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Truck is an '83 with the 6.9. Truck shifts nice and firm under hard acceleration, but it won't shift until the same speed regardless of throttle application. it shifts into 2nd at the same 27 mph if I'm half throttle or full throttle and it refuses ti shift until that speed is reached. same with the 2/3 shift.
Now I'll admit im new to these old trucks but my understanding is that it should shift at lower speeds with lower throttle application just like any other automatic correct?
Where do I look for the problem, to get this thing shifting right?
You could try adjusting your VRV on the side of your IP. It rotates front or back once you loosen the side screws.
If that doesn't help, then you might need to adjust the top diaphragm by spinning the castle nut.
NOTE! Do NOT break this valve. Ford and all aftermarket parts companies has discontinued the C6 VRV. So if you break it, you are SOL. I have been working on making a VRV replacement on my website but due to plastics limitations, my progress has been slow.
first thing i would do is measure vacuum. 99 % of trans shifting issues are caused by a dying vacuum pump. you need around 19 inches vacuum for the trans to shift properly.
also make sure the downshift linkage is free and working properly. if the downshift linkage is stiff and stuck towards downshift, it will hold lower gear until almost 3000 rpm.
i always forget. Basically, I turn it ahead a few millimeters, then take it for a spin. IF it's still too early, then I turn it the other way. You'll see once you start turning it. It is pretty easy to adjust.
If your VRV is mounted with allen wrench holes, it's really easy to manipulate. But if you have the phillips screws, it's a PITA.
If you turn it all the way (in the direction you need) and it doesn't have enough room, then you need to turn the top castle nut. That pulls the diaphragm. it's more problematic to manipulate, because if you break the diaphragm or castle nut, you are SOL. There are NO replacements. I have been making replacements but I'm not completely done yet. Basically, I have been working building up an inventory of VRV parts (like a new cam link or castle nut), but I still don't have a viable diaphragm yet. Maybe in a month or so.
Here's the relationship of the castle nut with the diaphragm nozzle cap:
When you turn the castle nut, it pulls the camlink up or down. This is very delicate. I wouldn't recommend modifying it, unless you are sure that your IP rotation is completely out of spec.
So hopefully, you just need to rotate the VRV on the IP front or back a few millimeters. It's pretty easy to asjust.
i always forget. Basically, I turn it ahead a few millimeters, then take it for a spin. IF it's still too early, then I turn it the other way. You'll see once you start turning it. It is pretty easy to adjust.
If your VRV is mounted with allen wrench holes, it's really easy to manipulate. But if you have the phillips screws, it's a PITA.
If you turn it all the way (in the direction you need) and it doesn't have enough room, then you need to turn the top castle nut. That pulls the diaphragm. it's more problematic to manipulate, because if you break the diaphragm or castle nut, you are SOL. There are NO replacements. I have been making replacements but I'm not completely done yet. Basically, I have been working building up an inventory of VRV parts (like a new cam link or castle nut), but I still don't have a viable diaphragm yet. Maybe in a month or so.
Here's the relationship of the castle nut with the diaphragm nozzle cap:
When you turn the castle nut, it pulls the camlink up or down. This is very delicate. I wouldn't recommend modifying it, unless you are sure that your IP rotation is completely out of spec.
So hopefully, you just need to rotate the VRV on the IP front or back a few millimeters. It's pretty easy to asjust.
okay. So I’ve gotten it shifting through the gears at a decent interval, but still a bit too early... the castle nut however is pretty much unusable.. the case on this VRV has already been cracked and repaired at some point, so I don’t want to mess with it if I don’t have to... should I mess with the adjustment on the back of the transmission now to try and dial it in a little more?
Take that back. the VM on this ones transmission is not adjustable, so I guess i'm back to trying to "fix" the VRV in a way that has the diaphragm opened more... looks like the wire/spring that links the cam to the diaphragm has been stretched quite a bit when comparing it to the picture you have above, so im probably gonna have to redneck rig this one until you've got these new parts stocked up enough to sell.
okay. So I’ve gotten it shifting through the gears at a decent interval, but still a bit too early... the castle nut however is pretty much unusable.. the case on this VRV has already been cracked and repaired at some point, so I don’t want to mess with it if I don’t have to... should I mess with the adjustment on the back of the transmission now to try and dial it in a little more?
Can you post a pic of your repaired VRV?
Maybe I have some prototypes that you could use to replace your broken parts?
Maybe I have some prototypes that you could use to replace your broken parts?
the outer case is cracked in many places.. the internals seem to work okay, but the wire was stretched out at some point.. main issue I have is that the castle but is major stuck, and I can’t turn it back to lengthen the unit to compensate for the wire. I’ll try to get a picture today to post
If your VRV has already been repaired I would consider buying an adjustable vacuum modulator for the transmission. They aren't that expensive. Plus they are stupid easy to install and adjust.
FWIW, I have an adjustable green striped VM (you can also buy black as well as purple ones). I installed it in my truck when I adjusted the VRV. It works well.
If your VRV has already been repaired I would consider buying an adjustable vacuum modulator for the transmission. They aren't that expensive. Plus they are stupid easy to install and adjust.
FWIW, I have an adjustable green striped VM (you can also buy black as well as purple ones). I installed it in my truck when I adjusted the VRV. It works well.
are these parts interchangeable then? I was concerned I wouldn’t be able to get the new VM installed if I bought one... next issue with that is scraping through all the excess undercoating to find how to get the old VM off lol
The VM is at the back of the transmission with a vacuum hose going to it. It should be easy to remove. I think it's 1 or 2 bolts and it slides out of the transmission. Make sure you have a catch pan though, you'll loose some fluid when you pull it out.
I scoured the forums and never found a definitive answer as to what color VM is needed for our trucks. I read both green AND black are the diesel VMs. As I mentioned, I'm using a green one and it works great. Hopefully one of our experts will chime in and let us know which color is OE for the 6.9l IDI with a C6.
The VM is at the back of the transmission with a vacuum hose going to it. It should be easy to remove. I think it's 1 or 2 bolts and it slides out of the transmission. Make sure you have a catch pan though, you'll loose some fluid when you pull it out.
I scoured the forums and never found a definitive answer as to what color VM is needed for our trucks. I read both green AND black are the diesel VMs. As I mentioned, I'm using a green one and it works great. Hopefully one of our experts will chime in and let us know which color is OE for the 6.9l IDI with a C6.
is there much difference internally between the colors?
The VM is at the back of the transmission with a vacuum hose going to it. It should be easy to remove. I think it's 1 or 2 bolts and it slides out of the transmission. Make sure you have a catch pan though, you'll loose some fluid when you pull it out.
I scoured the forums and never found a definitive answer as to what color VM is needed for our trucks. I read both green AND black are the diesel VMs. As I mentioned, I'm using a green one and it works great. Hopefully one of our experts will chime in and let us know which color is OE for the 6.9l IDI with a C6.
Quote from a manufacturer of the VM’s
”The black stripe is a small diaphragm/low vacuum modulator and is mainly used in heavier vehicles and trucks. It has a low shift point. This modulator is also popular in performance applications due to the low shift point.
The purple stripe has a slightly larger diaphragm and is designed for use in normal to heavier passenger vehicles. It has a medium shift point.
The green stripe is similar to the purple stripe, but will provide a slightly later shift point. It is designed for normal passenger vehicle usage and is the most popular modulator used the C6.
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