Transmission shudders

amexjoe · #1 03-18-2007, 08:24 AM

Hi Folks,
It feels like the torque converter lock is slipping and grabbing making the truck shudder. This does not happen when I am getting the truck to cruising speed, but when cruising speed is reached, the shudders start.

I have read in other posts about the TCC and it sounds like this will disable the TC lock. Do I have that right? Will that stop the shuddering at cruising speed?

Thanks in advance.

LMP · #2 03-18-2007, 12:16 PM

Best is to make the test. YOU did not mention year , but I think you have found all info relative to that, so go for it: no cost, no risk.

amexjoe · #3 03-18-2007, 07:36 PM

Here is a giant BOOYA to ya!!!!!
This Trans Sport is a 1996 with 279000 kliks.
I pulled wire "A" from the TCC connector, shudder is history.
It feels like its pulling a nascar, but way better than the shudder.
Hats off to y'all

LMP · #4 03-18-2007, 09:13 PM

Great. From now on, you will have the CEL ON because it will sense incorrect voltage on the wire that is disconnected. THis may occult other alarms that might come from other causes, so reading the codes from time to time will make sure you keep track of what is happening.

amexjoe · #5 03-21-2007, 07:01 AM

The shudder is back!!!! ARGH.
it is oh so slight when the tranys cold but when it gets hot, after about 30 minutes hyway 80-100 kmh, its all a shudderin. Not nearly as bad as the lock going off and on but pretty bad. I bought this puppy used last year in October, so I do not know the history of the trany and engine. Although, the engine ticks maddly until it is warm then calms down.

I could sure use some options as what to do next to fix the shudder.

Thanks in advance

caddy57 · #6 03-22-2007, 10:02 AM

Try the EGR valve, either clean or replace. Mine did the same and went through all you have just to find out the valve was bad. 1996 3.4 237000 miles. Still running strong

amexjoe · #7 03-23-2007, 07:01 AM

Thanks caddy57, the Haynes book does not discuss how to clean an EGR, so a few pointers would be helpfull. Jobber wants 160$ for a new one, ouch!!. How can the EGR be bypassed? Any point in looking in the wrecking yard for a used one?
Thanks
Have a great day!

caddy57 · #8 03-23-2007, 09:21 AM

No chances are they would'nt be any good. It can not be bypassed, but it is located on rear of engine, attatched to the same bolt that holds the trans dipstick in place. 2 othter bolts hold it down. Just take it off and use c arb cleaner on it. Make sure the pintal will move freely

amexjoe · #9 03-23-2007, 01:10 PM

Thanks caddy57,
The egr is out and it looks pretty clean, there is some carbon inside, the only part that moves moves freely, when I shake it, it has a bit of a free play noise. There does not appear to be anyway to take it apart without destroying it, so, do I just spray the carb cleaner all over the inside? Any particular brand of carb cleaner? Is the cheap stuff fine for this application?
thanks

hi ho, hi ho, hi ho,

blazes9395 · #10 03-24-2007, 04:56 PM

The transmission shudder, is likely because something is slipping inside the trans, in this case I would bet its the torque convertor. Did you scan for any SES codes? For a shudder'in tranny, I would reccomend the valvoline ATF DexronIII/Mercon, its avaliable at Walmart up here in Canada(blue bottle/jug) for the cheapest price. Its has a good additive package that specifically helps for shudderin transmissions.

In this case I would drop the pan, replace the filter, clean up /reinstall the pan, fill the tranny with oil, pull off the cooler line coming from the transmission to the rad, add a hose into a bucket start it and dran as much fluid out as possible shut it off, refill and once again do this. The idea here is that your flushing out as much old oil as possible. Refill the tranny, reconnect the cooler line and see what happens. I would also use a Lube Gaurd http://www.lubegard.com/automotive/trans_atf.html, or http://www.lubegard.com/automotive/t...dder_fixx.html

I don't know where you can get Lubegaurd in stores, as I buy it from a tranny parts wharehouse, so I don't know where to send you for this. We use to use this at the shop all the time, it is a good supplement, and does help alot, others may disagree, their choice.

Good Luck

amexjoe · #11 04-03-2007, 08:18 AM

WELL...don't I feel stupid now...
spark plugs and ignition wires, re & re, runs like the day it left the factory. No shudder, tons of power, smooth as silk. Now I can spend the 2k$ on tools.

Thanks to everyone who gave this a kick.

kingarthur2 · #12 04-04-2007, 10:02 AM

Know the feeling. I recently fitted new HT leads to my 3.1 transport and boy-o-boy did it make a huge improvement. The thing takes off nearly as fast as my 3.8 transport gt. Wish I had done this a year ago.

Laura H · #13 01-28-2009, 12:18 AM

I know this is a really old thread, but I've just been searching desperately to try to find out why my 98 Transport van is shuddering and came across this forum. So far, I've changed the oil, replaced the water pump, new plugs and flushed and replaced the transmission fluid. I was optimistic after the transmission flush, the shudder seemed to stop but it was short-lived. A trip to the mainland and up the upper levels hwy had it happening all over again. The guy at Great Canadian Oil Change suggested using that additive but is that just masking a greater problem? There were a few forums that suggested draining the locking torque converter (whatever that is). Does that make sense? I'm hoping to hang on to this van at least until I pay for my daughter's braces, but that's still a year away. My mechanic says not to fix your vehicle on the internet, but so far, he hasn't been able to fix it either. Any suggestions?

LMP · #14 01-28-2009, 08:50 AM

OK...yes, an old thread...but you probably just missed several others that were more recent. A very common problem across several GM forums
Some effort must be taken in the descriptiuon of the "type" of shudder , when it happens (in which gear...probably 4th, after the TOrque converter clutch (TCC) applies, and so on..but you tell). If you need explanation about the vocabulary, please ask.
.."draining the locking torque converter" is about a complete replacement of transmission fluid as some is left trapped in the converter...but this will not change the condition tou experience, and uses a lot of transmission fluid ; you used the word "flushed"..so may be you did it already. What is rather suggested is to disconnect the TCC, not necessarily as the solution but at least as a means to evaluate the condition...but
Read this:
www.avigex.ca/xport/tccshudder.jpg
in the mean time I'll try to find out a few more treads with extra explanation already available....and I'll add the links...
something else here : http://www.automotiveforums.com/vbul...d.php?t=937516

Laura H · #15 01-28-2009, 10:53 AM

Thanks so much for the reply. I checked with the place that did the transmission flush the other day and he said, yes, the torque converter would have been flushed as well. So I guess I can cross that off my list. It seems that I may be wrong in calling it a shudder. He says that a shudder would continue for some time, but what I feel is more like a bump or a thump, almost always at 80K going uphill. It also sometimes happens at around 40K but not always. He has suggested driving in 3rd instead of D to see if it makes a difference but to keep an eye on the rev's. The vehicle runs fine other than this annoying "bump" which I can live with if I knew for sure that it isn't doing any other major damage by driving it. My emergency credit card can't afford a new transmission right now. Thanks for any help or suggestions.

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