goomaan

iTrader: (2)

Ok I recently swapped out my original 2.72 drum rear end for an Eaton Posi 4.10 with disc brakes.

Great you say.... Well now my car can no longer goes over 65mph without bogging down and the RPMs are peaking from 6500-7500 when I do hit 65 (or 95 on my speedo, but that is a different issue).

I spoke with a few people whoes opinion I trust and they say the 700R is shot. The tranny is not shifting and that is why I am at a RPM so high when the speed is so low.

My question is; Is my transmission shot or do I just need to get lower gears. There are no MODS on the car yet other than the 3" Borla Exhaust.

84 z28

So your saying all of a sudden right after the rear swap this started happening ? No tranny problems before the swap ? And did you get your speedo recalibrated after the rear swap to compinsate for the new gearing.

8T9 BANDIT

u can have 4:56 gears and youre car shouldnt be spinning to 6k.. u must have lost youre od, or maybe 3rd..

1985WS6transam

iTrader: (4)

I agree, its a gear below overdrive cause with my 4.11s and 700R4 in 3rd gear it is at about 110 IIRC.

I would bet you are stuck in second gear.

https://www.thirdgen.org/calculations
13" radius 6000 rpms 4.11 rear 1.63 tranny is 69mph.

Whoever did it, did they try to adjust anything on your transmission for somereason? also, did you try to manually shift the transmission?

oh and i wouldnt keep winding it up to above 6000 if i were you glen, your engine might not last as long, then you will be with all the other guys including me that are building for power.


He doesnt need to get the speedo recalibrated if he doenst want to, I didnt redo mine and it will read that you are going 90 when you are really going 60... I have the same gears as him now.


Edit, oh and glen, if you do need a new transmission we can go shopping together haha. My guess is something needs to be adjusted, its not likely that you blew the transmission on your first drive on your new rear with a mainly stock engine.

sofakingdom

iTrader: (1)

No they're not.

The "tach" merely is.

Your tach is off, like they always are; they fail by reading higher and higher as they age. Ignore what it says, until you verify it against a piece of test equipment of known accuracy.

"Bog down" is meaningless gibberish. Describe what the car is ACTUALLY doing.

I doubt there's anything wrong with the transmission, that wasn't wrong with it before. Put that entire thought on the back burner.

8T9 BANDIT

i think you should be able to hear a car spinning to over 6k? tach working or not, glen is the car srceaming?

goomaan

iTrader: (2)

Did not do the speedo yet because I was not sure if I was going to stay with the gears.

The reason I changed the rear is because I was not happy with the lack of power the car had. A suggestion made by my mechanic was to change the gears. I think there may of been a tranny problem that was just not noticable until I did the swap. The new gears I think is helping exaggurate what may of been a preexisiting problem.

No there were no adjustments done to the tranny. This sucks I want to start using the car for the season already. The night we came out for the meeting I thought Sam and I were going to have to push the car home....

F..k so does anybody have a good tranny to sell
----------
The fat lady is singing!!!!

Let me put it this way, with these gears I can not even spin the tires

wolfspirit187

Check the dowshift cable on the trans it self it might be binding up so it keeping u in a gear even if you manually shift it will keep you in a gear could also be the gov in the back might be sticking it tells the trans when to shift by speed(pressure ) if it sticking it might hold it in a gearthinking it itsn fat enough to go to the next gear but try manually shifting it and let us know (oh and bog down if it has stock Igition system (sorry lously speller) around 5500 it starts to die out causing a loss in power ( coil can't charge and discharge fast enough )so it seems like it bogging down but that is just my

wolfspirit187

Check the dowshift cable on the trans it self it might be binding up so it keeping u in a gear even if you manually shift it will keep you in a gear could also be the gov in the back might be sticking it tells the trans when to shift by speed(pressure ) if it sticking it might hold it in a gearthinking it itsn fat enough to go to the next gear but try manually shifting it and let us know (oh and bog down if it has stock Igition system (sorry lously speller) around 5500 it starts to die out causing a loss in power ( coil can't charge and discharge fast enough )so it seems like it bogging down but that is just my

1985WS6transam

iTrader: (4)

This sounds to me like it is literally stuck in 2nd gear, as in your not in first gear and it wont go into 3rd or 4th. Even in my 305 with a blown headgasket with 4.11 gears the tires spun.
Do you feel it shifting from first to second?

wolfspirit187

if you have a v8 engine stock at that rpms well you might have a 2 ton paper weight soon but a v6 ok high but ok not to good on it but ehh.. the not buring ties you might be in 2nd gear from take off would make it hard to spin the tires in that gear from take off does it seem to take off slow/ higher rpms then normal at that speed

Charged350

iTrader: (1)

wierd, get in the car, have sumone with you, put the car in od and drive it, have the person watch the rpm and look out for when the tranny shifts you will feel it, and count the gears that the car goes through the accelaration drive, if it doesnt shift 3 times....then you need a tranny...check the fluid and check your oil in the motor....could be a shot converter also...but i doubt it

goomaan

iTrader: (2)

I was so disgusted with it I put the cover back on and stuck in the garage. I will try to pull it out this weekend and see if she is shifting.

