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General TR Overdrive Pressure Test

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KVH

KVH

Obi Wan
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I'm getting 370 for pressure, but I have another question. Maybe really dumb. Do I need to remove the steel ball in the valve seat? Also, I spin counterclockwise so that the front spins clockwise, like the engine, correct?. Finally, is my pressure and speed supposed to drop when I engage the OD solenoid? I'm not noticing any change at all.
 
If you are using the adapter plug, then leave the ball in place while testing. 370 sounds in the ball park...but let me read again to make sure (It’s been a while). Yes, if you are spinning the tail shaft (and you are spinning it the correct direction) and then engage, the input shaft should slow...but it is not a large difference visually. You should be able to hear the drum engaging the shoe, and you will see at least a slight drop in pressure which will come back up quickly.

The release from OD is normally pretty slow with no load, taking several seconds.

To check if the OD is engaged, stop the power spin and then attempt to turn the tailshaft clockwise (reverse). If it locks and will not turn, then it is engaged. The OD will remain engaged for several minutes at least, even after the shaft stops spinning.
 
OK, just read the manual, and, depending on which model you have, I think about 410-430 psi is recommended for the later model...and 370 is about right for the early model. The adjustment for pressure to to shim the large accumulator spring about 1/16” for every 32psi needed. So in your case about 1/16 to 1/8” shim should do it.
 
You know, now I'm confused. I just ran my electric motor setup again and when I engage the solenoid/overdrive the pulley speed actually increases and the pressure seems to remain constant. Is something wrong?
 
If you're driving the Trans/OD from the output flange, it makes sense that the pulley speed would increase when OD is engaged. Your electric motor may not be strong enough to spin the transmission very fast when it's in direct drive, but when OD is engaged it gets a better mechanical advantage and can spin the output shaft faster for the same mainshaft speed in the transmission.
 
I just re-read your post. I assumed you were spinning the tailshaft, but I see now your didn't actually say...so how are you spinning the unit?

Also, again, regardless of what you are seeing, if you cannot tell for sure, then stop the power spin with the solenoid still energized. Then attempt to hand spin the tailshaft clockwise. If it locks up, then you are engaging. If it is not locked up, then you are not getting OD.
 
Cool idea, Tush. I have one of those from my RC flying hobby...but never occurred to me it would work with cars too!
 
I'm spinning it from the rear, the output shaft. I'm pretty sure that when I engage the OD, the output shaft is spinning a little faster. But I'll do as suggested, and cut the power with OD still engaged and see if it's locked up as suggested should be the case. I'll report back. thx
 
philstr6 said:
whats the number on the brass plate on the overdrive to get you the correct pressure
Phil
Click to expand...

22/1374 16198

I think that's consistent with the lower pressure. I'm seeing right about 350-355.

With the OD engaged my speed is greater, and if I shut down with OD engaged, I cannot turn the tail output flange clockwise (facing the rear of the transmission).

Am I ready to put this beast back in my car. Please!!
 
your pressure is correct and good for the overdrive 22-1374, when you test and your pressure is at 350,when you shift it in to overdrive the pressure should drop 50 lbs and then come right back to 350,
when you release it out of overdrive,your flange on the rear should spin both ways free,if it doesnt you are stuck in overdrive.No you should not put it in yet, you can tap on the back of the overdrive to release it,or the operating valve is clogged,very small pin hole that is plugged and wont release the pressure,have to take it out,easy while on the bench,take your gauge out,ball spring plunger as well,and then take a magnet and pull the operating valve out and ck the pin hole in it,blow into the valve,you will know if its plugged,the put it back in and retest
Phil
 
That would be my guess too. If you see no pressure drop, then there is a good chance the box is staying in OD. De-energize the solenoid (tailshaft spinning or not), and see if it drops out by your being able to spin the tailshaft clockwise.

If it is coming out of OD, then you are good to install. If it is not, then either the ring is sticking in the drum, or the valve/solenoid needs to be adjusted.
 
Everything seems be working perfectly including the disengagement of the overdrive after I turn it off. In other words, the tail shaft will rotate clockwise from the rear. When it is locked, it will not rotate clockwise. Pressure builds up to 350 and the overdrive seems to be engaging perfectly. The only thing that makes no sense is that I am not seeing any pressure to drop whatsoever when I engage overdrive
 
Well, not sure. I pulled and cleaned that operating valve pinhole. It actually was a "bit" blocked. I sprayed some cleaner into it and blew out the sludge. Much better air flow. Pressure, however, only seemed to drop about 10 pounds so I made a huge life decision and slammed that transmission back in the car and I plan to be back on the road by next weekend. For me, putting the interior back together is a two day project--center console, all the impossible bolts on the hump, retacking carpet, that center saddle and dash support (2 hours), the glove box, the radio and the aching back. But I'll get there. Good thing I'm not a mechanic charging hourly for my repair antics.
 
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