Vacuum pump/late shifting M1009

[DREDnot]

Been searching the archives all weekend.
My M1009 has the standard issue late/hard shifts.

Per forum advice, Replaced all (dry rotted,but not obviously leaking)vacuum tubing.
Replaced the vacuum modulator on the trans with a NOS ACdelco part. Vacuum Tubes on proper ports. Lower to pump, upper to trans.
Replaced trans filter(ACdelco) and oil. O-ring and pipe installed properly. No more leaking trans pan gasket, which is nice.
Replaced Vacuum Regulator Valve with a NOS military part. Tried about five different clocking adjustments with minimal changes.

I did not check the trans governor.

At the start, the first thing I did was put my vacuum gauge on the vacuum pump. It would rapidly oscillate between 0 and 18+ with each stroke of the diaphragm. It would not hold vacuum.

I searched but have not found any discussion about if this is normal, or a sign that the vacuum pump is kaput. I found an item yesterday in the -34 TM about holding vacuum for a time after engine shutdown, which my pump wont do.

I figured "What the ****" might as well throw a new pump in there as well....Solar system wide backorder or discontinued. This is for the ~$100 units. Not ready to drop a quarter grand on the ONE unit on ebay. All my parts houses in phoenix are backordered indefinitely, except for one oreilleys that can have one (new borg warner?) tomorrow for $285

I pulled my pump out this morning to see what's up with it. Maybe a check valve that was sticking for an easy fix. Ive unbolted the diaphragm to find normal looking operation(cam and pushrod). Haven't tried unscrewing the pushrod nut to see what's underneath it yet.

Are these things supposed to hold steady vacuum, or just a rapidly oscillating reading like I was getting?

Anybody got a source for these that don't cost an eighth of the purchase price of the vehicle?

 

[cucvrus]

When you have the pump in place with the engine running does it suck your finger tip fast to the fitting or a hose attached to the fitting? It will make a chirping sound and should have good suction at idle. I am checking a NAPA price. I bought one a few years back. About $125. I think. Wrong answer $248. at Autozone for a new one.
http://www.autozone.com/engine-mana...cuum-pump/453114_0_30433?&searchText=nlvp1697

 

[cucvrus]

Rick,
Part Number 2-29829 price is 167.89
This was NAPA's reply. I am a whole sale buyer. Your price may vary. Hope it helps. Good Luck.

 

[DREDnot]

When you have the pump in place with the engine running does it suck your finger tip fast to the fitting or a hose attached to the fitting? It will make a chirping sound and should have good suction at idle.

I didn't put my finger to it. I attached my vacuum gauge. The needle oscillated rapidly and completely with each stroke of the diaphragm. No steady reading whatsoever. Each stroke got a full needle sweep.

https://www.youtube.com/watch?v=geBJdWYXaCI

 

[cucvrus]

Try your finger on. I have mine off and it sucks the finger tip fast. I will hook up my vacuum if I need to to help you out. I can't film. I don't know how. Really.

 

[DREDnot]

I have the pump removed at the moment. Checking it for any obvious damage/malfunctions.
If you could hook up a vacuum gauge and see if you get the same result mine has, that would help to determine if mine is normal, or not.

 

[Bighorn]

I have the pump removed at the moment. Checking it for any obvious damage/malfunctions.
If you could hook up a vacuum gauge and see if you get the same result mine has, that would help to determine if mine is normal, or not.

When you get your vacuum pump sorted out, adjust the transmission vacuum modulator.
Pull the vacuum line off the modulator on the trans and using a tiny flat head screw driver, turn the screw inside the open vacuum fitting counter clockwise to lower/soften shift points and clockwise to firm up, raise shift points.
Maybe you knew about that screw inside the vacuum port of the modulator.
If so, sorry.
A warning; You don't want the transmission to shift too softly.
The softer it shifts, the more wear on the internal friction discs.
Firmer is better.. within reason.

 

[sneekyeye]

I just ran this test yesterday on my m1028. I got a solid 24 pounds of vacuum at idle with no fluctuation or bouncing. I'm in the opposite camp as you. I don't have a vacuum regulator on my injection pump, so my trans gets full vacuum all the time, and shifts way early and soft.

In addition, my vacuum modulator on the turbo400 doesn't have a screw in it. The vacuum is adjusted by the regulator on the side of the injection pump. I understand the factory modulator on the trans did not have a screw since it was adjusted by turning the regulator in the injection pump.

 

[Bighorn]

I just ran this test yesterday on my m1028. I got a solid 24 pounds of vacuum at idle with no fluctuation or bouncing. I'm in the opposite camp as you. I don't have a vacuum regulator on my injection pump, so my trans gets full vacuum all the time, and shifts way early and soft.

In addition, my vacuum modulator on the turbo400 doesn't have a screw in it. The vacuum is adjusted by the regulator on the side of the injection pump. I understand the factory modulator on the trans did not have a screw since it was adjusted by turning the regulator in the injection pump.

