transmission issue

[Jakegday]

Hello, 3 times in the last 2 weeks this has happened. Ill be sitting at a red light, then when it comes time to go, i press on the gas, the engine revs but the car barely moves, then about 1/2 a second to 1 second later youll feel it jerk (grab) then the car takes off and everything is normal. Whats goin on here? The fluid is full. I changed the fluid for the first time at 75000 miles, and have changed it every 25000 miles since then. When i say i "changed" it, i mean i did 3 drain and fills over the course of a week. car has 146000 miles..

should i start saving for a new transmission, or could it be something less severe?

 

[SatinSilver]

Is this on the Ranchero?

 

[Jakegday]

no, sorry, grand prix.

 

[Donald]

The ATf level was checked properly?

 

[Jakegday]

yes, warm engine/transmission, running, in park, level surface

 

[SatinSilver]

Ok, so 146k on the 01 Grand Prix. I'd try some cheap, simple fixes first to see if that helps. Is there an inline atf filter that hasn't been changed? If so that could be clogged and causing some issues. Not sure how durable this AT is.

I'd do a drain/fill and this time include a quart of Lubeguard. Available on Amazon and some some auto parts stores. Probably include the anti-shudder fix while shopping on Amazon. This is the only supplement I recommend other than some of the fuel system cleaners.

 

[Billbert]

But have you changed the filter?

 

[Jakegday]

yes, the filter was changed at 75000 miles, but not since then..

 

[demarpaint]

Originally Posted By: Jakegday
yes, the filter was changed at 75000 miles, but not since then..


I'd drop the pan and change the filter again. Refill and add a bottle of LG red. There's a chance the filter is plugged up, you won't know until you drop the pan.

 

[Challenger71]

I'd concur with satinsilver, in that filter can be clogged. I'd also add a bottle of lubegard after it has been flushed. Your GP likely requires a full flush vice drain/refill.

 

[Trav]

Need more information. Will it go into reverse readily or is this happening in both forward and reverse? Does it do it hot and cold or just cold?
A clogged filter that would cause this would have to be really clogged with material, chances are there is a larger issue.

These 4T65e units are known for the input clutch piston not sealing due to wear on the piston causing internal leakage, mechanic in a can wont fix it.
You need to get a scan tool on the job to see what is happening with pressures to accurately diagnose the problem.
At almost 150K the unit has probably had it and needs a rebuild, don't throw good money into one of these 4T65e units at that mileage.

Try a filter, who knows it may help for a while (i seriously doubt it) but i wouldn't go any further.
Don't let some local rebuild it get one from Triple edge Performance and have it installed.
Dave does all the upgrades to these things so they live a long time, he is the best in the business with these transmissions.

 

[meep]

sounds to me like pressures are falling. how long does it take to engage D, 1, R...?

but that's just a Guess with zero real diagnosis...

pressures fall from worn seals, gouged metal, worn pump. Writing may be on the wall.

If it were me, I'd drop the pan, clean everything I see, swap as much fluid as I can, refill partially with cheap ATF and then bit by bit add some lucas. the lucas thickens the fluid and will artificially build pressure. if that works, great--- it'll give you time to save for the real repair.

 

[zvm77us]

Had the exact same problem in my impala it was the TPS (throttle position sensor) and it did NOT throw a code. My mechanic couldn't diagnose it but a friend on the forums did. Don'y play with this because it can/will kill your transmission.
To check it follow the link below
http://www.ehow.com/how_4489318_troubleshoot-tps-sensor.html
http://easyautodiagnostics.com/gm_tps_3.8L/troubleshoot_bad_tps_1.php

 

[Milkman]

As always, very sage (and free) advice from Trav. He know what he is talking about.