Oh and for the person who feels my tac is just off. Then how would you explain the engine reeving and the car going slow. I see you are a senior member and I could say without a doubt know more about mechanics then I do. But instead of trashing a post how about trying to offer some constructive criticism...

"(oh and bog down if it has stock Igition system (sorry lously speller) around 5500 it starts to die out causing a loss in power ( coil can't charge and discharge fast enough )so it seems like it bogging down"

sofakingdom

iTrader: (1)

The reason I suggested the tach, is because you can be just about 100% certain your engine IS NOT running at 7000 RPM or something.

I have a handful of those tachs. EVERY ONE reads high. One reads about TWICE the actual RPM. The one in my car, is (or was, when I put it in, anyway) about 3-5% high. I've heard of them reading more tahn 3 TIMES the actual RPM before.

Sounds like yours reads probably 20-30% higher than the actual RPM, maybe a little more; which is fairly typical.

I fail to see where anybody was "trashing a post", whatever that would be? What are you talking about?

A problem where the engine seems to start sputtering and missing and making no power at high RPMs, is usually either the fuel system, or the valve springs. Not the transmission in any case. Put that thought out of your mind, as I said.

People talk about "bog" around here all the time, and the problem is, that word seems to mean something different to everyone that uses it; so it's extremely hard to figure out what it EXACTLY is being used to describe. It's kind of like, just a buzzword for generally not running right, without anything more specific about how it's not running right. A more detailed explanation is better. Note also, that your somewhat more detailed explanation, was posted AFTER I asked for clarification of "bog"; I didn't get to respond to that originally.

goomaan

iTrader: (2)

Thank you that explaination makes a lot more sense than no it is not.
Forgive me for being a little sensitive on this isue just got hit with a 20k irs bill and am really pissed the f...king car decides now to give me problems.

1985WS6transam

iTrader: (4)

While his tach reading may be off by whatever amount, the question still remains why isnt it shifting?? sofakingdom, I have seen your other posts and most the time you are pretty damn close to diagnosing the problem, but here i think you missed the part where he said So even if he is reading his tach high and the speedo is off, the problem still remains why isnt it shifting. Also, sofakingdom, what do you think about the idea of it being stuck in second, certainly that would cause the "bog" off the line, and it not going into 3rd or OD would be the reason for the high RPMS at a low speed.


Glen, I just noticed this now What was the problem that night? Like what were the symptoms? Did it hesitate off the start or at part throttle? Mainly, did you feel the transmission shifting? You have to get the car good for our April meeting, I should be bringing mine this time. and although I dont have tranny problems yet, 500+ hp is going to burn up the tranny quick.

sofakingdom

iTrader: (1)

Well, the main reason I suggest him to check his tach FIRST, is this.

Ain't happenin'. Parts would be scattered all over his county if it was. So that's a great place to start when working on a problem of this type: get the metering indications straightened out.

Next, he didn't mention that the trans was broken BEFORE the gears went in. Raising the gear ratio DECREASES the stress (load) on the trans, because now, from the trans' point of view, it's EASIER to get the car moving. So I would not expect this change to have "broken" the trans. Therefore, if it wasn't broke before, then odds are, it isn't broke now.

Next, whenever people put in new gears, especially if they've never done it before, it can be a REALLY bizarre experience. They're all accustomed to the car sounding one particular way, feeling just so, and so forth, when driving down the road; gear swapping TOTALLY upsets that. Specifically, it makes the RPMs HIGHER at all times, especially when cruising, but the rest of the time too because the RPMs continue to climb during the time between when the trans decides to shift, until it completes the shift. So it just always seems like the motor is wound out to the extreme. Having a faulty (high) "tach" reading reinforces that impression in the mind of the driver.

In this case, going from 2.73 to 4.10, is just about as far as you can go, in this model of rear. I mean, that's a HUGE HUGE change. Radical, revolutionary, totaly upheaval. It's going to take some getting used to. The thing is going to feel like it's stuck in 1st gear 100% of the time, even it's working perfectly. BTDT.

