AOD Issues

bluebird

Registered User
Ok,

I was finally able to put a little time into working out some of the issues with my SC this weekend and I found that @ WOT my trans shifts way too soon and skips 2nd gear. The car will run to about 3500 Rpm and shift from 1st to 3rd. If I drive normally it shifts through all the gears fine (still a bit early though) I've checked my trans fluid and IMO it could use a change but its not bad at all. What are my options? Has anyone else had this problem? Oh yeah big props to bluecoupe 5 speed for the hookup on some tires this weekend!
 
From what I understand, the 1st to 3rd shifting is normal for our AOD's. If you install a shift kit (TransGo for example) the shift pattern can be changed to 1-2-3. As far as a fluid change, some folks say not to do it, others say its a must. I have always changed mine about every 60 to 70K miles. Not a difficult job, but it is messy. I figure that fresh fluid has got to be better than old stuff. Don't forget to drain the torque converter if you decide to service the tranny.
 
shifting

Is the shifting at 3500 normal too? Is 2nd gear only for cruising? I really hope that isnt right cuz I'm gonna be pretty P.Oed. Is there anyway to check to make sure that my trans is operating properly?
 
I'm not sure about the 3500rpm shift point...this could be the result of the TV cable being a little out of adjustment (the transmission shifts are controlled by the TV connection on the throttle body). Slight variances in TV adjustment change the hydraulic fluid pressure in the AOD. This can result in failure if not corrected. There is a simple procedure for setting the throttle valve, but some folks say it should be done with a guage to get it set properly.....
 
????? I've read that there are springs that may need changing. Anyone know what they are and how hard it is to do?
 
There are springs "loading" the servo's in the valvebody, but you would only need to change them if you discover they are broken while doing a rebuild or maybe when installing a shift kit.
 
Is a shift kit something that I can do myself or does it require some serious labor? I see a lot of posts about the Trans-go shift kit. Are there others that are comprable?
 
Well, the first thing would be to head over to the TCCOA site and check out the article on setting the TV cable. If it proves OK, or after adjustment the concern persists then there's two ways to go IMO.

One would be to go through and replace all springs in the valve body AND governor to ensure that they are indeed at spec. It's a huge hassle, both getting and getting to them. The governor, for instance, is inside the tailshaft housing so you have to pull the driveshaft, crossmember, and tailshaft housing off to access the governor. BTW the governor is one of the likelier candidates for the concern. If the springs are weak the counterweights will be able to overcome them quicker and move the slider valve sooner resulting in a premature upshift. You might have to try a few different combinations to get the WOT upshift speed you want.

The other way, which is much more common since it's far easier, is to reprogram the valve body to allow manual control of upshifts. The "shift kit" is usually a set of instructions to make some changes to some passages in the valve body separator plate (a plate that goes between the valve body and the trans body) along with perhaps a new spring or two, or the removal of a spring here and there. It just depends on the kit and what you're trying to do. A drill and an inch-pound torque wrench are necessary items. No cheating on the Valve body torque figures or pattern. I'm serious. Attention to detail will be needed also as there will be VERY specific locations to drill and place check balls. For a first time, budget a weekend.

I would like to suggest though, that if you choose the VB reprogram route then you consider just replacing the VB with a Lentech Street Terminator AOD VB. Very much more expensive ( $400) it offers at least one one thing that a simple shift kit does not. The ability to lock-out OD. This means no slugging along at 40mph in OD in traffic. Being able to hold OD off while jockeying for position on the on ramp (BTW AOD's should not be operated in D for very long as they under-oil the planets in that position and the word is that frequent manual lever movement while moving tends to result in decreased OD band life).
 
Parker Dean said:
Well, the first thing would be to head over to the TCCOA site and check out the article on setting the TV cable. If it proves OK, or after adjustment the concern persists then there's two ways to go IMO.


Eeek! Don't set it that way, get a pressure gauge and set it from the TV port on the transmission. I thought that I had it set right, or close to it, and then I put a gauge on it. I started the car up, and the gauge read ZERO. Zip, nothing, nada. I nearly **** myself when I saw that. It turned out that the TV cable had to be pulled out an additional 1/4 to 3/8 of an inch to get the correct 34 PSI, even though the cable was set to the TCCOAs instructions. The entire gauge apparatus can be purchased from Sears for under $20, which includes the gauge. You need to cobble together the fittings and such, but it is still very cheap.
 
