Transmission slippage going into Overdrive

[57chevyragtop]

2002 Imp 3400 108k trans not serviced...started slipping today after warm up at 50 mph going into overdrive. shifting to 3rd is working OK. trans fluid smells a little burnt..and looks foamy (like overfull) but is not. I did not let it cool down before checking level as it needs to be warmed up anyway. I searched all the threads still available to view but did not find any that point directly to this problem. Most posts were hard shifting and cold slippage starting out. My question is> Should I try a fluid and filter change before trying to go further or just take it to a trans shop and let them diagnose the issue and be done with it? I neither have the tools nor know how to tackle any of this myself any more. Gettin old guys and it is way too cold. Just hoping to borrow the bucks to pay this fix which I fear will really hurt. I just had the LIM done a few weeks ago, ouch! I think I checked the fluid level wrong way with the trans in park, is it suppose to be in neutral PB on?

[maxwedge]

Sounds like you are past a fluid change, the o/d cluthes are most likely burnt, you know the rest.

[57chevyragtop]

Originally Posted by maxwedge

Sounds like you are past a fluid change, the o/d cluthes are most likely burnt, you know the rest.

Hoping against hope is not a good option? Yeah, kinda got that figured I think. I just have to keep this car at least 5 more years. Still better than car payments I think but when repairs in one year are over 50% of value you begin to question sanity. Just curious, I am thinking 12-1500 for this repair does that fit your ballpark thinking? Or should I be looking for +/- your opinion counts....

[j cAT]

Originally Posted by 57chevyragtop

Hoping against hope is not a good option? Yeah, kinda got that figured I think. I just have to keep this car at least 5 more years. Still better than car payments I think but when repairs in one year are over 50% of value you begin to question sanity. Just curious, I am thinking 12-1500 for this repair does that fit your ballpark thinking? Or should I be looking for +/- your opinion counts....

the transmission fluid in these pre 2006 vehicles is dexron III . many owners like you have this failure worn out transmission because they did not replace the fluid with the new GM approved DEXRON VI. dexron III is no longer the approved fluid for your vehicle. the reason is GM had too many warrantee failures so they had to use a synthetic blend with a slightly lower viscosity. this then resists turning into acid as the dexron III quicky does.


the fluid is checked with the vehicle being driven about 10-20miles at normal speeds. then parked on level ground. with the engine running and the shift selector in park.

use a clean cloth and wipe stick clean. check level several times to ensure its at the same point on stick ...with dirty contaminated fluid this is usually easy to see the level. this should be below the full mark but above the add mark.

if the fluid has air bubbles this is because its overfull. more fluid does not repair a tranny but those bubbles will rapidly destroy your transmission. this is because the fluid cannot be compressed to provide proper pressures. then you get slippage and rapid destruction.

you will need 2,ooo or so for a rebuild. I am sure you will find many shops with a good amount of work experience with these transmissions.

lots of failures with the dexron III and owners believing the vehicle manual which states you don't have to replace fluid every 30-40,ooomiles.

[57chevyragtop]

Originally Posted by j cAT

the transmission fluid in these pre 2006 vehicles is dexron III . many owners like you have this failure worn out transmission because they did not replace the fluid with the new GM approved DEXRON VI. dexron III is no longer the approved fluid for your vehicle. the reason is GM had too many warrantee failures so they had to use a synthetic blend with a slightly lower viscosity. this then resists turning into acid as the dexron III quicky does.


the fluid is checked with the vehicle being driven about 10-20miles at normal speeds. then parked on level ground. with the engine running and the shift selector in park.

use a clean cloth and wipe stick clean. check level several times to ensure its at the same point on stick ...with dirty contaminated fluid this is usually easy to see the level. this should be below the full mark but above the add mark.

if the fluid has air bubbles this is because its overfull. more fluid does not repair a tranny but those bubbles will rapidly destroy your transmission. this is because the fluid cannot be compressed to provide proper pressures. then you get slippage and rapid destruction.

you will need 2,ooo or so for a rebuild. I am sure you will find many shops with a good amount of work experience with these transmissions.

lots of failures with the dexron III and owners believing the vehicle manual which states you don't have to replace fluid every 30-40,ooomiles.

