F-body driver

Hello guys
I noticed little problems with my 700r4

1)I lost lockup: even jumping the ALDL lockup terminals it wont lockup in any gear

2) When in 3rd gear and I let off the gas, it surges: RPMs go up and down from 1200 to 1000 like it tries to shift into something

3) downshifting from 4th to 3rd seems NOT firm at all, very soft

Fluid is between pink/yellow, very clear and NO burnt smell

T.V. is set propely and tighten

1-2 and 2-3 and 3-4 upshift is firm, for a stock 700r4.

Driving in manual I feel engine braking power

No signs of slipping

Why my trans is acting this way? 122500 miles

Thank you in advance

Bob88GTA

iTrader: (2)

Sounds like your TCC Lockup solenoid went to lunch (toast, bad).

F-body driver

Ok thank you! In order to change the TCC solenoid have I to open the case of the trans or I just remove the pan?
For the 3rd gear strange problem today I noticed that when I brake and rpms go down to 1200 rpm seems like the overrun clutch engages till it downshifts to 2nd

Bob88GTA

iTrader: (2)

You just might have an issue with the rear end on the downshifting /clutch engagement.
Is it a limited Slip diff? You may need to add the Limited Slip Lubricant to the diff. It will help disengage the clutch pacs in the rear and also prevent "chatter" from the rear when slowing to a stop and rounding corners.

JMO though.

Bob88GTA

iTrader: (2)

On the solenoid.....yes under pan

F-body driver

Yes I have a LSD diff without the special additive. Could this cause my problems? It also clunks when downshifting at the stoplight and it clunks when I put in gear

Bob88GTA

iTrader: (2)

Add the additive and do REAL SLOW figure 8's. In a parking lot. That should help, 6 oz tube. They all. Have clunk, not really a big concern.

Bob88GTA

iTrader: (2)

Add to the rearend. Take a turkey baster and take OUT 6oz and then add. Wash baster and use Thursday on the bird!!!! JK!!!!!

F-body driver

Ok thank you Bob! So have I to change my entire fluid or could I just put the additive into it? I hope I didn't hurt my axle. Back in 2007 my mech changed my axle fluid and he put SAE 80W 90W. Since 2007 I put 400 miles to the car

Bob88GTA

iTrader: (2)

Just add the additve. Take diff fill plug out and feel if there is room for more fluid, if so put it in. If not, take some out before you add it.

F-body driver

Ok Bob do I need a special tool in order to remove the plug?

Bob88GTA

iTrader: (2)

No, Just remove it. It should be plastic/rubber plug

NCC-2569

iTrader: (1)

AFAIK, you need a rather large Allen screw driver.
That's not just a rubber plug on there. The internal pressure would push that out.

Bob88GTA

iTrader: (2)

ON the rearend?????? Mine is a rubber plug

F-body driver

I would like to change all the differential lubricant, so I have a few questions ...
1) Are there in the market differential oils with the Limited Slip Differential Additive ?
2) IF YES, WHAT BRAND WOULD YOU SUGGEST ME TO USE ?
3) OR IT WOULD BE BETTER TO USE THE NORMAL OIL PLUS THE SPECIAL GM ADDITIVE ?
Thank you in advance

Bob88GTA

iTrader: (2)

yeah..and.....?

F-body driver

My questions are the following :
1) Are there in the market differential oils with the Limited Slip Differential Additive ?
2) IF YES, WHAT BRAND WOULD YOU SUGGEST ME TO USE ?
3) OR IT WOULD BE BETTER TO USE THE NORMAL OIL PLUS THE SPECIAL GM ADDITIVE ?
Thank you very much in advance

Bob88GTA

iTrader: (2)

Just USE THE NORMAL OIL PLUS THE SPECIAL GM ADDITIVE. Any well known gear oil is fine.

Castrol, Valvoline would be fine. Lucas has Synthetic but it's not necessary. Just keep it simple.

K & W Chemical TRANS-X Posi-Trac Limited Slip Gear Oil, Limited Slip Additive from parts store, Sta-Lube makes it. It's pretty common stuff

F-body driver

Thank You VERY VERY MUCH BOB FOR YOUR PRECIOUS HELPING HAND !!!!!!
I will see what I'll find at the parts store !

Bob88GTA

iTrader: (2)

When you get it put in, take it down to the Piazza Cavour and do some circles!

NCC-2569

iTrader: (1)

Yes, on the differential. I don't remember seeing any rubber there... but there's never a pic around when you need it.

This is kinda how I remember it:
http://www.installuniversity.com/ins...ug_locator.jpg

And this would be like my plug:
http://htsmall.ecklersfirebird.com/a...u/75-14479.jpg

Not saying that yours can't have a rubber plug, I'd just be confused to see it put in there at the factory.

Bob88GTA

iTrader: (2)

Mine, from factory, 88 GTA, 3.27 GEARS Limited Slip

IDK.......

NCC-2569

iTrader: (1)

That's the pickup-magnet on the inside of the cover.
No plug there on stock covers, at least not on mine :/

Bob88GTA

iTrader: (2)

Ok

F-body driver

Oh my God how you know my little Italian City?
Anyway tomorrow I'll go under the car and I hope I could unbolt the plug easy

Bob88GTA

iTrader: (2)

Ok. this is MY stock, untouched LSD from under my car 10 minutes ago. Bought new in 88. So, Like I said...IDK. Filled/drained Diff MANY times from this plug. Not getting into a pi$$ing contest.

Have a great evening NCC

Bob88GTA

iTrader: (2)

Good luck.If no PLUG on cover, use a ratchet on the side of the diff.

