Question about the quirkyness of the AOD [Archive]

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dodgestang

07-25-2006, 08:23 AM

First off....I just need to thank Joe again for a great motor...it hit 7500 so freaking fast merging this morning onto route 30 that I had to go straight to OD and stand on the brakes to avoid running into the echo who was at 70 in the left lane when I start on the ramp. :-D

Anyway....

So....when I am driving in OD....and I downshift (manually) to 3rd...there is a short lag.
When I am in 3rd and I downshift into 2nd, no lag...BAM straight into second gear.

Its always been like that (as far as I know anyway). However with the new motor combo since I make power a little higher in the RPM band I find myself wanted to downshift into 3rd a lot more since I am ussually at 2200-2500 RPM in OD and want to get a little extra kick when I pass (sometimes anyway). It just seems a little weird to have to let of gas, downshift, wait 1 second, floor it.

I suppose I could just floor it and just wait for the kickdown.....but with the old motor, when I floored in OD the car just accelerated in OD by the time the tranny had decided it would be nice to downshift and help the pass, I was already done and at 100 MPH thinking I should slow down ;)

on edit: for reference it is an AOD with 4r70w gearset, one peice input, 3k stall, stock valve body and I think a B&M shift kit.

SilverFox

07-25-2006, 08:44 AM

The 3-4 and 4-3 downshift is tricky. Your complaint is universal, however there are some tips and tricks you can do to ease this problem.

4-3 the OD band must release and the Forward must apply. Your shift kit probably does not exhaust the OD preasure quickly enough or apply the forward fast enough.

Adjusting this shit is tricky as letting the OD go to fast and the forward not come on fast enough you get flare, that slips the Fwd clutches and eventually roasts them.....inversly, if you apply the FWD before the OD is release, you get a bind action that makes for a double clunk downshift and burnt bands.

I have been experimenting with this shift for years, and still not perfected it...and most kits don't do a very good job adjusting it...Baumann seems to work best...I would assume B&M kit being junk that it is, would not address the problem well.

RdRunnr

07-25-2006, 10:35 AM

dodgestang

07-25-2006, 10:38 AM

Have you thought about switching to a Lentech street terminator valve body? You would love it, and it would accomplish exactly you want. It has a toggle switch for OD and as soon as you turn it off, it kicks down and it instantly shifts down from 3-2 when you shift the lever.

I would like something to help me improve my response time from 4 to 3. The 3 to 2 shift will break your neck in my car if you are not braced for it and I am happy with that response.

SilverFox

07-25-2006, 10:54 AM

SOunds like you need to enlarge the Forward apply orfice so the shift is firmer - or next time you are inside the trans install a 4R75W truck wave plate in the forward drum to accelerate engagment pressure to the cltuches. Or toss the wave out - however this will produce pretty harsh downshifts and clunks into Drive position.

If you want to mess with the VB calibration I can provide you with the hole location to increase diameter for experimental use. Combining shift mods with :other": shift kits is always experimental.

dodgestang

07-25-2006, 11:55 AM

I don't open the tranny ;)

Too many little parts for to loose.

I tried replacing a bad governer valve once and it just got ugly and I ended with a completely fried unit shortly there after. So I may have to think about either 1. changing my driving habit or 2. finding a competant shop to to the tranny work (locally) ;)

RdRunnr

07-25-2006, 11:59 AM

Deltrans (http://www.deltransinc.com/) is right down the street from ACA on Old Baltimore Pike, and they are awesome. They freshened up my AOD and installed my current valve body for me. It's held up like a champ ever since.