I just purchased a 1995 torch red convertible with 65k miles that runs well and looks perfect but...in as there were no maintenance records available. I decided to do a baseline maintenance on the car and checked it in at a local Corvette specialist who is well regarded. I had the radiator flushed and refilled, hoses and belts checked, differential oil changed and requested a change of trans fluid. The shop owners response was "If the existing fluid is red in color we can change it but...if it is brown we cant." As a lurker on this site I know that to be sound thinking and though the fluid color was brown he did say that the transmission might be as much as 50k miles left before it goes grenade on me..

My question is this "Should I simply drive the car until the transmission goes up in smoke and pay $$$$ to repair or...is there some kind of minor overhaul that is commonly practiced that would avert a catastrophic failure?" I haven't driven a car with an automatic transmission in 21 years and my ignorance is clearly worn on my sleeve and furthermore It's probably a stupid question but then...it ain't stupid to me.

 

Find a different shop or there was a misunderstanding of what you were getting. Today transmission fluid flushing is a popular service. The old fluid is pump out pushing new fluid in. It replaces over 95% of the fluid. It doesn't fix anything with today's fluids. A transmission fluid flush on a vehicle with heavily discolored fluid can turn a weak shifting transmission into a inoperative one. The thick crappie fluid is the only reason it works at all. The new fluid passes by the leaking internal seals. Shops have been advised not to flush transmission fluid on vehicles with heavily discolored fluid.

A transmission service is dropping the pan and replacing filter or cleaning pick up screen(s). It only replaces up to 75% of the fluid depending on design of transmission and how much fluid remains in torque converter. The pan is inspected for debris indicating wear or failure. Typically there should only be a small amount of fine metal powder in pan. There should also be at least one magnet, they are wiped off a replaced to the area of the pan they were at originally. Copper, bronze, or fiberish particles indicate internal repair will be required or to plan for. GM only recommends to pull pan. There are reusable pan gaskets for the newer transmissions. The 700r4 doesn't use one the 4l60e may. Sometimes the reusable ones are replaced with the old style gaskets. If the filter kit only comes with filter, the gasket is intended to be reused. Reusable gaskets a twice as thick as the old types,
it's like a rubberized metal gasket, if damaged or leaking it should be replaced.

 

transmission fluid oxidizes and changes color with age/use/heat. in and of itself, a change of color doesn't mean the transmission has been damaged. there is going to be normal wear and tear in the trans itself just from usage.

also, who knows if the trans has ever been serviced before and when, it could just be really old trans fluid

there are other indicators as Kevova said:

 

I suspect

I suspect that the fluid in the transmission is circa 1995 OEM stuff and the points both of you make changes the narrative. The new question becomes "Should I have the transmission serviced using the proper dropped pan method or not?"

 

The fellow who owns the first shop has likely 'been there and done that' when someone has requested a transmission service and then returned with a 'it's your fault' for the failure. His thoughts regarding a 'for hire' transmission service if followed by other shops could very likely have saved them countless hours of aggravation and legal fees.

I'd have no problem with a shop that has that offered up that response.

What do you do? Well I'd think a dump/filter/fill and then in a few thousand miles another pan removal for inspection and likely another filter/fill, very dependent upon the 2nd inspection maybe a 3d dump and fill.

Maybe you consider having a drain plug added to the pan or maybe buy one that has a drain and the 3d wouldn't require a pan removal.

I did this with a 4T65e of mine for a service where I had no idea if a service had ever been done.

Type of fluid gets debated frequently.

 

The OP reply I guess was deleted???
I don't do transmission services at home, because it can make a mess in a hurry. I don't know what's to be gained by frequently changing fluid. I would have transmission pan dropped filter changed and refilled by a reputable shop. If you're not noticing a shift problem or noise, odds are it will be ok. If the pan was pulled and clean, then later you felt the need the fluid could flushed. If there's excessive material, you should be advised of what the tech believes caused it. Then decide either drive to it stops or schedule repair. The dexron available today is designed to go over 100k miles under normal driving. Many service centers will push 30-50k which falls under extreme driving conditions.

 

My thanks to all for giving me a less catastrophic perspective on this. Forums like this are a treasure to us C4 newbies

 

I use TranSynd in my Allison transmission and will do a drain and refill with it eventually on the Corvette. Transynd is a little more expensive, but it is worth it IMO.

I get mine from a diesel service center that is authorized to work on Allison's. I find it less expensive to purchase it from them, rather than the more well known online sites.

I don't know if the older 4l60E transmissions have compatibility issues with newer trans fluids but it is a detail we all should look into. Allison had a serial nbr cutoff that specified that transmissions before a certain point needed Dexron-III (or equivalent full synthetic in the specification range) to be used due to later versions of Dexron degrading seals.

With the price of an Allison rebuild what it is, is the reason for me using TranSynd. The same will apply to our cars (possibly). It is well worth doing the research.