TCI VB kit trouble 4R70W

[0302Cobra]

I just installed a TCI torque converter and Trans Scat valve body kit into my 1998 GT 4R70W transmission. I used the middle level called "street" on the instructions. The tranny will not shift into 3rd. It runs through 1st and 2nd fine in drive and when manually shifted. It runs fine when left in 2nd. When in drive it really nose dives when you let off the accelerator. It pulls back on the engine enough to almost bring the car to a stop. I believe one of the valves in the VB or an actuator has slipped out or is hung up. Any ideas before I pull it out again?

I am new to this forum, but was told you guys have the best info for Sn-95 GTs.

 

[Stark77]

I would check your shift linkages before you pull the whole tranny. Are you using stock shifter or a B&M Hammer?

 

[CobraRed_96_GT]

Yeah, need more shifter info. Sounds like a clutch-pack or accumulator problem. Would be a major one. Has it been fine before and just started doing it? Or since being built it's doing that?

 

[0302Cobra]

I just installed the kit and had the problem immediately on the initial test drive. I am using the stock shifter and have checked the shifter linkage. As it properly goes into P,R,N,1,2, and really it will go into D it just will not get out of second, I do not think it is the linkage.

 

[nyuk98gt]

0302Cobra:

Please confirm: the transmission will shift OK manually (so you can get 3rd and OD (4th)) but it will not shift into 3rd if the selector is put in D.

Next, please list your mods so we know what we are dealing with.

Do you have a handheld flasher or other means to change the tune? Did TCI recommend different shift and lock points for the new converter? If so, how to they implement those changes? The shifting is done according to functions in the PCM calibration, not hardware.

Other things:

Is the VB torqued to the correct spec? If it is loose, shifting can be affected (since ATF is not going where it is supposed to go).
Is the 2-3 accumulator piston installed OK? Is the bore nice and smooth?
The electrical connector (L-shaped thing) that snaps onto the bottom of the VB is clipped securely at the solenoids (all the way along the length)?
Fluid level is OK?

I will check my ATSG and shop manual tonight but the problem has to be hardware since the car was shifting OK before the new VB and converter.

Stay tuned for more questions.

Chris

 

[0302Cobra]

Chris thanks for looking at this. The transmission will not go into 3rd or 4th under any conditions. I am using the stock shifter so I can select 1st and 2nd , but only have D for 3rd and OD. In D it will shift properly through 1 and 2, but will not go into 3rd and when it gets in 2nd gear in D it will nose dive. This only happens in D.

The engine is a stock block with Fox Lake stage 3 PI heads and a bullitt intake. Other than a built rear it is pretty stock.

I do not have a handheld. The car was previously tuned on a dyno and has a Diablo chip. TCI did not say it was necessary to change the shift points. I am having the block built and the car tuned in a few weeks so I was not planning on a tune after this install.

The VB is correctly torque. This was triple checked on the install. The 2-3 accumulators is likely the problem. I think it has either popped out or is stuck. The bore looked great when I installed the new piece. I have not rechecked the connector, but will before I take it apart. Fluid is correct.

I really think it is the actuator or a valve that has popped out or is hung up. I cannot get to the auto hobby shop until Wednesday to take it apart.

I was hoping someone had this same problem before and knew why. I am worried that when I open it up it will look fine and then I will not know what to do next. Waiting to get in there is driving me crazy.

Thanks for the help.

 

[nyuk98gt]

0302Cobra:

You're welcome. I am glad to assist if I can (and, for the record, I have received lots of help from other Mustangers) - we're all in this together!

According to my trusty ATSG, it looks to me like shift solenoid 2 has failed.

Page 14, shift solenoid 2 (SS2) always off, here is what you get:

Gear commanded 1, gear selector in OD, gear obtained 1;
Gear commanded 2, gear selector in OD, gear obtained 2;
Gear commanded 3, gear selector in OD, gear obtained 2;
Gear commanded 4, gear selector in OD, gear obtained 1;

Gear commanded 1, gear selector in D, gear obtained 1;
Gear commanded 2, gear selector in D, gear obtained 2;
Gear commanded 3, gear selector in D, gear obtained 2;
Gear commanded 4, gear selector in D, gear obtained 1;

Gear commanded 1, gear selector in 1, gear obtained 1;
Gear commanded 2, gear selector in 1, gear obtained 1;
Gear commanded 3, gear selector in 1, gear obtained 1;
Gear commanded 4, gear selector in 1, gear obtained 1.

"Gear commanded" means by the PCM (computer).

This might be a simple thing of not snapping the L-shaped connector onto SS2. Believe me, this is easy to do (that is, it's easy to NOT snap it in place).

Please post back with an update. Enquiring minds want to know, lol.

Chris

 

[CobraRed_96_GT]

Great point Nyuk

 

[0302Cobra]

It is the solenoid. Unfortunately when I took it apart it appears that I have shredded the transmission during the test phase. Now I am beyond my ability to fix it and will be going to a pro. Bright side here is I learned a lot, the loss was not too much $, and now I will get a fully built transmission. I am also lucky that now I have a reason to drive my '99 Cobra every day for a couple weeks.

Lessons learned:
1) A shift kit is not worth the trouble to do yourself.
2) Buy an assembled and tested TB or get a pro to install the kit.
3) If the car has even the smallest problem STOP and push it back if necessary.

Thanks again for the help. I will try and get some pics up one day and let you guys know my future plans.