Setting base TV with pressure gauge
- Thread starter VIN7
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RmvBfrFlght
Well-Known Member
- Joined
- Sep 28, 2007
OK, was lining some pictures up for the post. Have to have pictures 
Goes without saying that the TV cable adjustment and IAC steps adjustment need to be made first. These affect the TV plunger location.
To set up the TV lineup measure the length of the plunger that protrudes from the bushing. This is done with the throttle body in the idle position and the TV cable connected, see to the left in picture. In my case it was 0.668", YMMV.
Once that dimension is written down drop the valve body. In the above picture note where the TV valve flanges are located relative to the port, that is the end goal. Here is a pic of the VB showing this:
Easy to make out the flange on the left of the port. The one on the right of the port is there, just a little harder to see. Just to the right of the port is the conical spring, with the next opening over showing the end spring (silver). More on these further in this post.
What needs to be done is to match up the plunger spring with the TV valve spring(s) to center the flanges in the port with the TV plunger pushed in to the idle length. I used the dial calipers locked to that length to press in on the plunger. While observing the location of the flanges within the port. While doing this be sure to use the roll pin to hold the bushing in place.
It is better to err with placing the flanges further to the right. This allows for immediate line pressure rise on tip-in. However, don't go too far as that will allow TV fluid to increase the pressure at idle. If you can see past the left flange, that is too far.
While adjusting the springs, also check that prior to the plunger being even with the bushing (fully depressed as in WOT), that the TV valve bottoms on the casting. Can see this through the opening (see above pic) where the end spring is.
For springs I used:
Plunger spring: McMaster Carr # 9657K392:
Steel Compression Spring, Zinc-Plated Music Wire, 2.00" Long, .480"OD, .055" Wire
Conical spring: is a modified McMaster Carr # 1692K22:
Type 302 Stainless Steel Conical Compression Spring, .625" Long, .48" Large OD, .187" Small OD, .029" Wire Diameter
End spring: ball point pen spring that was shortened some and adjusted for the above results.
Here is the conical spring as delivered then modified. The small end goes onto the TV valve first. The reason it needs to be conical (or tapered) is that the coil bind height is very short. There isn't enough room (distance) in the valve body for a regular spring. It will coil bind and prevent full TV, resulting in low line pressure.
Then the full line up:
On the TV valve can see the two flanges to line up with the port just to the left of the conical spring. The plunger spring was used as delivered. With the TV valve springs tweaked and adjusted to provide the proper position of the TV valve flanges to the port.
Once the transmission is reassembled check the TV adjustment. It may need to be tweaked a little as things won't be in the exact same spot as they were before dropping the VB. And before putting the pan back on can double check the plunger location along with WOT fully depressing the plunger flush with the bushing.
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Goes without saying that the TV cable adjustment and IAC steps adjustment need to be made first. These affect the TV plunger location.
To set up the TV lineup measure the length of the plunger that protrudes from the bushing. This is done with the throttle body in the idle position and the TV cable connected, see to the left in picture. In my case it was 0.668", YMMV.
Once that dimension is written down drop the valve body. In the above picture note where the TV valve flanges are located relative to the port, that is the end goal. Here is a pic of the VB showing this:
Easy to make out the flange on the left of the port. The one on the right of the port is there, just a little harder to see. Just to the right of the port is the conical spring, with the next opening over showing the end spring (silver). More on these further in this post.
What needs to be done is to match up the plunger spring with the TV valve spring(s) to center the flanges in the port with the TV plunger pushed in to the idle length. I used the dial calipers locked to that length to press in on the plunger. While observing the location of the flanges within the port. While doing this be sure to use the roll pin to hold the bushing in place.
It is better to err with placing the flanges further to the right. This allows for immediate line pressure rise on tip-in. However, don't go too far as that will allow TV fluid to increase the pressure at idle. If you can see past the left flange, that is too far.
While adjusting the springs, also check that prior to the plunger being even with the bushing (fully depressed as in WOT), that the TV valve bottoms on the casting. Can see this through the opening (see above pic) where the end spring is.
For springs I used:
Plunger spring: McMaster Carr # 9657K392:
Steel Compression Spring, Zinc-Plated Music Wire, 2.00" Long, .480"OD, .055" Wire
Conical spring: is a modified McMaster Carr # 1692K22:
Type 302 Stainless Steel Conical Compression Spring, .625" Long, .48" Large OD, .187" Small OD, .029" Wire Diameter
End spring: ball point pen spring that was shortened some and adjusted for the above results.
