trans question

Bonestock · #1 02-02-2010, 07:08 PM

Am I the only one that the following happens to?

Low speeds (like 20mph school zone) traveling at a steady throttle position and in D. RPM is around 1900ish... all of a sudden the engine will rev to 3k+. I dont seem to accelerate, its more like the trans is slipping. If I let off it goes back to normal.

The car accelerates normally at WOT, from a standing start or passing. The above situation is the ONLY time I have noticed the "problem".

is this normal behavior for a SVX? I was going to see if it does the same thing tomorrow with the trans in 3rd.

Blacky · #2 02-02-2010, 07:13 PM

It's not normal. Your transmission is on it's way out sorry to say.

K_Dub · #3 02-02-2010, 07:19 PM

Is it slipping, or kicking down into a lower gear? If slipping is your symptom, then I hope somebody else jumps in. If it is indeed dropping down to a lower gear then you might want to check your TPS. Mine had similar symptoms, although at a different speed but similar RPM, when the car thought I was flooring it but I was barely pressing down on the gas pedal. Turns out there was a bad spot on my TPS; at WOT it was reading proper, but at low throttle it was way off. Test procedures are in the How-To documents.

I might be wrong here, but testing the TPS was easy and might be worth ruling out.

oab_au · #4 02-02-2010, 07:28 PM

Quote:

Originally Posted by Bonestock

Am I the only one that the following happens to?

Low speeds (like 20mph school zone) traveling at a steady throttle position and in D. RPM is around 1900ish... all of a sudden the engine will rev to 3k+. I dont seem to accelerate, its more like the trans is slipping. If I let off it goes back to normal.

The car accelerates normally at WOT, from a standing start or passing. The above situation is the ONLY time I have noticed the "problem".

is this normal behavior for a SVX? I was going to see if it does the same thing tomorrow with the trans in 3rd.

I would say it is the brake band slipping, to go back to 3rd.

Quote:

Low speeds (like 20mph school zone) traveling at a steady throttle position and in D. RPM is around 1900ish

It is because of the high gearing and the low pump speed that there is not enough pressure to hold the band on. If it does not do it in 3rd, that is the problem. Get one of Svxfiles resistors to raise the pressure, it may prolong the life of it, and don't drive it in 4th at low speeds use 3rd.

Harvey.

Bonestock · #5 02-02-2010, 07:53 PM

Quote:

Originally Posted by oab_au

I would say it is the brake band slipping, to go back to 3rd.

It is because of the high gearing and the low pump speed that there is not enough pressure to hold the band on. If it does not do it in 3rd, that is the problem. Get one of Svxfiles resistors to raise the pressure, it may prolong the life of it, and don't drive it in 4th at low speeds use 3rd.

Harvey.

That is EXACTLY the conclusion my friend and I came up with... a drop in pressure. Will run some tests tomorrow and report back.

trophy956 · #6 02-02-2010, 08:04 PM

hi id check the TPS also ,before i made mine a 5sp i would drive with the select monitor on my car because the trans would do funny things ,the tps voltage would change even though i was not depressing the throttle more ,it was better after the tps was replaced ,but the trans still died ,because the tcm is looking at tps for shifts ,its a cheap place to start,but you still could have bad trans
charlie

Trevor · #7 02-02-2010, 08:09 PM

Your problem indicates low line pressure. The fix should not be expensive and may only involve solenoid valve “A”, which can be replaced without removing the transmission.

In order to properly diagnose the fault, have the line pressure tested. Do not accept an excuse that this is not required and advice that the tranny is stuffed. Your money is the goal.

Do not mess with the resistor and proceed to use the car. The specific purpose of the resistor circuit, is to protect the “A” solenoid. if you require detailed information in thus regard, I will be pleased to oblige.

Yes, meantime drive in third gear. I always religiously do so round town, no matter what, for obvious reasons.

Bonestock · #8 02-02-2010, 08:27 PM

I have been reading your posts Trevor. Please by all means, educate me! As I stated in my first post on this forum, I am ASE Master Certified and I-Car Gold certified but I can and will shut up and listen to anyone that is willing to teach me about a vehicle I have no experience with.

The resistor, is it ok to unplug for testing to verify the shift firmness & speed will increase?