One thing that the trans MIGHT need however, probably does in fact, is governor recalibration. Since it shifts based on the combo of throttle position and drive shaft speed, its brains are now scrambled. The throttle position during acceleration is probably less, because the load on the engine is less, which tends to make it shift earlier; and the drive shaft speed is higher, which also WILL make it shift earlier. So, now, the trans might be "stack shifting", i.e. shifting so fast at so low a speed with so little "jerk" betwen gears, that it's indistinguishable. That would be the ONE thing about the trans that might need work. Note however, that it's not "broken", rather, it might need recalibration to its new environment.

Next, now that the engine RPMs are so high all the time, a fuel starvation problem that before wouldn't have shown up until the car had been running at 100 mph for a minute, might now show up at 65 mph after 30 seconds. Again, a common issue with a HUGE gear change.

Anyway, step 1 is get the RPM measurement under control. Then, plug the gear and tire diameter into a gear/RPM calculator, and see if it makes sense. That right there will answer the question of, whether the trans is in the right gear. Then, deal with the fuel starvation issue. Then, go to work on the governor with a spring & weight "recalibration" kit.

But I'd say the chances of there actually being anything "wrong" with the transmision that wasn't "wrong" before the gear swap, are somewhere between slim and none. That's the wrong tree to be barking up. Wrong place to start just diving in and working on stuff, without knowing for sure that there's actually something wrong.

goomaan

iTrader: (2)

I really do not recall if there were shifting issues all I know when I hit about 60 my Check Engine light came on and I just had no more power to give her.

I doubt if I need a tranny or have engine issues she will not be fixed in time for April's meet and at this point July 5 is doubtful.

I do not want to do just a fix I want to do it right and get a FB ttrany and more hp with a new engine.

8T9 BANDIT

glen, ounce youre tranny is running right the car will feel totally different, especially with youre new gears. my advice is, get youre tranny done, and change that oil.. and youll be a happy camper when you hit the gas for the first time..

Charged350

iTrader: (1)

i gotta look at this thing...where do you keep it glen

goomaan

iTrader: (2)

I keep it in Cypress Hills.

Charged350

iTrader: (1)

yeah we gotta figure sumthin out

midwest

It will feel like it shifts four time.
1-2, 2-3, 3-4, lock up

Heres one way i use to fiqure out whats going on.
Drive it in 1, Accellerate at a normal street driving rate, and at about 15mph ( go off the speed on the dash) move the shifter into 2. You should feel a gear change or notice a drop in rpm. Your going off the speedo because, it is reading the output shaft rpm, and the governor is driven by the output shaft, so no matter how the road speed is effected by the diff change, the trans should still shift at the measured speedo speed.


if you feel it change, continue to go faster, then at about 25-30 shift it into 3rd. Or drive. You should feel it change or a drop in rpm.

if you feel it change continue to drive and about 45-50 shift it into od.
You should feel it change.


Now lets say you shift it from 1 to 2 and you dont feel or see a change. Leave it in 2 and giver her some gas, bring the speed up to 25-35. If it still doesnt shift, move the shifter to 3rd. If when you do this it shifts but it feel like a BIg shift or a large change in rpm. The 2nd gear is wiped out and the trans went from 1st to 3rd.

Lets say you shift it from 2-3 and nothing happens. leave it in 3rd and giver her some gas, bring the speed up to 35-45. If it still doesnt shift, move the shifter to od . If when you do this it shifts but it feel like a BIg shift or a large change in rpm. Then 3rd is wiped out and the trans did a shift from 2nd to 4th.

Lets say that the trans shifts each time you move the lever and then when you move the shifter from 3rd ( drive ) to 4th ( od) nothing happens. Continue to give her gas untill it sounds like its reving to high. If it still doenst shift. 4th gear is messed up.

The way that trans works, its possible to have both 2nd and 4th messed up but 1st and 3rd work fine.

goomaan

iTrader: (2)

Thanks I will try this on the weekend if the rain holds out.... I will post results

8T9 BANDIT

any results?????????????????

goomaan

iTrader: (2)

No it was my daughters birthday on Saturday and Sunday daddy had to take her to Toys r us to spend some of the gift cards she got.

To quote my boss (daughters and wife) "You are not going to play with that car on my birthday weekend" Someone explain to me how come when it is our birthday it last for a day but theirs last for the entire week!!!!

goomaan

iTrader: (2)

Ok i finally got the car out.

She appears to be shifting through the gears. The weird thing is when I get to about 60 it feels as if the car is slipping out of gear. If I let up on the gas she recovers but I can not get passed 60-65.

If the tac is near accurate I am at 6000-6500 RPMS. She idles at 1000.

I am dropping the car off in the morning to my buddy's shop I will let you know what they think it is....

Charged350

iTrader: (1)

lemme kno what they think....i think its some burned up clutch pack in the tranny

goomaan

iTrader: (2)

The verdict is in:

The trany does not have overdrive!!!!