Thanks I knew I was pushing my luck on this mileage. I did not know about the advice to get dex III changed to dexVI, I somehow missed the conversations on that (those threads). I always get good help here and perhaps don't check in as often as I should in the past couple of years.
I did find a used trans for $400 but then you don't know what you got till it's in? then you got to find an installer. Gee! I just want my 57 chevy w/powerglide and 283, that was a crazy sell in my youth...who knew? Thanks again for all the help you provide here in this forum.

[j cAT]

Originally Posted by 57chevyragtop

Thanks I knew I was pushing my luck on this mileage. I did not know about the advice to get dex III changed to dexVI, I somehow missed the conversations on that (those threads). I always get good help here and perhaps don't check in as often as I should in the past couple of years.
I did find a used trans for $400 but then you don't know what you got till it's in? then you got to find an installer. Gee! I just want my 57 chevy w/powerglide and 283, that was a crazy sell in my youth...who knew? Thanks again for all the help you provide here in this forum.

I would get the tranny checked out. get estimate with a warrantee for 1yr in written form. get references of the shops work..

buying used with all the failures of these is not recommended.

alot of the cost is removal and install. rebuild parts not so much.

good luck.

[57chevyragtop]

I have an appointment set up for Monday 1 PM, He'll drive it and put a scan test on it. I will be driving about 17 miles from my location so it'll be warmed up when I get there. Probably use third gear most of the way there, no sense makng it worse before the check. I think it will be a couple of days after before they will do the work (my guess is). Should I ask about the Dex VI vs Dex III on this repair? I will post here the results of my visit Monday eve. This shop did the work on 92 Lumina TCC and treated me fairly as I remember it 2001.

[j cAT]

Originally Posted by 57chevyragtop

I have an appointment set up for Monday 1 PM, He'll drive it and put a scan test on it. I will be driving about 17 miles from my location so it'll be warmed up when I get there. Probably use third gear most of the way there, no sense makng it worse before the check. I think it will be a couple of days after before they will do the work (my guess is). Should I ask about the Dex VI vs Dex III on this repair? I will post here the results of my visit Monday eve. This shop did the work on 92 Lumina TCC and treated me fairly as I remember it 2001.

as you may already know dexronVI is more expensive than the DEXRON III. so I would make sure that he is aware that you do not want this low quality fluid used.

because GM does not license this fluid now , the quality is more of a concern.

since the place of business is still in operation that may indicate they are providing good repair work .. still having a warrantee and periodic checks should be part of the repair. in written form.

[57chevyragtop]

Thanks j cAT, I'll be sure to get it all in writing, I certainly hope he already knows the fluid update from GM....If not maybe it's the wrong garage to start with. He's been there quite a long time so he must be doing something right. Right now it's just the wondering the what if's that bother me. Truth is I should have gotten this fluid changed 10k ago at least. Sure wish I hadn't missed the VI fluid knowledge post(s). Is It called dex 6, speaking wise?

[j cAT]

Originally Posted by 57chevyragtop

Thanks j cAT, I'll be sure to get it all in writing, I certainly hope he already knows the fluid update from GM....If not maybe it's the wrong garage to start with. He's been there quite a long time so he must be doing something right. Right now it's just the wondering the what if's that bother me. Truth is I should have gotten this fluid changed 10k ago at least. Sure wish I hadn't missed the VI fluid knowledge post(s). Is It called dex 6, speaking wise?

yes that would be the correct name. on the fluid container however it says VI.

I have had issues with these type repair shops installing this dexron III it is cheaper at your expense.

just remember GM no longer approves of this fluid.

GM should have notified all of us that purchased these from the dealership so that this would reduce failures/cost.

I was lucky to have an aircraft engineer steer me away from dexron III back in 1998. I use mobil synthetic transmission fluid.

with a new GM vehicle changes have been made . now most all must use dexron VI for best performance...

if do do buy a new GM vehicle make sure you use the correct engine oil . they now require on some engines this super synthetic mixture that works with the engine fuel / power controls this is to increase fuel MPG.

many new vehicle owners have engine oil loss due to these new GM engine designs.

