I just looked at a 1994 Buick Roadmaster wagon today, jerked some when shifting gears (1st to 2nd I think)?

Auto or manual? Has the transmission fluid ever been changed?

--scott

Well, it would help if you knew what car I was talking about.

It's auto.

It has 130k. Brown liquid tells me it hasn't been changed.

Change the fluid and filter. It might run a little better.

It's about due for a new transmission then. It might clean up fine with a fluid change and drive great for a while longer. Then again, it might not.

It would not seem out of the question to ask the seller to change the fluid. However, if they didn't change the transmission fluid... what else didn't they do?

--scott

Or it's been changed but got brown again. If it's jerking 'sometimes' I would be inclined to think changing the fluid is not going to improve it.

I didn't go over 40, just ran it up and down this road a few times). Didn't jerk every time.

The tranny fluid was clear but brown. What's the chances the problem could be rectified w/a new filter

and fluid change? I like to change the fluid a few times when buying a used car. 130k mileage.

Cheap, but don't have the facilities or desire to do a tranny swap if need be.

Car has been sitting for 1.5 years. Also needed a fuel pump, which the owner did. TIA.

chances are there is built up crud in the valve body of the transmission. What ever you do, DONT power flush it. As far as i can tell, in older gunked up units that will just put more crud the in valve body and maybe cause more issues.

maybe just a conventional flush with a bottle of tranie medic and see what happens.

bob

well it doesn't look like I'm buying the car. Love that model, I'll just ha ve to look for another one.

what I've been taught to do is change the fluid 3x at 1,000 mile intervals. That power flush stuff is crap.

Technically you could change it once, periodically pull the fluid out the d ipstick with a pump, filter that, put it back in. Then maybe just drop the pan and change fluid and filter 1 more time. What do you think? That was on e thing I love about the Venture, 7.4 quarts spilled out when you dropped t he pan. And it has a beautiful reusable ribbed gasket (my 2001 anyway). Oth er cars where 1/2 or less of the fluid came out when dropping the pan - I g uess you have to use the cooler lines to change the fluid (a quart or so at a time I'm told, by cranking). Or what I envisioned above. Thoughts?

And the question is when filling/emptying via the cooler lines, how much o ld fluid is mixing w/the new anyway. Does it really make a difference???

A power flush is supposed to remove ALL old fluid, including what's in the torque converter.

The power flus changes out all the fluid, dropping the pan doesn't. The better solution is to drop the pan, then power flush through the return line so the fluid goes "backwards" through the system. With the pan off the old fluid comes out through the pump pick-up. Then you replace the filter and enjoy the new fluid.

BUT on a trans that hasn't been serviced the entire process is a BIG crap shoot. The reason being that the old fluid has been used up. The additives that help it perform are gone and the mechanicals in the trans are worn. The new fluid goes in and cleans the system, it is also slipperier than the old fluid you usually end up with a trans that soon starts to slip and burns itself up.

On Saturday, October 17, 2015 at 2:15:04 AM UTC+8, snipped-for-privacy@gmail.com wro te:

dipstick with a pump, filter that, put it back in. Then maybe just drop th e pan and change fluid and filter 1 more time. What do you think? That was one thing I love about the Venture, 7.4 quarts spilled out when you dropped the pan. And it has a beautiful reusable ribbed gasket (my 2001 anyway). O ther cars where 1/2 or less of the fluid came out when dropping the pan - I guess you have to use the cooler lines to change the fluid (a quart or so at a time I'm told, by cranking). Or what I envisioned above. Thoughts?

old fluid is mixing w/the new anyway. Does it really make a difference???

Trouble is an automatic transmission has parallel pathways, so to get the o ld stuff out is not so simple. I have a 4L60E (same as in Roadmaster). I have had it flushed a few times. One flush used 17 litres of ATF, whereas the capactity in manuals states 11 litres. The workshop claimed you had to push about 50% extra through to eliminate the old slops.

The new fluids really can go 100K IF you don't abuse the transmission, like with heavy towing over and over again in hot weather. But if it's just a car driving normally they have made the new fluids bulletproof. Old fluids gave up within 15,000 to 30,000 miles, new ones don't.

Research paper here

It compares some of the old favorites to the newer formulations with charts and graphs showing the differences. It's from 1998 and things would have only gotten better since then. My feeling is change the transmission fluid at 75K intervals and you're golden.

Another theory is that the reverse flush forces debris back into little openings it was lucky to get thru the first time and now you are jamming it back in there. The same issue has been raised with the common practice of pushing disk brake pistons back into the bore - that it forces dirty fluid back up into the delicate ABS valve block and mucks it up. New advice is to crack the bleeder when pushing the pistons back to avoid that. I see no reason to flush a transmission.. For the cost of the flush you could just have a regular pan drop and filter done twice as often and not run the risk.

for clarity what I meant above was pull it out through the dipstick a few t imes before the 2nd change. Whatever. 60$ 3x isn't horrible if it keeps it running.

I knew a guy who had a Freestar w/black tranny fluid driven in the metro NY area, around 100k. He changed the fluid 3x in 100 mile intervals. It laste d a few years. He junked the van eventually, but it's a Ford, so what can y ou expect (I know, some Fords last 300k, but that one didn't). It probably died (what specifically I don't know) at 160k about.

Usually it's the clutch packs that go in a tranny. They need slippery oil. I don't understand that being the issue. I do know of A LOT of (GM) cars th ough that never had their fluid changed and last upwards of 200k or more. T his issue seemingly will never be resolved. If it's a new car, I guess the best thing is to change it every 30k just to be safe.

On Monday, October 19, 2015 at 3:49:34 PM UTC-5, snipped-for-privacy@gmail.com wrote :

times before the 2nd change. Whatever. 60$ 3x isn't horrible if it keeps i t running.

NY area, around 100k. He changed the fluid 3x in 100 mile intervals. It las ted a few years. He junked the van eventually, but it's a Ford, so what can you expect (I know, some Fords last 300k, but that one didn't). It probabl y died (what specifically I don't know) at 160k about.

. I don't understand that being the issue. I do know of A LOT of (GM) cars though that never had their fluid changed and last upwards of 200k or more. This issue seemingly will never be resolved. If it's a new car, I guess th e best thing is to change it every 30k just to be safe.

I once had the automatic transmission in my 1973 full size Dodge van rebuil t. One of the things that was worn out was one of the synchronizer rings. I t cost me over $800.00 to have the transmission rebuilt at the Dr. Transmis sion shop near me.

Dodge van rebuilt. One of the things that was worn out was one of the synchronizer rings. It cost me over $800.00 to have the transmission rebuilt at the Dr. Transmission shop near me.

Synchro ring in a 747? Just more and continuing evidence that you're clearly out of your mind.