Here is the conical spring as delivered then modified. The small end goes onto the TV valve first. The reason it needs to be conical (or tapered) is that the coil bind height is very short. There isn't enough room (distance) in the valve body for a regular spring. It will coil bind and prevent full TV, resulting in low line pressure.
Then the full line up:
On the TV valve can see the two flanges to line up with the port just to the left of the conical spring. The plunger spring was used as delivered. With the TV valve springs tweaked and adjusted to provide the proper position of the TV valve flanges to the port.
Once the transmission is reassembled check the TV adjustment. It may need to be tweaked a little as things won't be in the exact same spot as they were before dropping the VB. And before putting the pan back on can double check the plunger location along with WOT fully depressing the plunger flush with the bushing.
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I'd be interested in hearing the details. I've spent the last few weeks studying the hydraulic circuits and definitely agree that there is a lot more to it than the factory set procedure. One other thing I didn't mention, I reused the flat Trans Go shim that goes inside the spring. It allows the plunger to act fully on the throttle valve before the spring fully compresses.
Thanks.
Thanks.
Oops, didn't see you already posted.
http://www.transmissionpartsusa.com/700R4_2004R_transmission_parts_p/350-00035370a.htm
Here's a conical tv helper spring that can be bought without modifying one or buying a full kit. If you need a different plunger spring you can also find piles of them at your local trans shop, from all the 700r4 kits they've installed over the years.
Hope it helps someone
Here's a conical tv helper spring that can be bought without modifying one or buying a full kit. If you need a different plunger spring you can also find piles of them at your local trans shop, from all the 700r4 kits they've installed over the years.
Hope it helps someone
RmvBfrFlght
Well-Known Member
- Joined
- Sep 28, 2007
I know what you mean, it took a while for me to figure this out. It finally sunk in one day while staring at the above TV line up diagram. I left the Trans Go shim out of the plunger spring. But thinking about it I can see how it can be useful.
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RmvBfrFlght
Well-Known Member
- Joined
- Sep 28, 2007
The plunger/bushing combo handles part throttle (4-3) and detent (WOT, all) downshifts. Not all combos have the part throttle 4-3 circuit. In that case a detent 4-3 or 4-2 can take place.
For the high line pressure at idle, it is likely that the long plunger spring was mostly responsible for it. Without matching heavier TV valve springs the port was partly uncovered, causing higher then normal line pressure.
I had the same issue, 107 psi line pressure at idle at 1100 RPM in D4. And this was with the TV cable backed out. The plunger spring was most likely from a carb application at 2.165" long. This trans has a AA tag (Caddy) on the tail housing with a BQ3 VB ('84-'85 TB), so who knows what parts were in it.
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For the high line pressure at idle, it is likely that the long plunger spring was mostly responsible for it. Without matching heavier TV valve springs the port was partly uncovered, causing higher then normal line pressure.
I had the same issue, 107 psi line pressure at idle at 1100 RPM in D4. And this was with the TV cable backed out. The plunger spring was most likely from a carb application at 2.165" long. This trans has a AA tag (Caddy) on the tail housing with a BQ3 VB ('84-'85 TB), so who knows what parts were in it.
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TexasT
Texas, Where are you from
- Joined
- Sep 10, 2002
Not sure so much on the design but there are different diameter sets. I believe the largest is .430 and there is a .390. I didn't think to measure the one in my AA vb. I'm guessing the larger makes thinks happen faster but I'm not sure.
I do think that the high tv pressures that don't let it return to first can many times be attributed to a sticky valve and/or debris in the newly assembled trans. I know mine took a bit to get her shifting as I wanted. We drove it and disconnected the tv cable at the tb and gave it some sharp pulls with it running to clear it.
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TexasT
Texas, Where are you from
- Joined
- Sep 10, 2002
http://extremeautomatics.com/assets/pdf/2004R_Transmission_Install.pdf
This pdf has some pretty good pix and commentary on tv setup.
This pdf has some pretty good pix and commentary on tv setup.
RmvBfrFlght
Well-Known Member
- Joined
- Sep 28, 2007
To a point. Need to check the plunger idle length on your transmission. I also wonder where the images come from as they are also used (and more) on the Bowtie site:
http://www.tvmadeez.com/article/
If you can handle reading the multiple fonts, colors, and rants the bowtie site really does explain it well. Note that there are 3 pages on TV info there.
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