172 STK ex 2272 S/S

05-20-2009, 09:28 AM	#3
west coast Senior Member Join Date: Dec 2008 Location: Rainy Washington Posts: 609 Likes: 12 Liked 223 Times in 73 Posts	Re: C4 tranny reverse valve body Thanks Bill had not thought about it that way coasting in the pits great point. Which valve body do you run? I am still researching but thr Broader do it your self kit is looking good. Thanks

05-20-2009, 12:04 PM	#4
Bill Harris Member Join Date: Mar 2002 Location: Ooltewah, TN Posts: 421 Likes: 13 Liked 26 Times in 13 Posts	Re: C4 tranny reverse valve body I have two valve bodies in two different transmissions. One is a Performance Automatic and the other is a JPT. Both operate very similarly and I haven't had any issues with either. The PA has a bit less 2-3 flair than the JPT, but I have different servos in the trans too. The PA has one of their billet servo setups while the JPT has a FoMoCo "H" servo. __________________ Bill Harris ex 2172 STK ex 2272 S/S

05-21-2009, 07:48 AM	#5
RJ Sledge Senior Member Join Date: Jun 2007 Posts: 783 Likes: 498 Liked 288 Times in 90 Posts	Re: C4 tranny reverse valve body Bill, you need to check the clutch pack clearance in the Direct and Forward drums. I shoot for .045 in the Direct and .025-.028 in the Forward. rj4004@yahoo.com RJ

05-22-2009, 08:09 AM	#6
Bill Harris Member Join Date: Mar 2002 Location: Ooltewah, TN Posts: 421 Likes: 13 Liked 26 Times in 13 Posts	Re: C4 tranny reverse valve body Hey RJ. I usually run about 0.060 in the direct with five frictions to reduce drag in first. Not sure it helps ETs, but it probably contributes to the flair on the 2-3. Next box I go through I'll try tightening it up. Thanks. __________________ Bill Harris ex 2172 STK ex 2272 S/S