Fourth Gear

bowez

Registered User
Well in my run yesterday all was good until fourth gear and wondering if anyone can give me some ideas what to do to help out either getting into, stay in or just dealing it. It a stock AOD, and after yesterday I don't really see a point in dumping more money into the motor (heads and cam) if just going to keeping bouncing between 3rd and 4th and the back half, oh I'm running 3.73s.
 
Well in my run yesterday all was good until fourth gear and wondering if anyone can give me some ideas what to do to help out either getting into, stay in or just dealing it. It a stock AOD, and after yesterday I don't really see a point in dumping more money into the motor (heads and cam) if just going to keeping bouncing between 3rd and 4th and the back half, oh I'm running 3.73s.

Stock AOD's suck they shift like my grandma and WOT in 4th wont last long you may want to consider a valve-body upgrade with a OD delete switch Lenteck is the most popular but there pricy.
 
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So a new VB will help hold 4th at WOT, cause with the 3.73 90mph/4500RPM is as high as I feel safe to go in 3rd. Currently I have a stock rebuild with less than 6k miles, so the shifts are fine for me, its just the WOT issue.

Would it be better to throw more power at it so can run it a bit easier in 3rd and 4th?
 
Stock valve train and blower efficiency.

My last engine dropped a valve at 4k, so unless the production line parts are better than a factory reman personally I don't like to go beyond 4500, until have new cam, valve train and heads. Which goes back to orginal question on how to deal with the WOT kick down in 4th gear.
 
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so unless the production line parts are better than a factory reman

IMO YES! You either had a poorly built motor or extenuating circumstances that led to your last engine failure.

WOT kick down in 4th gear.

A few assumptions:
you aren't just working on your 1/4 times. :)
you have a stock AOD since you have a stock engine.

I'm betting you are letting the car shift into 4th and then trying to find the optimum throttle position to hold OD and while doing that you end up downshifting into third and then back into fourth.

Well doing this will greatly shorten the life of the AOD band and balloon the torque converter.

IMO your best bet would be to have the AOD professionally rebuilt with a aftermarket AOD band, a manual valve body and a heavily strengthened torque converter. I do not believe there are any aftermarket setups that will allow full throttle power in fourth besides a manual valve body. I sure could be wrong that there aren't any setups do do this (besides a manual valve body) and that a manual valve body would solve your dilemma.

If you are a speed junkie, you'd be better off adding hp and removing the 3.73's and going back to 3.27's. I enjoyed my stock SC with 3.27's more that I did with 3.73's. That car didn't like them. Then again if you are a speed junkie the best solution is 300 plus rwhp, a 5-speed and 2.73's. :D
 
Well doing this will greatly shorten the life of the AOD band and balloon the torque converter.

IMO your best bet would be to have the AOD professionally rebuilt with a aftermarket AOD band, a manual valve body and a heavily strengthened torque converter.

If you are a speed junkie, you'd be better off adding hp and removing the 3.73's and going back to 3.27's. I enjoyed my stock SC with 3.27's more that I did with 3.73's. That car didn't like them. Then again if you are a speed junkie the best solution is 300 plus rwhp, a 5-speed and 2.73's. :D

Disagree with you:eek: I had a stock AOD with 144,00 miles on it and just added a Lentech valve body. Made all the diffrence in the world. I didnt spend all the extra money to strenthen the TQ converter, didnt add bullitt proof bands and it shifted hard and never failed. Far as I know it is still running strong in your brothers car:rolleyes:

Put a lentech valve body in you transmission, leave the gears alone. Best mod I did for the car from a performance feel. You can do it yourself, it doesnt take long, and once in place doesnt require any more maintenance

I am a speed junkie and I happen to like the AOD just fine

Ken
 
Disagree with you:eek: I had a stock AOD with 144,00 miles on it and just added a Lentech valve body. Made all the difference in the world. I didn't spend all the extra money to strengthen the TQ converter, didn't add bullet proof bands and it shifted hard and never failed. Far as I know it is still running strong in your brothers car:rolleyes:

Put a lentech valve body in you transmission, leave the gears alone. Best mod I did for the car from a performance feel. You can do it yourself, it doesnt take long, and once in place doesnt require any more maintenance

I am a speed junkie and I happen to like the AOD just fine

Ken

I hate to tell you this but your torque converter you sold my brother was showing signs of ballooning. It was just as ballooned as the one that was removed. I believe the original transmission had a bad AOD band and ballooned transmission because I did exactly what I described above.

My definition of a speed junkie is top end speed.

I don't think you ever pushed your car hard in 4th.
 
