J30 2-3 shift on very slow and feels like engine cuts off

[rwhyde]

I got my basketcase J30 engine going after the left camshaft seized and bent several valves, so on to the next problem. The transmission feel only OK wne accelerating very lightly but if I go to even alf throttle, it just bogs down like the engine turns off until I let up on the accelerator and the shift takes place. Engine runs really well so I'm not believing it is an engien problem but the trans computer telling the engine to cut off until the shift completes. I see several postings on different items. I'm curious about the 2-3 accumulator o-ring job that GQ Jay did but don't see confirmation that it fixed his problem. I'm also not sure his problem matches mine. My car is a '93 with 126K miles.

[elwesso]

Very common problem as the Q45 and J30 have the same-ish transmission (they are similar but arent technically the same)...

Could be due to shift solenoids wearing out!

[3Q Jay]

it just bogs down like the engine turns off until I let up on the accelerator and the shift takes place. Engine runs really well so I'm not believing it is an engien problem but the trans computer telling the engine to cut off until the shift completes. I see several postings on different items. I'm curious about the 2-3 accumulator o-ring job that GQ Jay did but don't see confirmation that it fixed his problem. I'm also not sure his problem matches mine. My car is a '93 with 126K miles.

first, i don't recommend messing with the accumulator. misguided attempt on my part (but you will learn how to handle the valve body!). If i ever did anything there again, it would be to put in a stiffer return spring on that piston--but again-best to find the real problem.

second, from your description--not clear. is there a loss of power, or do the revs just stop going up, until the shift finally completes? a smooth 'loss' of power may be the ecu retarding the timing.

how does your trans fluid look and smell? you have done a pan drop, magent clean and screen replace?

[rwhyde]

GQ Jay,

Thanks for the reply. I haven't done a pan drop at this point and the fluid looks and smells quite good. I was researching and came across your notes so was hoping you had a solution. I have the FSM and the best description in there is that it actually engine brakes the car on the shift. It just falls flat on it's face and actually decellerates. I can understand that often the transmission control units cut power to make sure the shift has time to complete so it is waiting for a signal back from the transmission that it has finished and to reapply power. This occurs so quickly in perfect operation that nothing is noticed. In this case the shift is just not completing quickly enough and it feels as if the engine turned off. When I let up on the accelerator everything resumes as normal and the shift completes. If I do not accelerate quickly (beyond just normal traffic pace) then everything seems to work OK. I can just go to dropping the pan and changing the fluid and filter and see what happens. The only item to check according to the FSM is the fluid level-done that. Perhaps the filter is so clogged up that insufficient fluid is reaching the pump. I've just never seen that before on any car. Could happen though. I'm kind of lazy and wold prefer to only do this job once so was inquiring as to any other known fixes while I was in there. thanks again.

[rwhyde]

OK, I'll check the solenoids according to the FSM and see what I find out. Any idea on cost, it is a 3 pack I think from the pictures.

Thanks

[3Q Jay]

while you are in the fsm, see if the J has a dropping resistor across the line pressure solenoid. check the thread on the -01a [yours] vs. -03a [Q45] valve body if you have not.

solenoids can be found on inet: try bulkpart.comremember, yours is the re4r01a.

[metaverse3]

Look at the TSB's here: zerothread?id=113076

Check the one for the shift shock. The ground wire is critical..

[rwhyde]

OK,

I ordered the solenoids, a filter and gasket, so I'll replace those and see what I get. I'll post my results. It was good to see bulkpart.com is in Dallas and I'm in a suburb, I should have my parts by next weekend and hopefully it will cure my ills. thanks for the advice.

[rwhyde]

Well, I fixed it. Bought the solenoids and have a new set if anyone needs some. I didn't install them. I did a scope of my throttle position switch but that was OK. It lind of felt like a signal dropped out and the car seemed to stall. I then broke down and checked my ignition timing. It was 8 degrees instead of 15 degrees and the car runs remarkably better now. I could learn to love this old dog. Apparently the engine and transmission control units conspire in ways I never imagined. I knew they talked just didn't think this could impact shifting so much. Just goes to show once again, get the basics right first.

[3Q Jay]

glad its improved. if you are going to keep the car, I'd make the investment in a full pan drop/new screen /magnet wipe--and add an external cooler, and perhaps a magnafine filter. Both the -03a and the -01a ARE underdesigned for their Q and J applications. That said, will bulk part let you return the solenoids? if so, but they want a restock fee--let me know. I'll match their refund offer.

side note--some have posted recently about an adjustment on the line pressure solenoid. did the one you received have an adjustment screw?