Second trans service after extended service interval?

[usapadyra]

Hey,

Can anyone weigh in on how much truth there is to the idea that if you have previously neglected to service a transmission, and then get it serviced, a second service should be performed a few weeks or months after?

Reading around online, there are certainly people here and there vouching for it, but it doesn't seem to be all that common a recommended practise.

The justification for the second service is that the fresh fluid, with its detergent effect, could potentially cause the filter to clog up with old buildup as it comes free and circulates. I understand the thinking, but I don't know if it's just one of those things that doesn't actually happen.

As I understand it, since the trans is sealed, the only 'particulate' material that can gather is metal shavings from the internals which should be caught by the magnet. Surely the varnish deposits etc just end up diluted / suspended in the new fluid since they aren't 'solid'?

The service history and function of the trans in my truck is as follows (1998 Exp V6 SOHC 2WD - 5R55E - I believe):

- Bought at 150000 miles
- Last transmission service on Carfax at 94000
- Around 189000 started getting slow shifting / flaring during 1-2 shift but only under low throttle conditions. Normal or heavy throttle still shifted fine.
- 190000 had transmission serviced. Got one slow shift after service, but that was it. Since then zero issues.
- Next 1000 miles, every 200 miles or so, I sucked up to 2 quarts out through the dipstick and replaced with fresh to gradually improve the condition of the fluid.


The transmission is the one thing I don't mind spending chunks on if there is worthwhile preventative maintenance I can do to keep it alive...now that I have money...I didn't really have any from 150000 miles through 180000

There's an independent transmission shop in town that has great reviews. Probably looking at $250 for the service (I don't have the means to lift the car). I guess my question is - is this is a worthwhile investment or a total waste of money?

Cheers

 

[Rick]

Besides gear wear the friction material on the clutches wear, so do sealing rings. That all contributes to the sludge seen in transmission pans in older vehicles. Some say that the new fluid will accelerate the wear of the friction material. I think that if the tranny is already on it's way out changing the fluid could cause it to happen a bit sooner. It's not very common to hear people say that changing their fluid and filter solved a problem they were having prior to the refill.

 

[usapadyra]

Besides gear wear the friction material on the clutches wear, so do sealing rings. That all contributes to the sludge seen in transmission pans in older vehicles. Some say that the new fluid will accelerate the wear of the friction material. I think that if the tranny is already on it's way out changing the fluid could cause it to happen a bit sooner. It's not very common to hear people say that changing their fluid and filter solved a problem they were having prior to the refill.

Good point, I hadn't thought about the other components breaking down and adding to the mix.

Luckily in my case the standard service fixed the issue I was having. It's been nearly 9000 miles since and the trans seems to be doing fine. I guess it had to be either a clogged filter, tired fluid or both in contribution.

I'm asking more about the validity of getting a second service done when previously it had been running the same fluid and filter for nearly 100k miles.

 

[C420sailor]

I’d make that decision based on the visual condition of the fluid. If you suck some out and it isn’t cherry red, I’d change it again. Your method will work fine, but I’d suck as much out as possible. Or better yet, use the cooler line bucket method.

To give you an idea of how a well-maintained tranny fluid should look, I do mine every 30k and it comes out cherry red and 100% translucent. Looks new.

The pan filters are not fine at all. 80-120 microns I believe. It would take a tremendous amount of sludge to block them. Metal particles should be caught by the magnet, which should have been cleaned.

This leaves friction material.

I run an external trans filter, which uses a spin-on FL-1A. Keeps the fluid very clean. I highly recommend it. Just make sure you securely mount it, and that you pay special attention to direction of flow.