Question: Clutch slipping

[Rocketkid]

I have 1981 automatic transmission.

The car starts and goes in gear just fine. It also shifts normal.

The problem is when going uphill I can see the RPM going up while on the same speed, similar to a manual transmission slipping.

I haven't serviced the tranmission for a while would that help?

Is it worth changing the clutch only (since I'm not doing it myslef) or should rebuild the tranmission?

I bought the car used and I put 80K on the transmission. it has 180k now.

Sam

 

[LLC5]

With 180k on the transmission and no services, you probably need transmission work, not just a fluid change. Have it diagnosed properly by a reputable transmission shop first since you are not doing the work yourself. If the transmission has internal problems, then a full teardown and estimate of repairs would be needed.

 

[Rocketkid]

Not sure if the transmission has been rebuilt before I got the car when it had 100K

So the transmission might have 80k or 180k on it!

I serviced the tranmission when it had 150K, so it has 30k miles on the service.

 

[TimAT]

Check the fluid level- low will cause it to slip and high will cause it to foam.
Then smell the fluid and see what it looks like. If it has a real dark color and a sharp odor, that's bad. Should be pink to red and no bad smell. Use a white towel and wipe the dipstick- again, it should not have any real dark red or brown color.

 

[tim414]

Check the fluid level- low will cause it to slip and high will cause it to foam.
Then smell the fluid and see what it looks like. If it has a real dark color and a sharp odor, that's bad. Should be pink to red and no bad smell. Use a white towel and wipe the dipstick- again, it should not have any real dark red or brown color.

Just out of curiosity, if the fluid is reddish but seems to have some darkness when wipping dipstick onto white towel, does this mean the fluid needs changing? Reason I'm asking is my local GMC dealership (where I had my Yukon serivced until recently-now going to Chevy dealer so both vette and buggy go same place) tells me the way they service automatic tranny's is to hook up a pressurized pump type deal and it pushes out old fluid and same time replaces with new. I am left wondering if the filter is not changed what good does this do? My Yukon has 80k on it. Had tranny serviced when it had around 60k (Apr 2008). Every once in awhile I will tow my boat that weighs about 4500/lbs or my ATV trailor with (two) big boy four-wheelers (which altogether weigh less than boat) Bought buggy new in 2004. I plan to drive it till wheels fall off. I live in HOT (Texas) humid climate in summer and nominally cold in winter. I dont know why they dont want to change the filter. They say they will but it cost me more. When I took in for service they automatically did it (service) this way. It was afterwards I found out how they did it(reviewing bill after leaving dealer-called them and spoke to service mgr). I'm thinking they don't want to pull the trans-pan because....to hard for them to repl and not leak when done are my thoughts why they don't. Anyway, not changing filter kinda worries me, especially when I had it in for service, then few years down road it might fail because lack of service. The appearance of the fluid is that it gets hot, but not burnt i think. It has towing pkg also....3:70 (?) gearing I think it was. Thanks (if I dont make enough sense 'what' my question is let me know, I'll try to explain better. Trying to present details surrounding-I'm not a mech tech-I'm in medical field.) Thanks. Tim

 

[tim414]

With 180k on the transmission and no services, you probably need transmission work, not just a fluid change. Have it diagnosed properly by a reputable transmission shop first since you are not doing the work yourself. If the transmission has internal problems, then a full teardown and estimate of repairs would be needed.

Hey master tech!! pls see my question below, please.....have you heard of changing trans fluid and NOT trans filter? :confused does not make sense to me to change fluid and NOT filter.....thank you, tim

 

[TimAT]

I've seen lots of those machines that flush the entire contents of the trans and replace it- makes no sense to me to do that and NOT change the filter. Other than a marketing gimmick- "Hey we can flush your trans, 100% complete fluid replacement". I can't see much value. Even a change that just drops the pan and replaces the filter, you add 4 quarts or so to fill it back up- that leaves another 3-4 quarts in the convertor. Not a bad thing to get it all out, but not changing the filter?

 

[tim414]

I've seen lots of those machines that flush the entire contents of the trans and replace it- makes no sense to me to do that and NOT change the filter. Other than a marketing gimmick- "Hey we can flush your trans, 100% complete fluid replacement". I can't see much value. Even a change that just drops the pan and replaces the filter, you add 4 quarts or so to fill it back up- that leaves another 3-4 quarts in the convertor. Not a bad thing to get it all out, but not changing the filter?

