Tranny slips at the top of 2nd at wot and shifts all over the place - 2003-04 Mach 1 Registry Owners Club

WhiteautoMach · 12-31-2011, 06:09 PM

From 1st to 2nd gear at wot. How do I fix at home?

GR8 WYT · 01-01-2012, 10:29 AM

Are you low on tranns fluid?

I got to know the 4r70W trans quite well recently (yours in a 4r75w i believe...same with some upgraded internals)

Your 1-2 recuperator springs may be amiss. I installed the Perfromance Auto valve body upgrade in my son's 03 GT with the 4r70w. These springs play a critical roll and I upgrade mine with the valve bodyl. Your valve body could also be loose (I did not torque mine down properly and is showed the same symptoms you are having.)

You need to take it to a shop that knows these trans. Your torque convertor may be giving up the ghost as well.

Just my opinion. It's a place to start. WHen you figure it out, close the loop and post what was wrong.

JoshMac · 01-01-2012, 11:14 AM

Is it a good shift then a slip, or does it seem to "slip into gear" and never have a pronounced shift? If it shifts good and then slips you may be looking into a rebuild. If it is a sloppy shift that never really has a defined shift it could be a fluid/filter issue.

We run TransX(from NAPA) in all our higher mileage trans services, and anytime we have a issue. We do a flush or a filter/fluid change and add the TransX. Check your fluid and wipe the fluid on a paper towel. Put a few "dipstick samples" on the towel and hold it up, looking for any dark particles and "shiny stuff".

WhiteautoMach · 01-01-2012, 07:53 PM

Quote:

Originally Posted by GR8 WYT

Are you low on tranns fluid?

I got to know the 4r70W trans quite well recently (yours in a 4r75w i believe...same with some upgraded internals)

Your 1-2 recuperator springs may be amiss. I installed the Perfromance Auto valve body upgrade in my son's 03 GT with the 4r70w. These springs play a critical roll and I upgrade mine with the valve bodyl. Your valve body could also be loose (I did not torque mine down properly and is showed the same symptoms you are having.)

You need to take it to a shop that knows these trans. Your torque convertor may be giving up the ghost as well.

Just my opinion. It's a place to start. WHen you figure it out, close the loop and post what was wrong.

I did a complete tranny service 2x then added no slip stuff and nothing helped. So it sounds like a tranny rebuild is in order? I'll post the fix once I find it. I may keep driving the car 'til she blows or sell it, don't know yet.

WhiteautoMach · 01-01-2012, 07:55 PM

Quote:

Originally Posted by JoshMac

Is it a good shift then a slip, or does it seem to "slip into gear" and never have a pronounced shift? If it shifts good and then slips you may be looking into a rebuild. If it is a sloppy shift that never really has a defined shift it could be a fluid/filter issue.

We run TransX(from NAPA) in all our higher mileage trans services, and anytime we have a issue. We do a flush or a filter/fluid change and add the TransX. Check your fluid and wipe the fluid on a paper towel. Put a few "dipstick samples" on the towel and hold it up, looking for any dark particles and "shiny stuff".

It's a good shift from 1st to 2nd, then at the top of 2nd from 5300-5800 rpm it will slip then a good shift to 3rd. This is at wot. It is fine at less than wot.

jaimoe · 01-03-2012, 10:02 AM

Sounds more like the torque converter is not staying locked.

punishermach · 01-03-2012, 03:43 PM

Quote:

Originally Posted by WhiteautoMach

It's a good shift from 1st to 2nd, then at the top of 2nd from 5300-5800 rpm it will slip then a good shift to 3rd. This is at wot. It is fine at less than wot.

does it look anything like this?

http://www.youtube.com/watch?v=J_gXM...baAUAAAAAAARAA

rhite95 · 01-04-2012, 03:12 PM

Quote:

Originally Posted by jaimoe

Sounds more like the torque converter is not staying locked.

That is what I was thinking also. Do you have a stock converter?

WhiteautoMach · 08-23-2012, 10:05 PM

Quote:

Originally Posted by punishermach

does it look anything like this?

http://www.youtube.com/watch?v=J_gXM...baAUAAAAAAARAA

Vid is gone.

WhiteautoMach · 08-23-2012, 10:05 PM

Quote:

Originally Posted by rhite95

That is what I was thinking also. Do you have a stock converter?

Yes.

rhite95 · 08-24-2012, 04:38 PM

My car was doing the same thing got a tune done and that fixed it.

WhiteautoMach · 08-25-2012, 12:41 PM

Quote:

Originally Posted by rhite95

My car was doing the same thing got a tune done and that fixed it.

I have a custom tune in there by a very reputable shop in my area with the Diablo programmer. Both he and my tranny guy said I need a new tranny to fix these issues. Did yours slip at the top of 2nd and shift all over the tach from 1st to 2nd at wot?

rhite95 · 08-25-2012, 03:37 PM

No the 1st and 2nd shift are good it would lock and unlock the converter going down the track.

WhiteautoMach · 08-26-2012, 12:38 PM

Quote:

Originally Posted by rhite95

No the 1st and 2nd shift are good it would lock and unlock the converter going down the track.

