I just bought my TGP and was out taking it for a drive today. I noticed that at WOT the tranny shift very firm. It's too firm! The car feels like it's going to break in two with the 1-2 shift. Under normal driving everything feels good. Do I have a problem or is everyones like this?
After I fully rebuilt my TSTE trans it shifts like that. At part throttle, it shifts nice (sort of firm, but not too much). But, under full throttle it chrips into second--I built it to do that. But the car has been fully repaired/updated (almost all problems fixed, LOTS of new parts), running a TG160 chip, and I just rebuilt the engine as well.
You should be OK. But, You should replace the trans modulator. It determines the shift firmness. In fact, if you pull the vac line off of it and there's any trans fluid in the line, it's bad. It can cause drivability problems too if it's bad, because the engien sucks trans fluid through the line and bruns it. They cost about $20, and the replacements are usually adjustable. Check out my site for info on replacement.
http://www.turboste.com/modulator.html
Jason
Hey, can I add something? Owners of TGPs with hard/harsh shifts at light/part-throttle positions (and at times harsh engagement shifting from P or N into R or D) need to test the Check Valve/Turbo Boost Pressure Relief Valve there at the Modulator! These can fail creating a vacuum leak that causes the Modulator to make the part-throttle shifts too firm. To test, first understand the check valve is also a bleed off valve, in one direction it will hold against a vacuum from the engine vacuum line, in the other direction it will bleed pressure/boost from that same engine vacuum line. So, the port that is open is the Bleed Port/Pressure Exhaust Fitting, the other goes into the tranny Modulator and the other is the signal/source of either vacuum or boost from the upper intake manifold. You want to yank the plastic Check Valve off and check these functions, blocking the port that went to the tranny and blowing through the hole that was feed from the upper intake manifold vacuum line, it should pass air and this is proper. Next suck on that same port, it should hold a vacuum (the ?Check Valve? action of this device), if it leaks, then replace it!!! GM discontinued these years ago (must of sold out of these, not surprised :x ) but Shawn Lin was kind enough to do some research and found another that would work :D , GM part number 14056648 and is only a few bucks, get it!! For those that can?t see this in their mind or on their car then here!:
http://www.turbograndprix.com/VacModChk1.jpg
And YES I very much vote as well to check for tranny fluid at the vacuum line there at the modulator, I just had an owner call me 2 weeks ago with a dead tranny as his modulator was leaking bad enough to suck the tranny dry before he knew what hit him!!
Jeff M
Good point Jeff, I forgot about that!
Seems like you're gathering some nice info on your site, when are you going to get her done? Can't wait!
Jason
Getting close to having some time to devote, I got hordes of stuff I can't wait to do, but am (trying) to hold those over my head till I get more of the meat typed up. The years of Fix-It and such info that owners, pre-owners are looking for/need most of all. Next week I should be hooking up with the printer on those TGP posters, last 2 weeks been sicker than sh-t so doing some catch up right now, been bombed with pipe and chip orders for the last month, seems my statements on the other board must of convinced a lot of people about a reputable background :lol:
Jeff M
Do all TGP have this valve? Unless I'm looking at the wrong thing I don't think my car has one. There is just a straight vacuum line from the modulator to the engine.
Uhhh, then that explains the problem!!! Do this.......tell the dealer who is selling the TGP that your tranny guy told you that the harsh shift is because the the tranny is going out/needs rebuilt, then offer the dealer guy less money for the car!!!
Then when you buy it, get that dang check valve installed like it is supposed to be on all TGPs and TSTEs!!!
Good luck
Jeff M
Well that idea won't really work as I already own the car and I bought it from a private seller. The thing that gets me about this is that the car seems to drive/shift just fine under normal conditions, it's just at WOT that it shifts really hard. Does anyone have an actual picture they can post or e-mail me (4pasnu@seacgp.org) of this check valve so I can verify that I do/do not have it installed. I'm going to take a picture of mine and see if I can post it so you all can comment.
I can confirm what has been posted. My 1990 TGP would SOMETIMES have a very hard part throttle shifts (enough to make the dash plastic creak) and coming to a stop at 8 MPH it would downshift into 1st so hard that it would startle passengers. Unfortunately I could not solve this and it probably damaged my tranny as I drove about 5000-7000 miles with this problem!!
It turned out I needed to use the new plastic check valve just as Jeff M has posted and it solved all my problems. The funny part is I already had bought the new check valve a long time ago and I had it sitting on my shelf thinking I didn't need it (I bought it to fix another problem with my tranny but it didnt solve that so I hadn't ended up using it.)