So then if it were your buggy would you be o.k. with the present situation? I plan to have them remove pan and change filter and fluid when the big 100k service is done. Thoughts? thanks allot. tim

 

[Hib Halverson]

I have 1981 automatic transmission.

The car starts and goes in gear just fine. It also shifts normal.

The problem is when going uphill I can see the RPM going up while on the same speed, similar to a manual transmission slipping.

I haven't serviced the tranmission for a while would that help?

Is it worth changing the clutch only (since I'm not doing it myslef) or should rebuild the tranmission?

I bought the car used and I put 80K on the transmission. it has 180k now.

Sam

If you have 180,000 miles on the trans and it's slipping, overhaul the transmission.

 

[tim414]

I've seen lots of those machines that flush the entire contents of the trans and replace it- makes no sense to me to do that and NOT change the filter. Other than a marketing gimmick- "Hey we can flush your trans, 100% complete fluid replacement". I can't see much value. Even a change that just drops the pan and replaces the filter, you add 4 quarts or so to fill it back up- that leaves another 3-4 quarts in the convertor. Not a bad thing to get it all out, but not changing the filter?

I suppose I am relieved that I am not being ripped there, but I am with you, I do not understand the reasoning behind leaving the dirty filter. Unless when replacing fluid it cleans the filter leaving only 'solids'. Thank you.

 

[TimAT]

GM auto trans filters are on the suction side of the pump- running clean fluid thru the filter will wash out any goo that it might have caught, but where is it going to go? If it passes thru the filter, it's going into the fluid circuits in the trans before it gets out to the cooler lines. And with that, it may also open up the pores in the filter media. The flush machines don't really run much pressure, but they still are not going to clean the filter out. Any trash caught in the filter is going to hopefully stay there. Get enough trash and the filter is plugged. Or at least it's restricted. Not a good thing.

I do like the idea of the flush in the respect that it also replaces the fluid that's in the convertor. Years ago, there was (maybe still is?) instructions on drilling and tapping a 1/8 pipe plug into the convertor so you can drain it. IIRC, the later convertors with the lockup were real critical about where and what angle the hole was.

 

[LLC5]

Hey master tech!! pls see my question below, please.....have you heard of changing trans fluid and NOT trans filter? :confused does not make sense to me to change fluid and NOT filter.....thank you, tim

Yes, I have heard of it transmissions being serviced that way, and no I would not recommend it without replacing the filter also. Replacing the filter is the only proper way to service the transmission.

 

[Txbobcat]

I think you are in for a tranny overhaul.

 

[tim414]

Yes, I have heard of it transmissions being serviced that way, and no I would not recommend it without replacing the filter also. Replacing the filter is the only proper way to service the transmission.

Thanks to both you guys for info/opinion. I wish now that I'd taken the offer from service mgr that day....when I found out that they had not rpl'd the filter I called the s.m. and he offered for me to bring it back and they would do it the 'right' way and credit the money I had already paid. After he continued to reassure me that what they had done was completely appropriate, I took his word for it and went along. I sure am disgusted with this kinda crap....I'm glad I found this site for my Vette....anyway....thanks again....tim

p.s. it just occured to me that I started asking my question when it was another guys thread looking for answer to his problem....is that 'thread-jacking' ? :ugh I apologize to that guy....do my own next time....tim

 

[73shark]

Surprised that a GM dealer would do a flush & fill w/o changing the filter. When I had my wife's Tahoe done, they did both. I agree that it doesn't make much sense to run clean fluid thru a dirty filter.

I do remember back in the day that auto mfg said you just needed to replace the engine oil filter every other oil change. Never did go by that.

 

[tim414]

Surprised that a GM dealer would do a flush & fill w/o changing the filter. When I had my wife's Tahoe done, they did both. I agree that it doesn't make much sense to run clean fluid thru a dirty filter.

I do remember back in the day that auto mfg said you just needed to replace the engine oil filter every other oil change. Never did go by that.

I really like the color of your vette... orange is my favorite...

 

[73shark]

Thanks. My wife picked the color 37 years ago. If I were to get a new one, would get Atomic Orange.