[57chevyragtop]

That's good to know. I don't plan on buying a new used car for at least 4/5 years. Repairs are still better than car payments at this point. Though I must say this Impala has cost me more in repairs than any car I have ever owned, IE. hub bearings 3, LIM, water pumps 2, Brakes Rotors and pads x3, these last rotors I got though are lasting really well. No electrical problems other than one battery 6 years ago, which is probably due anytime soon. OH, one alternator as well. This trans work will really kick it up.

[j cAT]

Originally Posted by 57chevyragtop

That's good to know. I don't plan on buying a new used car for at least 4/5 years. Repairs are still better than car payments at this point. Though I must say this Impala has cost me more in repairs than any car I have ever owned, IE. hub bearings 3, LIM, water pumps 2, Brakes Rotors and pads x3, these last rotors I got though are lasting really well. No electrical problems other than one battery 6 years ago, which is probably due anytime soon. OH, one alternator as well. This trans work will really kick it up.

I also have found GM vehicles of the 1980 era to be much more reliable and durable. with the way these are designed using testing and computer models they make these vehiles to go about 100,ooomi or/and 10 yrs then the cost to repair is so high at the dealership they will steer you to a new vehicle ...

well reading the reports from these new owners I can see why GM wants the feds out of the corporation , as they are going back to the pre bailout mentality . I plan on purchasing a non GM vehicle next time. customer support from GM is non existant . they play stall games and hope you will get frustrated and not come back with widespread expensive warrantee issues.

your transmission had a huge failure rate. best get it fixed properly.

[57chevyragtop]

Well, I took it to the trans shop today and the owner drove it, scanned it, couldn't find anything or it would not do what it was doing....He told me what it could be and showed me the part and what it might be that's starting to happen. Told me not to do anything but keep an eye on it and when I think it's happening to drop it to 3rd to see if I feel a downshift or not. Then check back with him in a week or two. He said fluid looks fine and the level is good, and pointed out not to change fluid just yet as it could make it worse if clutch material is parting off. So he advised a wait and see what happens for a bit and come back if I think it's acting up again. He pointed out that I was smelling radiator fluid leaking from coolant temp sensor and he tightened that up for me.

[j cAT]

Originally Posted by 57chevyragtop

Well, I took it to the trans shop today and the owner drove it, scanned it, couldn't find anything or it would not do what it was doing....He told me what it could be and showed me the part and what it might be that's starting to happen. Told me not to do anything but keep an eye on it and when I think it's happening to drop it to 3rd to see if I feel a downshift or not. Then check back with him in a week or two. He said fluid looks fine and the level is good, and pointed out not to change fluid just yet as it could make it worse if clutch material is parting off. So he advised a wait and see what happens for a bit and come back if I think it's acting up again. He pointed out that I was smelling radiator fluid leaking from coolant temp sensor and he tightened that up for me.

did he pressure test the tranny. there is a pressure port. there is a testing proceedure moving the gear select and watching pressure response. with these results you/they can determine the failures internal.

I would expect lower pressures than normal causing slipage and loss of proper upshift.

call him/another shop and ask about this. this if just a worn valve should be done now not after the tranny gets damaged..slippage creates high heat damaging the fluid. worn valve will lower the pressure.

[57chevyragtop]

Thank-you j cAT, No, he did not do a pressure test, and I do know about the test port but didn't think to ask him. I will however stop and talk to him and ask. I was not aware that low pressure at the port would indicate a valve problem or anything else for that matter. He might not have done that test because he didn't think it necessary at this point or being his garage was full. If I remember right the port is pretty difficult to get at, under the throttle body below the thermostat area. I'll look tomorrow in the daylight to see how accessable it is. Maybe the air intake box has to come off? I will keep your suggestion in mind for sure. I will post on this.

Do you use a oil pressure test guage or something different? What pressure is considered low? 20psi 10psi 1/4 NPT fitting I think....

I will have to go to the library and look up the procedure on Alldata for a better understanding, hey they got diagrams...but you know that. I have online access to some repair info but not as refined as alldata.