Mine only slips from 5200-5700 rpm at wot in the top of 2nd gear.

WhiteautoMach · 08-26-2012, 08:21 PM

I drove an '02 GT today and it slipped at the same rpm in the same gear! Must be a worn out tranny issue. This thing was bone stock all the way to the silencer.

12-31-2011, 06:09 PM	#1
WhiteautoMach Registered User Join Date: Oct 2008 Location: Reno, NV Posts: 472	Tranny slips at the top of 2nd at wot and shifts all over the place From 1st to 2nd gear at wot. How do I fix at home? __________________ '03 Automatic. No silencer, K&N FIPK, 3450# race weight, drag radials, cat back, custom tune, alum. driveshaft, intake spacer, raised scoop, underdrive pulleys, larger subframe connectors, synthetic engine oil, removed front sway bar, battery to trunk, 2.06 60', 12.99 @ 107.4

01-01-2012, 10:29 AM	#2
GR8 WYT Registered User Join Date: Aug 2002 Location: Hughesville, Maryland Posts: 594	Re: Tranny slips at the top of 2nd at wot and shifts all over the place Are you low on tranns fluid? I got to know the 4r70W trans quite well recently (yours in a 4r75w i believe...same with some upgraded internals) Your 1-2 recuperator springs may be amiss. I installed the Perfromance Auto valve body upgrade in my son's 03 GT with the 4r70w. These springs play a critical roll and I upgrade mine with the valve bodyl. Your valve body could also be loose (I did not torque mine down properly and is showed the same symptoms you are having.) You need to take it to a shop that knows these trans. Your torque convertor may be giving up the ghost as well. Just my opinion. It's a place to start. WHen you figure it out, close the loop and post what was wrong. __________________ Aluminator NA bottom end, rebuilt stock heads, Vortech V2, 3.90 gear, 514 RWHP, 468 RWTQ. Motor and tune by JPC. (Millersville, MD)

01-01-2012, 11:14 AM	#3
JoshMac Registered User Join Date: Jun 2011 Location: Boone,NC Posts: 405	Re: Tranny slips at the top of 2nd at wot and shifts all over the place Is it a good shift then a slip, or does it seem to "slip into gear" and never have a pronounced shift? If it shifts good and then slips you may be looking into a rebuild. If it is a sloppy shift that never really has a defined shift it could be a fluid/filter issue. We run TransX(from NAPA) in all our higher mileage trans services, and anytime we have a issue. We do a flush or a filter/fluid change and add the TransX. Check your fluid and wipe the fluid on a paper towel. Put a few "dipstick samples" on the towel and hold it up, looking for any dark particles and "shiny stuff".

01-03-2012, 10:02 AM	#6
jaimoe Speed addict Join Date: Apr 2007 Location: Miami, FL Posts: 648	Re: Tranny slips at the top of 2nd at wot and shifts all over the place Sounds more like the torque converter is not staying locked. __________________ Best time 1/8th mi--7.65@90MPH 2003 DSG Mach 1 99/01 Cobra front bumper Darrin-Matic w/3500 stall converter 100 Shot 4.10 Gears Stock Springs KYB AGX adjustable shocks/struts tubular LCAs UPR dbl adj UCAs Custom SCT Tune 255/40/18 front 295/35/18 rear FR500 Wheels Custom RAI UPR O/R X-Pipe Roy spacer Flowmaster 40's I may not be as good as I once was, but I'm as good once as I ever was." "Just an old man having fun"

08-24-2012, 04:38 PM	#11
rhite95 Registered User Join Date: Apr 2004 Location: FL Posts: 1,951	Re: Tranny slips at the top of 2nd at wot and shifts all over the place My car was doing the same thing got a tune done and that fixed it. __________________ 2011 Kona Blue GT500 Stock for now 2004 MACH 1 Competition Orange (SOLD) 2007 Sport Trac Limited Oxford White V8 4X4 Magnaflow cat-back SCT XCalibrator 2 K&N Drop in Filter

08-25-2012, 03:37 PM	#13
rhite95 Registered User Join Date: Apr 2004 Location: FL Posts: 1,951	Re: Tranny slips at the top of 2nd at wot and shifts all over the place No the 1st and 2nd shift are good it would lock and unlock the converter going down the track. __________________ 2011 Kona Blue GT500 Stock for now 2004 MACH 1 Competition Orange (SOLD) 2007 Sport Trac Limited Oxford White V8 4X4 Magnaflow cat-back SCT XCalibrator 2 K&N Drop in Filter

08-26-2012, 08:21 PM	#15
WhiteautoMach Registered User Join Date: Oct 2008 Location: Reno, NV Posts: 472	Re: Tranny slips at the top of 2nd at wot and shifts all over the place I drove an '02 GT today and it slipped at the same rpm in the same gear! Must be a worn out tranny issue. This thing was bone stock all the way to the silencer. __________________ '03 Automatic. No silencer, K&N FIPK, 3450# race weight, drag radials, cat back, custom tune, alum. driveshaft, intake spacer, raised scoop, underdrive pulleys, larger subframe connectors, synthetic engine oil, removed front sway bar, battery to trunk, 2.06 60', 12.99 @ 107.4

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