Mrvedit.....1 thing i was wondering about when pulling the plug and putting it in limp mode was, when in limp mode does it use the OR clutch or is it just 3rd. The reason i'm asking is because it works fine when i shift manually but the OR clutch engages on manual gear selection so my 3rd clutch is using the OR as a crutch. if limp mode engages the OR then it wont really tell me anything

 

Look at the GM table I just posted as #33 in this thread:
https://ls1tech.com/forums/automatic...seccond-2.html

I would need to study the hydraulics, but a quick guess, the overrun clutch might depend upon the position of the shifter, as in that table.
So off in [OD], but on in [D3]. But just a guess.

BTW - There are 3 very similar threads going on now and I'm trying not to get them confused.

 

Yes i saw the table. Iv'e been following that thread too.that makes sense about the OR clutch being dependent on shift lever position. So if i just unplug it and run it in D4, it sHould be in normal 3rd gear limp mode w/o the OR. I'm going to try it tonight before i pull the trans back out.

 

Great that you are following the other similar threads.
I posted the GM tech manual's table because the ATSG manual's table has a mistake in it related to the OR clutch. The ATSG manuals shows the OR clutch engaged in 1st and 2nd gear with the shifter in [D3], but they are not. In [D3] the OR clutch is only engaged in 3rd gear. Unless you have the Sonnax HD 2-3 shift valve installed, then the OD clutch is always engage in [D3].

 

Just out of curiosity, and i don't mean to come off looking like an idiot, but would it be obvious if the 3-4 clutches were bad ? I know burnt clutches would be obvious but what about just bad clutches ?

 

Clutches can also "cone", have the linings separate and various other problems.
I think a combination of a small leak combined with low line pressure is causing your issue.

 

Can you tell me where in the fluid flow path the pressure test port is ?...i'm just wondering if the leak isn't causing the low line pressure, which means i'd need to check before the pressure tap as well as the 3rd gear circuit.

 

Sorry, I don't quite understand.
The test port is on the driver's side of the trans. It's a pipe-thread plug. IIRC a 7/16" wrench/socket takes it off.

 

Sorry...no i mean is it testing straight off the pump or after it flows through the drum. Where in the flow path is the test port. I know where to tap into it. I tested it last night.

 

Ok i pulled the plug and its idling around 165psi. Just touching the throttle jumps it to 225. I drove it and it stayed up 225 and started dropping to 200 by about 50 mph and about 185 by 55 mph.

 

No ideas ?

 

Your pressure is high enough to prevent serious slippage.
Sorry, but it is looking more and more likely that there is a leak in your 3/4 clutch circuit.

I suppose you could perform a clutch test while the trans is still in the car by removing the valve body and replacing it with a test plate. I'm confident it would show a leak. But if you want to consider this, search ebay for "4L60E air test plate". It is $75. Since I am willing to "rent" it out to future members, I will buy it from you for $65 after you have used it. Just a "wild" idea, but other than removing and opening the trans, I currently have no others.

 

Well let me run this by you....i called transgo with my issue and in their opinion, its a computer issue, because when i pull the plug and put it in limp mode it runs 225 psi but when i reconnect the harness it wont run that high. They think the computer isn't commanding the right pressures through the force motor. This makes sense i think but my only reservation is that i'm not throwing any codes. I'm planning to get out my meter and run a check on the tps tonight.

 

Granted it should jump to 225 under moderate+ acceleration.
I only have to blip the throttle in Park to see 225.

You could try disconnecting the trans (3rd gear only) and take it for a test drive. Once up to reasonable speed (and safe area), go WOT and try to feel if the trans is slipping.

If it doesn't slip, an adjustment to the tune might solve the problem. Is this a stock tune? Nearly all tunes, stock or otherwise, specify very low current through the PCS at WOT.

Also, have you already tried the overfilling the trans by 1/2 quart?

Also, what size did you drill the 3rd feed hole? I still think you have at least a small leak, but a larger feed hole (up to .125") will help overcome that.

Based on reading your entire thread again, perhaps the best next step is getting your pressure up to 225psi when you blip the throttle in Park/Neutral. The PCS, the tune and even the PCM are all suspects.

 

Mrvedit, Ive been thinking about what you said and what others have said and i want to run something by you....if voltage to the pressure solenoid is controlled by throttle position, then it seems to me that i'd have an issue with all shifts not just 3rd gear....i.e.....if i take off from a dead stop, give it say 3/4 throttle and hold it there, wouldn't i have the same voltage to the pressure solenoid all the way through all shifts ?...if so, then i should have a problem with all shifts and not constantly just 1 specific gear change. This leads me to believe what you said about a leak, specifically in the 3rd gear circuit more so than a bad computer or tps....

 

Technically the Pressure Control Solenoid (PCS) is not controlled directly by the throttle position, but rather according to the calculated load on the engine and the tune. Obviously throttle position is part of the load calculation, but so it the MAF and MAP.

However, your idea is correct - the pressure should only depend upon the load and not which gear you are in. Have you tried driving and watching the pressure gauge?

 

Yes both normal and in limp mode. Under normal conditions the pressure at the 2-3 shift is only about 150 psi. In limp mode its up to about 225 until about a 50 mph steady speed where it starts dropping to about 200 and then to around 185- 190ish @ 55mph.

 

I am working on a 94 with tbi so i have no MAF.