Finally I will say my original check valve did not seem to test out any different than the new one when I blew with my mouth! So if your car is having the clunking just go ahead and try replacing the check valve anyway , its like a 3 dollar part and easily worth a try since it takes 30 seconds to swap.
Quote from: 4PASNUWell that idea won't really work as I already own the car and I bought it from a private seller. The thing that gets me about this is that the car seems to drive/shift just fine under normal conditions, it's just at WOT that it shifts really hard. Does anyone have an actual picture they can post or e-mail me (4pasnu@seacgp.org) of this check valve so I can verify that I do/do not have it installed. I'm going to take a picture of mine and see if I can post it so you all can comment.
DUDE, pay attention!!! In my post above there is a link to the pic you want/THE CHECK VALVE!! :silly: Click on the link, see the pic, be the pic, do the pic!! :headbang:
Jeff M
Quote from: TookyCatand coming to a stop at 8 MPH it would downshift into 1st so hard that it would startle passengers.
Mine used to do the same thing. After I replaced the dogbones it quit doing it. When I took the old ones off the rubber bushings fell out on the ground. :drinking:
No need to be rude now. I did see the link and I did look at the picture but if you were paying attention and read my post I would like to see an ACTUAL picture, not just a drawing! Please remember that I'm new to the whole TGP scene and I'm just looking for a little friendly help. Thanks.
Here is a link to a picture of what the new ACDelco check valve will look like. Your old one should be similar but beige in color (at least mine was).
http://www.rockauto.com/ref/ACDelco/Detail.html?14056648.jpg
I don't think Jeff was being rude. Its soooo hard to get tone in a post. Notice the funky smilies? If not for them I guess it would have seemed rude, but I know Jeff and he was just trying to be light about it.
However, he did say an ACTUAL picture....
(http://aldridgec.home.att.net/images/Transmission/chkvlv.jpg)
And here is where it goes....
(http://aldridgec.home.att.net/images/Transmission/chkvlv2.jpg)
Chris
4pasnu, no one (me) is picking on you, that is why I used a few cool funny face emocons :D :D :D when I was getting after you/funning with you! Though its not easy to "hear" the tone of my voice to know if I am yelling or razzing you, those emocons work great at helping in that sence, and my "see the pic, be the pic do the pic" and headbanger guy was funny/funnin with you!!
As for the pic or drawing, it sounds as if you don't have the item on your car and since you need it, when you buy it you will see what it looks like :P And the drawing is the way in must be installed, harder to tell in a photo with the lighting and such. You can still ask for a pic, someone might have a good pic, I don't but I am not the only guy on here 8)
So, welcome aboard, we have fun here while we work/help each other so know now that we will give you some harrassing from time to time, not disrepect, and you can do the same right back, we like it long as its in good taste :drinking:
And, we like helping and even though its not nessisary, give those who help you a nod (like tookycat and Chris A, they got your pic!!) once in a while, little recognition for our efforts is nice, we get too many that dine-and-dash, suck our brains then never return with how our help worked out, or help someone else who comes with a problem, you will get the hang of things here, just give people the benifit of the doubt, most all here will go to great lengths to help, and slap you around in a good sort of way :) !
Jeff M
Thank you so much Chris A for the picture. Nope I don't have it so I guess I'm going to have to get one!! Is GMpartsdirect the best place to go to get it? I refuse to go to my local dealer. I had a bit of a falling out with them and I vowed never to return.
Jeff M, sorry about that. I guess I should have got that since you did use the Emoticons. Just to ease your mind, I'm not one to "dine and dash" as you put it. I'm here to stay. I love this car and I've only had it a few days. Thanks again for the help guys.
It costs $2 - $3 from GMPartsDirect but shipping takes the cost to around $10. A little too much if you ask me.
If it will save my tranny, $10 is a deal!
Quote from: 4PASNUThank you so much Chris A for the picture. Nope I don't have it so I guess I'm going to have to get one!! Is GMpartsdirect the best place to go to get it? I refuse to go to my local dealer. I had a bit of a falling out with them and I vowed never to return.
Jeff M, sorry about that. I guess I should have got that since you did use the Emoticons. Just to ease your mind, I'm not one to "dine and dash" as you put it. I'm here to stay. I love this car and I've only had it a few days. Thanks again for the help guys.
Chris is awesome, but humble like me so he won't like me bragging about him :lol: Chris is very correct, GMpartsdirect kills on shipping and handling costs, they bait you with their wholesale then blow it all away when they tell you
only on the
next "purchase" screen that the S&H is major bucks!! The common to fail crossover pipe retail is $1,441.62 and their price is $821 BUTTTTT their Shipping and Handling is $164!!! I can ship Same-Day for that much, NextDay to most states here in the USA for around $25 to $35, their nuts but that is how they make thier money so unless you have a dealer discount account setup, no other way to get it cheaper than retail.