I guess the previous owner added an adjustable vacuum modulator to mine.
In fact, every Turbo 400 I have every run across had an adjustable modulator.
Maybe it's one of those things everyone just does to their rig when the stock mod. goes out.
Seems unnecessary since vacuum is already modulated at the injection pump by throttle inputs.

 

[DREDnot]

I guess the previous owner added an adjustable vacuum modulator to mine.
In fact, every Turbo 400 I have every run across had an adjustable modulator.
Maybe it's one of those things everyone just does to their rig when the stock mod. goes out.
Seems unnecessary since vacuum is already modulated at the injection pump by throttle inputs.

Yeah, i checked for the adjuster screw inside the modulator port before I installed it. None on this one.

Its good to know that the pump should be providing steady vacuum. That makes sense as the choppy vacuum cant be very useful.

Sent from my SM-N910P using Tapatalk

 

[Sharecropper]

I believe I may have a brand new NOS 6.2 vacume pump in my parts bin. I will check tomorrow and let you know. If so, I am open to a reasonable offer.

 

[DREDnot]

Cool. Let me know.

Sent from my SM-N910P using Tapatalk

 

[milradioman]

My son's M1009 has the same problem; transmission not shifting right, oscillating vacuum on the vacuum pump, when I tested it the vacuum oscillated from about 8 to 24 psi of vacuum.
I don't remember seeing this on my other cucv engines.
I started looking at sourcing replacement pumps, but I also found no stock, except for ebay at what seams like a high price.
I have a vacuum pump I pulled from a parts vehicle, it tested worse; oscillating but only 5 to 10 psi, so I ground off the crimp on the diaphragm unit, to see what is inside, cleaned the oil out of it, and that is as far as I have looked into it, I suspect the diaphragm is good on my son's unit, it is probably a bad valve, I plan to check and see if there is an easy way to rebuild it.
I have found a number of sources for the 6.5 engine vacuum pump at a reasonable price, has anybody checked to see if the diaphragm unit would bolt onto the 6.2 pump?

 

[Bighorn]

If all the engine mounted vacuum pump is doing is supplying a constant vacuum that is modulated by the regulator on the injection pump, I wonder if it could be replaced with one of these?
https://www.summitracing.com/parts/...5Hvt7ccjHsCROc1mQmi4GWZYSOUjN3bhoCqSQQAvD_BwE
-Cheaper than a replacement pump.
-Leave the non functioning or low function engine mounted vacuum pump in place perhaps until a replacement is found.
-restores function of smooth transmission shifting.

I haven't looked into to it yet, but if vacuum pump output is supposed to just be the supply and the regulator does all the work to make that into signal for the transmission mounted regulator, then this approach could work.
OR Does the engine speed influence the engine mounted vacuum pump output and play a part in the regulation along with the injection pump regulator?
That would be a flaw in my plan.

 

[Sharecropper]

Cool. Let me know.

Sent from my SM-N910P using Tapatalk

I was wrong. The pump I have is my original vacuum pump which I exchanged with the NOS pump. There was nothing wrong with my original pump, I simply had the NOS pump and swapped it when I did my injection pump rebuild. The original pump only has approximately 13,000 miles on it. You are welcome to it for a nominal fee plus the cost of shipping. Let me know.

 

[sneekyeye]

That hella pump on summit keeps a steady 15 pounds of vacuum. A good original keeps 24, so there would probably have to be adjustment done to the regulator and/or modulator if someone were to put one in in place of the original vacuum pump.

 

[Bighorn]

Summit has a vacuum pump direct replacement for the 6.2 with federal emissions, in stock for $109.
Ditto, Advance Auto Parts has them too.

 

[DREDnot]

I have a vacuum pump I pulled from a parts vehicle, it tested worse; oscillating but only 5 to 10 psi, so I ground off the crimp on the diaphragm unit, to see what is inside, cleaned the oil out of it, and that is as far as I have looked into it, I suspect the diaphragm is good on my son's unit, it is probably a bad valve

Do you have any pics of the inside? I like to "autopsy" my old components to see how they function. I don't want to cut mine open yet, but I'm curious as to what the valves inside look like. I'm wondering if they are just stuck preventing it from holding steady vacuum. Maybe something just a small amount of oil, or wd40, could free up? This seems to be a common ailment and it would be nice to find a possible simple cheap fix/work around.

 

[DREDnot]

Summit has a vacuum pump direct replacement for the 6.2 with federal emissions, in stock for $109.
Ditto, Advance Auto Parts has them too.

Thanks for the info
Just called on both.
Despite what their website shows, summit is out of stock. Estimated restock shows 10/23 but they cant confirm that even.
Advanced doesn't actually have any either. Just the borg warner unit in their ABQ warehouse @$260

 

[Bighorn]

Sorry.
Just to confrim, checked my vacuum on my M1009 just now; 20 " at idle fairly steady 25 degrees outside cold start.