HELP!! Tranny shifting problem on 1991 Roadster!!

[3DFLYER]

What could it be??? Tranny question.

I was driving along and was coming to a stop a few days ago and decided to physically downshift my automatic tranny to second gear. I was expecting it to shift, but got nothing!!

I noticed when accelerating again the tranny seemed to shift through all the gears with no problem, just a little slower between shifts than I remember.

The car has 120K on it and I believe it's the original tranny and has had NO major repairs yet.

Anyone else had this happen??? What did you find to be the problem???

I don't notice any gear slippage, but don't know what else to look at. I was told that by my description, the pressure build up in the tranny is getting weak and is probably the cause.

Help/advice would be appreciated.

Tom

 

[BlackNBlue95]

I'm a little confused.. you came to a stop and then put it into 2nd gear? it would start off in 1st at that point and then as you accelerate shift into second.. Please explain again what the vehicle was doing and what gear the shifter was in..
-Rick

 

[vigman]

3D What speed were you at?

2nd..DO NOT GET A TRANNY FLUSH! I'll put a post up on that..but just get a regular service....$70.00 ish bucks they will drop the pan drain 5 qts change the filter.. and inspect the GOOK in the bottom of your pan.. that will tell more of the story!

You are probably getting varnish built up in the valves that control shifting!

I'll find the post ...BRB

Vig!

 

[vigman]

Something for you to read!

The tranny flush debate....It's Long..but you will get A LOT out of reading it!

http://corvetteactioncenter.com/forums/showthread.php?s=&threadid=8671&highlight=Flush


Vig!~

 

[BlackNBlue95]

On the Subject of Trans Flushes:
I perform usualy 1-4 a day at my shop.. I reccomend doing a flush then a pan off with filter alternating every 10 or 20K miles NOW I believe you should not do a flush if the fluid has not been changed for ~40K miles because the trans fluid breaks down and the detergents in it no longer suspend the dirt particals from the frictions and all.. and what happens is the particals build up around the seals and now help to reshape the seal it's kind ahard to explain with out drawing a picture of the lip seal and then the lip seal with the gunk buildup.. but then anyhow you flush the 40K mile+ trans and you clean all the gunk out of it ok now the seals start to leak because the gunk is no longer there to help them seal what happens is the seal gets reformed to accomodate the gunk film on the walls of the piston bore.. so now that the gunk is gone the fluid can pass by the seals.. I know this first hand my trans failed shortly after I flushed it at 40K miles.. and I rebuilt it myself..

but I would like to know more about this problem so we can try to figure out the cause of it.. if it has 120K miles on it it may be living on borrowed time anyway am you may be looking at a trans rebuild but I would just wait to see if we can solve or figure out what is causing the issue at hand first..
-Rick

 

[vigman]

Ok a flush with a pan removal is better...BUT

You stated it yourself... the gunk ( varnish ) that was making the seals work is now gone.

All I'm stating is with a HIGH MILAGE tranny, that hasn't been serviced regulary.

And the fluid is BROWN....

IF you power flush..you are signing a death warrant for that tranny... where you probably could milk it along LONGER..if you just do a filter change & 5 or so quarts.. this will remove
SOME of the varnish & debris..but not enough to make it... slipper/ dripper.

I agree that a full rebuild is the ticket.. to do the job correctly!

Vig!

 

[BlackNBlue95]

Re: Ok a flush with a pan removal is better...BUT

You stated it yourself... the gunk ( varnish ) that was making the seals work is now gone.

All I'm stating is with a HIGH MILAGE tranny, that hasn't been serviced regulary.

And the fluid is BROWN....

IF you power flush..you are signing a death warrant for that tranny... where you probably could milk it along LONGER..if you just do a filter change & 5 or so quarts.. this will remove
SOME of the varnish & debris..but not enough to make it... slipper/ dripper.

I agree that a full rebuild is the ticket.. to do the job correctly!

Vig!

Couldn't agree more don't flush a high mileage never serviced tranny..

Power flush? I like that term.. I'm wondering is there a machine out there that uses sometype of external pressure to flush.. just curious how that would work.. the machince I use is a BG setup that basically has a tank with a bladder in it.. I fill it with 16qts of Fresh AFT and hook it up to the trans cooler like and as the trans pumps the old fluid out of the trans the new fluid on the opposite side of the bladder is pushed in with the same pressure as the trans cooler output.. We also put a cleaner in the trans before we flush then when were done with poor in a conditioner which helps keep the seals soft.. it's a pretty simple and is a great profit lever for our shop even though I make ~11 or 12 bucks out of the job and we charge like 125$ and out of that the labor is like 75$+ so I get kinda screwed on that.. anyway thats off the subject at some point I'll start my own business and be a little more fair and make more profit for myself or in other words make the corrilation between my work output determine my paycheck a little more accurately..

Technicians should be compisated better and have more respect it's not an easy career.. most people can't diagnosis problems let alone fix them.. usually they end up replacing good parts during their efforts.. and may never even fix the problem... though I must say CAC is a very good resource to have available since we all can discuss our auto problems with others which can help us all diagnose and repair our own vehicles or point you in a direction to someone else who can do it for you.. anyway I'm totalt off subject time for me to get to bed so I can wake up and through a fuel tank back into a bus.. LoL.. mini bus..
-Rick