tranny problem/no tcu code

craftylandshark · #1 07-20-2006, 12:19 PM

i'm afraid my transmission is on its way out

shifting into and out of second gear is happening WAY too late, and it feels like the clutch is working WAY too hard in that vicinity. no flare, just a late shift. i'm not getting anything from the TCU except the old code from when i unplugged the resistor to see if that helped (as expected, the shift firmed up, but it still came late - somewhere around 3500-4000 rpm under tame city acceleration). My ATF level is fine and the fluid is clean, but the diff fluid is thick, opaque brown and sludgy. (This could be how it's supposed to be, never dealt with diff fluid before, but i doubt it) I'll be draining and changing that later today.

It seems like 2nd is usually one of the first gears to go when our trannies are dying so am I likely looking at a rebuild? My mechanic reccomended a tranny guy - I'm gonna take it by his shop hopefully tomorrow and he's gonna look it over, but if there's a miracle cure for this (riiiiiiiight

), someone please tell me lol

svxfiles · #2 07-20-2006, 02:34 PM

The first thing you should do is adjust your T.P.S.(throttle position sensor) to 0.50 volts with the key on, and everything else off.

seion · #3 07-20-2006, 02:35 PM

Quote:

Originally Posted by craftylandshark

i'm afraid my transmission is on its way out

shifting into and out of second gear is happening WAY too late, and it feels like the clutch is working WAY too hard in that vicinity. no flare, just a late shift. i'm not getting anything from the TCU except the old code from when i unplugged the resistor to see if that helped (as expected, the shift firmed up, but it still came late - somewhere around 3500-4000 rpm under tame city acceleration). My ATF level is fine and the fluid is clean, but the diff fluid is thick, opaque brown and sludgy. (This could be how it's supposed to be, never dealt with diff fluid before, but i doubt it) I'll be draining and changing that later today.

It seems like 2nd is usually one of the first gears to go when our trannies are dying so am I likely looking at a rebuild? My mechanic reccomended a tranny guy - I'm gonna take it by his shop hopefully tomorrow and he's gonna look it over, but if there's a miracle cure for this (riiiiiiiight

), someone please tell me lol

Diff gear oil is yellow and thick when new; change yours now. Adjust your bands as well (do a search for band adjustment).

#4 07-20-2006, 04:39 PM

Hi, I've got a 92 that is doing the same thing, but also will hunt up and down at steady speed and now sometimes it will start in third gear even if the manual button is pushed and stick is in low. fluid looks good and when acting normal - shifts nice. any suggestions ????

thanks

Earthworm · #5 07-20-2006, 05:37 PM

Starting in 3rd is indication of a malfunctioning (or missing) TCU.

Hunting at a steady speed is usually a bad/dirty signal from the TPS (Throttle Position Sensor)

oab_au · #6 07-20-2006, 06:23 PM

Quote:

Originally Posted by svxfiles

The first thing you should do is adjust your T.P.S.(throttle position sensor) to 0.50 volts with the key on, and everything else off.

Yes I agree with the old guy,

.

If the trans is shifting at a higher speed than it should, it is because either, the TCU is seeing the throttle being open wider, than it is. Or it is seeing the road speed as being slower, than it is.

If it was seeing a slower signal from the speed sensor, it would be trying to lock up the Transfer clutch. If it saw both speed sensors as slow, the speedo would read slow also.

The Throttle Position sensor would be giving a higher than normal, voltage reading, as Tom says.

Harvey.

Trevor · #7 07-20-2006, 06:58 PM

Quote:

Originally Posted by oab_au

Yes I agree with the old guy,

.

If the trans is shifting at a higher speed than it should, it is because either, the TCU is seeing the throttle being open wider, than it is. Or it is seeing the road speed as being slower, than it is.

If it was seeing a slower signal from the speed sensor, it would be trying to lock up the Transfer clutch. If it saw both speed sensors as slow, the speedo would read slow also.

The Throttle Position sensor would be giving a higher than normal voltage reading, as Tom says.

Harvey.

Simply setting/checking the TPS voltage at idle will not locate a fault in the TPS potentiometer. This is arranged as a voltage divider and the voltage could go high at an intermediate position. Check the output voltage while moving the sensor through its complete range, if possible using an instrument with a bar graph. The delayed response of a normal meter may not show up a very short intermittent, but with care is still useful and wotrthwhile. The previous post describing a possible "dirty" signal is apt.

svxfiles · #8 07-20-2006, 09:42 PM

Quote:

Originally Posted by oab_au

Yes I agree with the old guy,

.

If the trans is shifting at a higher speed than it should, it is because either, the TCU is seeing the throttle being open wider, than it is. Or it is seeing the road speed as being slower, than it is.

If it was seeing a slower signal from the speed sensor, it would be trying to lock up the Transfer clutch. If it saw both speed sensors as slow, the speedo would read slow also.

The Throttle Position sensor would be giving a higher than normal, voltage reading, as Tom says.

Harvey.

Thanks

Trevor · #9 07-20-2006, 10:25 PM

Quote:

Originally Posted by svxfiles

Thanks

from Harvey for sure. Not to worry, I have kids older than you and get called much worse.

oab_au · #10 07-20-2006, 11:03 PM

Quote:

Originally Posted by Trevor

from Harvey for sure. Not to worry, I have kids older than you and get called much worse.

Well, it was Tom that was complaining about turning 50.

Geezes

if I was that old, I would still be racing bikes.

Harvey.

Trevor · #11 07-20-2006, 11:35 PM

Quote:

Originally Posted by oab_au

Well, it was Tom that was complaining about turning 50.

Geezes

if I was that old, I would still be racing bikes.

Harvey.

With engine

I'd be on a push bike

craftylandshark · #12 07-21-2006, 04:24 PM

thanks all! i changed the diff fluid from the sulfury pits ... from the looks and consistency of it god only knows how long ago it was changed. i read over and looked at the pics of the TPS and Brake Band adjustments and they're honestly beyond my capabilities right now. so the tranny shop has the car, and i passed the information onto them. Trevor - are they likely to know how properly to check the TPS re: your post?

craftylandshark · #13 07-21-2006, 04:26 PM

BTW, has anybody made the Office Space TPS Reports joke yet?

AppStateSVX · #14 07-23-2006, 02:58 PM

Quote:

Originally Posted by craftylandshark

BTW, has anybody made the Office Space TPS Reports joke yet?

yeah, in case you didn't get that Memo......we're putting cover sheets on ALL of the TPS reports now......

Did the diff change fix the problem? I did change the diff fluid once.....guess I kind of forgot to change it again.......sorry

Trevor · #15 07-23-2006, 05:31 PM

[QUOTE=
Trevor - are they likely to know how properly to check the TPS re: your post? [/QUOTE]

I doubt that they would try. The rule is usually, if its faulty or even suspect, fit a new one and charge the customer. Less hassle and more profitable.

What is more, within all trades these days, there are two defined levels of qualification. There are few considered as being at "component level", i.e. who know what is going on inside each black box and can repair the inner components. Check the ads covering employment where this term is often used.

Sad but true and hence the advantages of in many instances, doing it yourself. Also check the how to section, for more detailed advice.