I hate to tell you this but your torque converter you sold my brother was showing signs of ballooning. It was just as ballooned as the one that was removed. I believe the original transmission had a bad AOD band and ballooned transmission because I did exactly what I described above.

My definition of a speed junkie is top end speed.

I don't think you ever pushed your car hard in 4th.

For his power level, I still stand by my statements. Top speed is only one aspect of performance. Majority of the guys here on the SCCoA are 1/4 milers or run their car on the streets stop light to stop light. Not a lot, im my humble opinion, trying to see if they can turn 150mph, a few but not a lot. If one is dynoing for HP numbers than the holding of the AOD in 3rd is really needed. My old stock tranny, if it was balloning like you said, was working well for me at 300 rwhp and 400+ rwtq which is a lot higher than the gentleman, who started the thread, car is producing. And you are completely right about me not pushing my car hard in 4th. Im not a land speed racer:rolleyes::D

Ken
 
You need to do the driver mod.

There is nothing wrong with spinning a motor to RPMs it is designed to see.

There, however, is something wrong with using an overdrive gear in a racing situation. Overdrive is not designed for what you are using it for.

Stop abusing your transmission.
 
So a new VB will help hold 4th at WOT, cause with the 3.73 90mph/4500RPM is as high as I feel safe to go in 3rd. Currently I have a stock rebuild with less than 6k miles, so the shifts are fine for me, its just the WOT issue.

Would it be better to throw more power at it so can run it a bit easier in 3rd and 4th?

Rev the motor to 5500..it's not going to hurt it. If you really want to be able to shift into OD at WOT and hold it, then install a Trans-Go shift kit. I don't reccomend it because it's hard on the OD band, but at stock power levels it will probably hold up for a long time.

David
 
I'm no AOD expert but I dont think your going to last to long holding WOT in 4th (Overdrive) gear. The lenteck has a OD delete function that locks out 4th and holds the car in 3rd its activated with a switch. Its built that way because the 4th Overdrive band in our AODs cant take WOT stress. For a pricy option you could try this http://www.gearvendors.com/racing.html
I have one on my 93 it has 4:10s in it. the gear Venders unit shifts harder than my lentek modded AOD
 
Not going to get into a p-ing match and argue about power level (since have no dyno to back it up) but I do feel with the fully ported M90, Maf/TB, 42#injectors, 2.5/3/2.5 exhaust and Double IC am above stock power level, but yes below the 300RWHP most likely.

Top speed I do enjoy, but is not the main use of the car. Though the concern is the upshift light screaming at me. Though if it will survive the occasional trips up into that range I'll just take it out of OD.

Though I do understand for longevity the need for the TC upgrade and a 2" carbon OD band. I just didn't/don't see how a VB upgrade will help with 4th gear issue.

As for the gearvendors option I'd rather just go to a different tranny all together that spend that kind of money--top speed anit that important.
 
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The vb upgrade increases line pressure which hardens shifts and increases the life of the transmission.

What year is your blower and who ported it?
 
94/95 Magnum Powers II

By my understanding of Jerry's article isn't it better to increase fluid volume and only increasing pressure (like trans go does on the 4R70w) can be a bad thing; either way a VB upgrade alone doesn't address my original issue.
 
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Wow. Mike was ribbing me for not being subtle enough, but Jeez, I guess you missed it....

The problem is not the transmission. The problem is that the owner does not have any clue what he is doing.
 
The vb upgrade increases line pressure which hardens shifts and increases the life of the transmission.

What year is your blower and who ported it?

Again I'm not an AOD expert but the issue with 4th isn't line pressure but the band/design itself, the tranny just isnt designed for repeted full power in 4th. Foutth gear was designed as a overdrive at cruse to increase MPG. if your running out of gear (in 3rd) Option A: put some taller tires on it. Or, Obtion B: (perfered) you might consider reving up to the factory redline
 
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94/95 Magnum Powers II

No such thing. MPII were 89-93 superchargers with the back cut off and a new back epoxied on.

Again I'm not an AOD expert but the issue with 4th isn't line pressure but the band/design itself, the tranny just isnt designed for repeted full power in 4th. Foutth gear was designed as a overdrive at cruse to increase MPG. if your running out of gear (in 3rd) Option A: put some taller tires on it. Or, Obtion B: (perfered) you might consider reving up to the factory redline

I was trying to give a short reason why a VB is a good thing for any AOD I wasn't trying to say it was the solution to his problem..
 
The stock AOD will not hold 4th at WOT. You must upgrade/shift kit the VB to allow this and stop the 3-4 shifting, if not you will burn the OD band very quickly.
 
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