I set my throttle pressure with a gauge as well. You'll need a block that is .215 thick. I made mine it is a multifunction block so that it can be used on aod's with a carb, or cable setup and also works on c6 units on the opposite dimension of the block. I usually set throttle pressure dependant on other conditions no less than 33 psi warm in idle. I believe the spec is 33-35 so 34 is a good setting as well. To increase shift points the transgo part # aod-hp kit includes a high rev governor. That is the springs that were originally asked about. The high rev governor kit isn't very expensive . I think I paid $12 last time I bought one(several years ago). I'd suggest using the entire Kit I mentioned. It will allow manual shifts better than doing the 1-2-1 shuffle.
Alan
 
Thunderbird84 said:
Eeek! Don't set it that way, get a pressure gauge and set it from the TV port on the transmission. I thought that I had it set right, or close to it, and then I put a gauge on it. I started the car up, and the gauge read ZERO. Zip, nothing, nada. I nearly **** myself when I saw that. It turned out that the TV cable had to be pulled out an additional 1/4 to 3/8 of an inch to get the correct 34 PSI, even though the cable was set to the TCCOAs instructions. The entire gauge apparatus can be purchased from Sears for under $20, which includes the gauge. You need to cobble together the fittings and such, but it is still very cheap.

Well I agree that setting by the gauge is the way to go. I just recommended the article as most don't have the tools on hand and I hadn't heard of anyone having problems that way. Not that I've looked either...
 
Get the Lentech VB...in addition to being able to lock out OD and improving the shift firmness, it also changes the shift pattern (none of the others do) to allow manual up or down shifting in all 4 gears. Yes...you can actually start in 1st then shift (chirp) hold 2nd gear as long as you want then shift into 3rd or instead of shifting let off the gas and get engine braking in 2nd.

It will also shift automatically just like the stock AOD does.

David
 
David Neibert said:
Get the Lentech VB...in addition to being able to lock out OD and improving the shift firmness, it also changes the shift pattern (none of the others do) to allow manual up or down shifting in all 4 gears. Yes...you can actually start in 1st then shift (chirp) hold 2nd gear as long as you want then shift into 3rd or instead of shifting let off the gas and get engine braking in 2nd.

It will also shift automatically just like the stock AOD does.

David

I know this will sound really ingnorant, but, how do you shift a trans through four gears (1,2,3,od) with a selector that has (1,D,OD)?
 
The Lentech valve body allows for a 1-2-3 shift when OD is locked out via an electric selenoid. Once you are in 3rd you can then turn off the lockout to go into OD.
 
Ok so what I'm reading is that the VB reprogramming/replacement is a good way to eliminate this problem. If I wanted to adjust the TV pressure, where is the port? Where is the adjustment? And can I do it without a lift? Also what kind of work is involved with installing the shift kit (trans-go or Lentech) and lastly what can I do to make sure that nothing else is wrong with the trans? I dont want to spend a weekend installing a shift kit only to f ind out that my trans is shot.
 
gldiii said:
The Lentech valve body allows for a 1-2-3 shift when OD is locked out via an electric selenoid. Once you are in 3rd you can then turn off the lockout to go into OD.

Gotcha-Thanks
 
I hate to tell you this but if your tranny is basicly skipping 2nd like you mentioned and the rest of the gears shift too early just like you mentioned,
your tranny is toast and no valve body or shift kit is going to fix that. sorry. :(
 
MIKE 38sc said:
I hate to tell you this but if your tranny is basicly skipping 2nd like you mentioned and the rest of the gears shift too early just like you mentioned,
your tranny is toast and no valve body or shift kit is going to fix that. sorry. :(

Mike,

I'm glad that you got involved. I read the thread where you talked someone thru a rebuild and really hoped that I could get your input. My trans doesnt skip 2nd unless I'm at WOT. Any other time it shifts smoothly but early. If I dig in at 1/4 throttle or normal stoplight driving, it will shift 1-2@3300-3600 2-3 at about the same place and then into OD as quickly as possible it seems. If I drive in D it seems to have more pep but still wants to shift early. What are the shift points supposed to be? And how can I test my AOD to get a good feel for what is going on? :confused:
 
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