I am not a transmission specialist but I am sure my friend Rob has a line pressure guage.

Trevor · #9 02-02-2010, 10:10 PM

Quote:

Originally Posted by Bonestock

I have been reading your posts Trevor. Please by all means, educate me! As I stated in my first post on this forum, I am ASE Master Certified and I-Car Gold certified but I can and will shut up and listen to anyone that is willing to teach me about a vehicle I have no experience with.

The resistor, is it ok to unplug for testing to verify the shift firmness & speed will increase?

I am not a transmission specialist but I am sure my friend Rob has a line pressure guage.

I do not appreciate your somewhat sarcastic post.

I did not see your first post in this forum.

I was not aware of your credentials.

Your credentials are impressive.

My effort to assist was directed into cyberspace. You have my true name but I do not have yours.

I have never asked you to shut up.

I tried to help you.

It is obvious that it is ok to unplug the resistor for testing.

It is strange that this was not obvious to one so highly credited.

It is bad English to end a sentence with a preposition.

It is not my intention to be a smart arse, I deal only with fact.

bcpianoman · #10 02-02-2010, 10:30 PM

Hi Trevor:

I've admired your efforts to help others for a long time and I've learned a lot from you over the years. For that I thank you.

Now I'm about to stick my nose in your business and I hope you take no offense. I just read the Bonestock thread and I see that you took offense. For what it's worth, I don't know Bonestock at all. I interpreted his post a little different from you though. I thought he was genuine in this request for your help and was setting out his credentials so that you would have an idea of how simple/complex to make your response. That's how I read it anyway - . . . for what it's worth.

Interpreting the intent of posts is often difficult because you can't hear the tone.

Again - I hope I've caused no offense.

Bonestock · #11 02-02-2010, 10:34 PM

Mate you took my post all wrong. I did not intend, nor was it my desire to insult you or be sarcastic by any means.

I genuinely meant what I said. I have NO PROBLEM with someone teaching me about a car even though I am a mechanic myself. Some guys (as I am sure you know) think they know everything and will try to BS their way around a subject or absolutely refuse assistance because they cant set their pride aside. I am not one of those people.

So if I came across as snide, this is me publicly saying I am sorry. I did not mean to.

Otherwise I appreciate your assistance but there is no need to retaliate in the manner that you did. Sorry for the grammar, I did not know I was being graded as such.

Trevor · #12 02-02-2010, 11:02 PM

Quote:

Originally Posted by Bonestock

Mate you took my post all wrong. I did not intend, nor was it my desire to insult you or be sarcastic by any means.

I genuinely meant what I said. I have NO PROBLEM with someone teaching me about a car even though I am a mechanic myself. Some guys (as I am sure you know) think they know everything and will try to BS their way around a subject or absolutely refuse assistance because they cant set their pride aside. I am not one of those people.

So if I came across as snide, this is me publicly saying I am sorry. I did not mean to.

Otherwise I appreciate your assistance but there is no need to retaliate in the manner that you did. Sorry for the grammar, I did not know I was being graded as such.

I sincerely apologise. I got the wrong end of the stick.

Here, I have had so much muck thrown my way of late, that I was quick on the draw. You copped it, sorry.

Sincerely Trevor.

Bonestock · #13 02-03-2010, 04:43 AM

Ok then, on my way out this morning I am going to run the car as normal but in the school zones I am going to selected 3rd. If the problem occurs I am going to unplug the resistor and try again.

I'll break out the DMM and test the TPS as well.

I'll report back later.

dcarrb · #14 02-03-2010, 05:31 AM

Quote:

Originally Posted by K_Dub

I might be wrong here, but testing the TPS was easy and might be worth ruling out.

Second that. My car was gear-hunting (I never sensed this was "slipping," tho'), only at constant throttle in a certain RPM range. A new TPS eliminated the problem. I've always felt this car was shunned because the previous owner and potential buyers feared the transmission was on the way out. In fact, in the trunk I found a Chilton's manual with page markers in the transmission section.

dcb

Bonestock · #15 02-03-2010, 01:42 PM

Well I tested it in 3rd this morning and sure enough it "hung" between gears. On my way home today I unplugged the resistor and it didn't hang at all. Shifted quite nicely, actually.

So, now what?