As for my words to you before, no problem, we only get after those in their behalf to get thier cars fixed, once you have been here a while, you will find there are many guys who really know thier stuff and you just do what they say and you will be all set, for SURE ask to explain if you want as we like to explain why, but bottom line is their help if what needs to be done. AND since I missed that you did not have harsh shift at part throttle :oops: but only at full or near full throttle, then for sure, the check valve is what you need to fix that. Maybe you have another local dealer, it does not have to be a Pontiac Dealer, any GM Dealer can get that part, or any other GM part you need! As for being a dine and dash, it was a general statement made to explain how us who have been on here a long time, can be a little touchy at commiting a ton of time, not that you are one of these, it just explains some of what us old guys have learned to look out for and how it may change the way we reply to people. I have seen you posting/helping on other areas here so it does not apply to you.
Good luck.
Jeff M
Quote from: Jeff MChris is very correct, GMpartsdirect kills on shipping and handling costs, they bait you with their wholesale then blow it all away when they tell you only on the next "purchase" screen that the S&H is major bucks!!
It was redturbo90 actually, just don't want to take credit for pointing out how GMParts direct bends you. 8)
The picutre that someone showed before from AC Delco is actually a common used accesory check valve (goes between the manifold vacuum and the car accesories like cruise and heater). It should probably work the same. Good thing is though, many parts stores carry this part in their "Help" section. So in the meantime, you can try there to see if they have it. I'm not sure if its function is any different than the original valve, but it should work all the same.
Chris
Quote from: Jeff MGetting close to having some time to devote, I got hordes of stuff I can't wait to do, but am (trying) to hold those over my head till I get more of the meat typed up. The years of Fix-It and such info that owners, pre-owners are looking for/need most of all. Next week I should be hooking up with the printer on those TGP posters, last 2 weeks been sicker than sh-t so doing some catch up right now, been bombed with pipe and chip orders for the last month, seems my statements on the other board must of convinced a lot of people about a reputable background :lol:
Jeff M
I'm sure they have. I love your chip, works excellent! And I can't wait till it gets nicer out so I can visit. The digital camera will be ready!!
I want one of those posters! How much are they going to cost (estimate)?
Jason
Eclips5302/Jason, first thanks for being the one to mention GMPartsDirect, missed that as I was rushing to keep on top of this topic :oops:
As for the rest. Thanks on the chips, I am a picky bugger about my stuff :-). And looking forward to that visit, by then I will have my TSTE and/or TGP in stages of power testing with bigger turbos, bigger injectors for that turbo, bigger intercooler and anything else that looks worth investigating. This year will be the best for me when everything I have been working on, along with these last tests, will all be done, and so all those who have been patiently waiting will be greatly rewarded. And like the poster, which I am expecting to sell for around $30 or less if I can (will find out next week on the end costs), these upgraded kits will also be as cheap (cost) as I can make them so more owners can step up to plate and make a home run, or at least a ? time worth bragging about!!! Or like the 350 hp TGP turbo, I don't want to add even $25 for my time in getting these figuered out and a chip to work with them (though I will charge for the chip), I will just tell people the specs as I just want to see people get these (for those that want it) and really enjoy the go-pedal!!!
Well, its 3am but I am going to continue my typing up the pages and pages of fixes I have gathered up over the last 13 years, looking to make my web site something worth visiting!!!
Jeff M
So I have the part number for the valve, now does anyone know the part number for the modulator that was mentioned earlier in the post? Also, what about the transmission part number? I'm going to be doing a GMpartsdirect order and just trying to get everything in order before I do. Thanks.
You should go with an aftermarket modulator. They are usually adjustable, and thats a nice thing to have with the TGP trans. They can be had from summit or jegs.
Jason
I replaced mine and it still shifts hard. :x Ugh , I forgot I got mine rebuilt at Aamco :bag:
I looked up "transmission modulator" on Summit's web site and it came up with the part number SUM-G110. It looks like the right one but could someone look at it and tell me if this is what I need? Also, I meant to ask for the transmission filter part number above, no the actual transmission part number, anyone know it?
there is no need to buy the adjustable at any other place than the local parts store!!!!!!!!! They cost $7.00 at advanceautoparts. If for some reason you look in the box and its not adjustable just ask for a modulator for a 77 camaro with a 350 :D!
(http://store.summitracing.com/global/images/prod/large/sum-g110.jpg) yes this modulator from summit is the same one but its $5 more dollars and has shipping :(