What causes shuddering in the transmission

[Gummel]

What causes shuddering in the transmission when shifting? I am trying to figure out what is going bad the TC, VB or what? I am getting this shuddering after shifting to OD. I am going to turn up the line pressure this weekend but I want to be prepared for what is going to break. The transmission has been well maintained fluid/filter change after 30,000 or so. Maybe there is something that I can fix to avoid ruining the transmission. Also is there a good transmission shop in NH or close by?

I will soon be stepping up to a #6 plate, 3000 governor spring and AFC spring.

What should I do?

 

[Extreme1]

If you are refering to the shaking that happens under light acceleration right after lock-up, they all do that. The same thing happens in mine from about 43 (lock-up) to 48 mph. It is the engine lugging. Why did DC design it to do that?

 

[jhnbrll]

gummel my dodge has done that since I bought it. Ive changed the sbec and that didn't help it and no one knows how to correct it. I had my transmission rebuilt by blue chip in hudson NH. I was real happy with the work. you can find him at hope this helps.

 

[Gummel]

Jburelle thank you for the info! At Blue chip what was the cost for a rebuild and did you have any extras done to it? How long did you let the shudder go on before the rebuild?

Micah

Oo.

 

[jhnbrll]

Blue chip rebuilt the transmission, installed the #16 turbo housing, and installed the banks pyrometer and boost gauges. now my truck is a 94 and at the time had 150,000 miles and the transmission was slipping real bad so he had to rebuild the whole thing with all new parts. I don't remember exactly, but it was all about $5000. At the time I was real nervous about putting that amunt of money into this truck, but now I hae 180,000+ miles pulling a 10,000 lb trailer and its held up real well. yes it is a lot of money but I couldn't afford to buy a new truck so this was the next best thing and it paid off for me I feel. But of coarse I only paid $12,000 for the truck. now as for the shudder, it only shudders when the truck is in od and I slow down to 45 mph. when I had the transmission rebuilt alan ( who works for blue chip) said that the shuddering was caused by the engine controller or the sbec and that needs to be replaced so I did. It still shudders but not as bad. so my corrective action at this time is to not drive at 45 mph or if I have to I just take it out of od and its fine. As for blue chip yes he is a little pricy but I think it was worth it. Oh I almost forgot part of tha price was for the high pressure lines and steel planetary gears as opposed to the aluminum for plowing snow. ( his recommendation) well I hope this helps you and good luck. also I think his price list is on his web site.

 

[BHaner]

sbec

What is it, what does it do, do i have one in a 97 auto, and if so where is it.



I have this exact problem in my truck. BD says it's not the trany but is the same as lugging a 5 speed down too far. I would really like to make it go away. Sometimes it's so violent that it spills my drink in the holder.

 

[illflem]

The solution is extremely simple, push the OD off button below 50 mph.

 

[BHaner]

50 mph

The only problem is 90% of my driving is at 50 mph. If i run out of overdrive i only get 12-13 mpg. In OD I get 15-16. Guess i will just need to live with it.

 

[pathaymond]

Just hit the button and take her out of overdrive you may burn more fuel but In my opinion its much better for all the systems. I have 355 rears and I am only in overdrive when my rpms are into the 2K area and will remain there I take my foot out a bit hit the button and let the machine shift. I had a 93 5 speed treated it the same way never saw fifth until higher rpms that beast saw 545k never ever touched anything same clutch etc. Good luck Patrick

 

[Gummel]

Yeah, but what is the cause of this shaking during acceleration after shifting in to OD!

Thank, for the advice so far but somebody has the answer to this. I know you are out there!!

Oo. Oo. Oo. Oo.

 

[jhnbrll]

the sbec is as I understood it, the engine controller. it reads the rpms in the engine and tell the transmission when to shift. thats the way it was explained to me. if I'm wrong someone telll me. i don't know maybe I got another bad controller. I know when I changed it wasn't as bad. the sbec is the large black box with the big plug in it located on the fire wall right behind the air cleaner. I am curious about this 3k spring does it really give you more power. is it worth it?

 

[Strick-9]

My transmission doesn't buck as you guys describe. I wouldn't say it was normal. Spilling coffee in the drink holder is NOT normal.



Does it buck regardless of throttle position at those speeds or is it only at light throttle, low rpm, converter locked?



-Chris

 

[pathaymond]

I wish I had another answer for you sir. I am new to the auto world and what you describe sounds like lugging a five speed badly. . I bet the box the others speak of is or could be the problem I plan to watch this post for future reference. I am sure the ddt peaple have the right answer for you. . Good luck Patrick

 

[illflem]

Originally posted by Gummel

Yeah, but what is the cause of this shaking during acceleration after shifting in to OD!

Thank, for the advice so far but somebody has the answer to this. I know you are out there!!

It's just as others have said, similar to lugging in 5th gear. If you accelerate slowly the problem will be worse because the OD engages at a lower mph. Bill K of DTT has said here many times OD should engage at 50-55 mph. It is adjustable and has been explained here many times but I've never paid much attention and can't tell you how.

 

[Steve Roseman]

lockup shudder

Try installing a switch to unlock converter. You shoudn't get any shudder with the factory converter if the lockup is off.

Be sure to install a transmission temp gauge so you can monitor temps while unlocked.

 

[lhend50]

I had a similar problem this vacation when towing a 13000 5th wheel from NJ to Georgia. I have 80,000 on the truck and never had it shudder. It happened at about 70mph in od and on cruise. It only happened as I would crest a hill. It pulled the hill fine with no lugging, but when I got to the top it would shudder. If I came off of cruise I had no problem. It only did it a couple of times. Is this a different type of problem.

Thanks

Lou

 

[MChoquette]

Gummel ,1996 and up sbec can be reflashed programed so the coverter will lock up at 53 mph . Cost should be @ $50. 00 or what ever is the dealers hourly rate. As for pre 96 models , you need to buy a new updated version of the sbec. Cost @ $150. 00 and up for a remaned unit. Good luck.

 

[Steve Roseman]

My 95 was reflashed to lockup at 53mph. I'm pretty sure 94-96 is the same, they use the same transmission. I still use the switch to keep it unlocked until rpm's are higher and boost is under 10 lbs.

 

[BHaner]

reply to Stick-9

Only does it under light pressure in lockup from 45(lockup) to 52. Most of the time when I come back down from about 1/3 throttle. Never does it when I am over 1/3. I was thinking it was something to do with my fuel pressure being too low. I need it tested or to install a gauge to be sure. I have AutoMeter Ultra Lites... . do they make a fuel pressure gauge? How are you guys hooking it up in these 12 valves?



Thanks for your help!

 

[TURBOs4LIFE]

Lock up shudder

Mine just started doing it this winter! How long will a torque converter last if it shudders like this? Mine will shudder at slower speeds and when I speed up all of the sudden. Will it get worse over a period of time? I want to have it reflashed to 53 mph for lock up but was wondering if I should get the converter replaced first. THANKS