I Googled your city!

NCC-2569

iTrader: (1)

Haha, thanks. Good day to you, too

I definitely do not have such a plug, just the Allen screw on the diff's side.
But that's GM for you... different parts every year
Nice to see it, anyway.

Would be interesting to know if F-body driver has such a plug as well, so... let us know

F-body driver

Without jacking my car up (I have to buy jack stands) I am not able to find the plug. Anyway My trans fluid turned dark red so I drained 2 paints and filled with Dexron III.
That's a pic of the old fluid: it smells good, NOT burnt and debris free.
Could this cause my issues with my wrong Diff fluid?

NCC-2569

iTrader: (1)

That's not exaclty "dark red" anymore. That's brown and definitely needs to be changed, including the transmission oil filter.
You won't find any debris unless you remove the pan and take a look at the collector magnet and even then you might not find any.
IIRC the total amount of transmission fluid comes to roughly 16 pints, including what's in the converter... which you won't get out unless you remove the converter.

You won't reach the diff plug on the side without jacking the car up, except if you're as thin as a sheet of paper
Even then you would need to bend your arms impossibly to properly squeeze new fluid into the diff, because it's thick stuff and requires some pressure, especially when its cold.

F-body driver

I replaced Fluid and Filter 300 miles ago in 2010 (only the fluid in the pan)
Should I change it again?

NCC-2569

iTrader: (1)

Looking at the color, yes, definitely.
Remember, you only changed what was in the pan and that has mixed with the contents of the converter.
You've still got some changes ahead of you until the fluid's clean again

F-body driver

Ok, I'll do my best
An other thing I need to figure it out is:
In order to let the car shift into 2nd 3rd and 4th LETTING OFF THE GAS I have to let it off at around 2100 rpm. Is this normal for a stock 700r4 or could I have a shift reprogramming kit installed? Under light throttle it shifts over 3500
When it shifts into 2nd (letting off the gas) it doesen't chirp but I feel the slide bump

NCC-2569

iTrader: (1)

Do I get this correctly?
When shifting from 1st to 2nd under light throttle, your rpms are over 3500?
Not normal.
Sounds like a badly adjusted t.v. cable or maybe that cable is even kinked or sticking in some place.
Not sure if the throttle valve itself could be damaged, but I would start looking at the link on the throttle body of your engine and then work my way down to the transmission.

There are shift kits, yes, but they do stuff like changing pressures and causing firmer shift operations... stuff like that.
Your shift points can't be programmed. That stuff starts with the 4L60E transmissions

F-body driver

The t.v. is set propely.
I guess my governor or my valve body are sticky
For light throttle i mean 1/4 (more or less) of the throttle.
when the trans heats up well it shifts at about 3000 rpms under light throttle

NCC-2569

iTrader: (1)

I see.
With roughly 1/4 pedal travel my transmission don't shift at 3000 rpm.
Can't say where shifting does occur, but I only reach 3000 rpm before shifts when really kicking the pedal.
To which rpm does your engine drop after shifting from 1st to 2nd?
Does it go from 3000 down to 1000 rpm or something like that?
That's what I once experienced with wrong t.v. cable adjustment.
But yeah, could also be your governor or valve body. That would transcend my area of expertise, though.
Would be nice to have some of the other guys chime in at this point.

F-body driver

I made a short video that could explain better
As you can see, the "shift" yellow light on the dash appears but no lockup.
The 1-2 shift is made letting off the gas
The 2-3 is made with light throttle
The t.v. was set before starting the car

F-body driver

I just figured my t.v. cable was too tight and I got too much tv pressure.
I set it a little bit loosen than before.
Now it shifts no more harsh and shifts point went down to "normal" I think
Have I set it correctly?

I made a video too

https://www.youtube.com/watch?v=6Etj...ature=youtu.be

NCC-2569

iTrader: (1)

There's no way to see if that's "the" correct position, as it is individual to each car because the cable stretches a bit over time.
In the first video the 2-3 shift seemed a bit far apart.
During the second vid I was wondering why the car didn't go into overdrive.
Was it at operating temp?
Mine goes down to about 1600 rpm in overdrive, but I may have a different axle ratio than you.

F-body driver

In the second video it shifted into all 4 gears but I guess my lockup is gone!

NCC-2569

iTrader: (1)

Regarding lockup... perhaps the TCC solenoid has died.
Also, there's this strand of cables going to the transmission's rear end.
When you get under the car the next time, check it for corrosion or dirt, just to be sure.

F-body driver

Loosing 1 click of the tv the car is driveable well now but I think less line pressure is not good for the 3-4 clutchpack. What do you suggest me: max tight t.v. for max line pressure or 1 lick loosen for better gas mileage and soft feel?

NCC-2569

iTrader: (1)

Whatever suits you.
The cable should be correctly adjusted at any time and I guess if you loosen it one click and it shifts better, then that should be the right setting.
Why you need to do that and your tv cable isn't set right by the regular adjustment procedure... I can't say.
Very strange.

F-body driver

That's quite strange for me too.
Few years ago the t.v. was 2 or 3 clicks loosen (from the previous owner) so my trans overheated and fluid became dark red without burning
After this experience I set the t.v. as tighter as possible, infact now my trans didn't overheated anymore but I noticed the t.v. was way too tight and line pressure was huge, because when I put in gear the car bumped very hard and shifted way late and harsh.
With 1 click loosen now it doesen't bump anymore and shifts are quite soft.
Anyway I need a new tcc solenoid.
Could anyone suggest me a stock replacement unit?
Have I to change the pressure switches on the side of the valves too? Or should I only change the solenoid near the accumulator?