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TH2004R on my 1984 Delta88 will not shift into 2nd
Long story short:
TH2004R on my 1984 Delta88 will not shift into 2nd. 120k mls and I guess it is the first transmission. 307 engine.
Started out with shift issues (hard and late shifts) after the car was not moved for a while. Thought might be the TV cable that was slightly stuck. After driving it more often problem did not reappear
Until one day: It did not shift out of 2nd (not 100% sure, but I recognized something wrong after a stopped and wanted to accelerate). Downshifted manually to 1st and then back to D. Since then no up-shifts to second, so I stopped at the next parking lot and saw some drips of transmission fluid. Fluid was a quite low, so I topped up half a liter.
Tried to drive again, but still no up-shifts. So I parked and realized quite a puddle of ATF fluid underneath my car. Car was towed home.
Removed pan:
- ATF fluid was cherry red, smelling normal, not burned
- TV Valve was moving smoothly
- Very little particles in the pan and in the filter (I even opened the filter). Only one small white/yellowish plastic debris found.
- Removed gearbox to change both shaft seals
- Renewed all sealings for hoses and connectors
- Installed new filter and new transmission sealing, new TV cable and reassembled everything
- (Short Comment: I had no clue what I was doing 😉 So I forgot to check the governor.)
- Refilled new fluid, still no upshifts until 50mph.
- 1st and reverse engage smoothly, I think OD also causes slightly changed rpm, but not sure.
- Still very little leakage of ATF in between transmission and engine.
- Measured inline pressure, RPM was at idle, engine warm. Pressure did not change at higher revs. First value is TV cable low, second is TV cable max:
Redid this measurement another day, got slightly higher values (+20-30psi).
I know how to wrench and work on cars. I have access to a hoist. But I have no clue how to diagnose an “older” automatic transmission. Could some point me into a direction where and how to look.
Side mentioning: I also have electrical troubles. Rear turn indicators light up every time I press the break. It is not rear lamp nor brake switch related. Had no time (and no clue how to :-/) to fix it. Could this influence my trans somehow?
Last edited by 1984_Delta88; January 20th, 2022 at 02:39 AM.
Check the governor, it will not shift out of first if somehow you lost a spring/check ball. I had it happen on my 88 CSC. The only electrical on a TH2004R is the lock up torque converter. Which either sticks on a causes a motor to stall or buck at a stop or not work at all. Good luck.
Last edited by olds 307 and 403; January 20th, 2022 at 07:33 AM.
Guess I saw your rebuild thread which is really detailed and helps with any work on the transmission.
Yea, my bad not to check the governor when I had the pan removed. I just thought it might be linked somehow to the leakage, I will try to get a new sealing (here in germany) and check the governor. I will give feedback in this thread... thanks for your advise.
It’s been a long time since I messed with a 2004R, so my memory is a bit fuzzy.
If the car still runs (meaning you haven’t removed the pan) do the line pressure test with the tires off the ground and free to turn. Slowly accelerate thru the gears, if you look closely at the gauge you should see a very quick dip in line pressure on every gear change. If you see a drop on the 1-2 shift, and then the pressure immediately recovers, then you can be reasonably sure that hydraulically the trans is making a 1-2 shift, and the problem is mechanical.
The forward clutch is applied on every forward gear, the low roller clutch is locked anytime the car is moving forward. To get second gear, the band comes on. Third gear the band releases, the 3rd clutch comes on. If you have first and third, then the band or whatever applies it is suspect.
If I recall, there is a exhaust hole on the pan rail below the servo. Apply air to that port and see if the band applies. Hopefully you can see it up thru the case. It’s possible either the band anchor tip sheared off, or the welds that hold the apply lug to the band broke. If the servo applies, and you can’t see the band apply around the drum with a good solid thud, then it’s time to drop the valve body. Pull the band anchor, see if the tip is broken. This will also give you an opportunity to inspect the 1-2 accumulator and the shift valves.
If the car still runs (meaning you haven’t removed the pan) do the line pressure test with the tires off the ground and free to turn. Slowly accelerate thru the gears, if you look closely at the gauge you should see a very quick dip in line pressure on every gear change. If you see a drop on the 1-2 shift, and then the pressure immediately recovers, then you can be reasonably sure that hydraulically the trans is making a 1-2 shift, and the problem is mechanical.
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Tried this, but there is no "shift" even with wheels off the ground. So this would also be "+1 for the governor" (or any other hydraulic issue)? I read a lot about broken governors lately. So i really hope that'll be a quick fix.
Short feedback: Everything works as intended again! Root cause: stupidity I guess.
I had the chance to drop the pan yesterday and took a look at the governor. But it looked pretty intact. Springs, weights and gearing looked OK.
This confused me.
Looking at the TV valve again I realized the lever was not touching the TV plunger. To be honest it was not even close :-o (picture shows lever after final adjustment)
So I took a look at the (freshly installed brand new) TV cable. As I was not able to get a OEM part I had to use one of those universal things that uses a… “screw thing” (see picture below – I don’t even know the german name for this). And, I assume, after adjustment I did not properly tighten the screw last time During the first road test when I accelerated it probably moved.
Now, after reassembly and correct adjustment I had my olds shifting through the gears smoother than ever 😊 At least first to second and back. I need to take it for a longer drive next days.
Does this make any sense? Would a loose cable lead to not shifting into 2nd? Just glad it did not completely cook my tranny :-/
BTW.
Still not sure, how to adjust it properly. I mean the procedure by the book is clear. But is there a better way?
The first time I measured my original cable an put it at the approx. same position and then let it self adjust.
This time I shortened it until the lever was touching the plunger in the trans (pan was still open so I could see it).
Or should it already operate the valve plunger at idle?
Should there be a certain gap between lever and CV?
Is the TV plunger being totally depressed into the TV bushing at WOT?
What would be the optimal position?
Last edited by 1984_Delta88; January 28th, 2022 at 06:22 AM.
That adjustable cable sounds like a good idea. If shorten slightly, the very rapid upshifting, that was built in the design, could be delayed to aid drivability. If the cable is disconnected, wouldn't that cause premature upshifting rather than no upshifts? Who is the trans expert?
If the cable is disconnected, wouldn't that cause premature upshifting rather than no upshifts? Who is the trans expert?
That was also my understanding from what I read on the forums. But currently i do not have another explanation :-/ I will see how the proper test drive will end.
.Yeah, the governor looks fine. Hopefully you checked the Servo pin etc Matt69 mentioned. It does cause early upshifts, one almost on top of each other. I learned that from a Dualjet that would have been in front of a TH200 does not use the same TV bracket as the TH2004R attached in the same position on the intake.
January 20th, 2022, 02:35 AM
During the first road test when I accelerated it probably moved.
