3at auto shifts at 4000 rpm

[snowstormer]

ok hear me out before you say "governor"

 

still dinkin with the 83 coupe tranny.

 

will shift into all gears but not till you wind it up to 4000 rpms.

 

have tried 3 known good modulator valves and have tried adjusting them. have tried 2 known good governor assemblies that have worked fine in other transmissions. the gov that came out of the car was not apple cored or anything.

 

all govs and mods act the same... 4000 rpm shift point.

 

fluid is full and good.

 

am i missing something obvious here?

 

any replies are welcome. thank you.

[NorthWet]

Governor

 

OK, how about dirty valve body?

[ShawnW]

Clogged filter?

 

Is there more fluid in the differential than there should be...Ie...exchanging fluids?

 

Vac lines messed up so its not getting a vac signal at the right time so it doesnt know to shift?

 

Hey is that my old 83 GL 2wd coupe? The white one??

[snowstormer]

thanks for the suggestions northwet and Shawn- you just had to say guvner didnt ya?

 

 

yup- thats your old white coupe Shawn. funny how these rigs get around... kinda like some of your best friends girlfriends when i was a young lad.

 

she lives again. everything works, and ready to roll. except for the nagging tranny problem. i want to exhaust all the options before pulling it out and putting in a 5spd...

 

thanks for the replies.

[NorthWet]

Yup, I had to say it. Its been most of my 3AT problems... "When you have a hammer, everything looks like a nail."

 

Doubt if your 3AT has a filter. Mine don't, just a screen. After I cooked my fluid, I pulled of the valve body and found a lot of black particulates all through the valving.

 

Might also be pump pressure issues. Any difference hot or cold?

[Hondasucks]

your modulator valve inside the transmission could be stuck, take the modulator out, and use a magnet to retreive the valve from the valve body. Note which way it came out, it's gotta go back the same way! it should slide right out of the valve body, if it hangs up, there is your problem. If it slides out easily, slide it in and out of it's hole a few times and feel for sticky spots. Might be some varnish buildup on the valve, which can be removed with brake cleaner (Don't be tempted to use sandpaper to clean teh valve, if you absolutely MUST use something abrasive, use 2000 grit wet/dry paper with some ATF on it, and set the paper on a piece of glass, and lightly roll the valve between your fingers against the paper, don't rub side to side, roll it, or you will out-of-round the valve and have to replace the valve body.

 

 

Another option would be to obtain a pressure gauge, and attach it to the proper port on the transmission (I don't know which one, but you can get an ATSG book for it for about $15, the transmission is an M41) and monitor the modulator pressure, should be ~20-40 psi with full vacuum applied, and increase to 140 or so with no vacuum. If you can monitor the line pressure as well, it should rise with the modulator pressure, although it doesn't rise as much, maybe 20 PSI.

 

I don't have exact figures because I don't have an ATSG manual in front of me...

[JWX]

so it doesn't shift until 4k atleast.....and your complaning?

[snowstormer]

thanks for the suggestion hondasucks. i will try that on saturday. never thought of that.

 

yea jwx, 4000 rpm powershifts are fun, till the dang thing blows her cookies!