This is on my stock tranny (4L60E) in an 02 envoy, I was taking my tandem axle 14' trailer (about 1300 lbs) for it's annual inspection and I felt a shudder under load. I'm almost positive the TC was locked in OD...about 50-55 MPH....usually is.I was accelerating and when I was between 1/3-1/2 throttle, TC remained locked and the vehicle started to shudder but was progressive and not a hard shudder but almost felt like a bad U-joint. When I apply the gas at 50 ish, there is no shudder but when I hold the throttle position the shudder comes in lightly then amplifies and goes away when I let off.There is no spike in RPM like a clutch pack slipping but I don't know...shifts fine and runs fine the rest of the time.I have replaced the separator plate, 1-2 and 2-3 acc pistons and have the vette servo. Trans has 182K miles and fluid looks great, replaced 10K miles ago.Fluid has always been replaced at 30-40K intervalsRear was changed from factory 8.0" to a 9.5" SF and I just switched to Redline Heavy Shockproof fluid.U-Joints are new and driveshaft was shortened and balanced.Just curious if this could be a trans issue or not and if so where to look.

this could be it, but maybe the TT tongue weight is causing the axle to bend backwards and the angle of the drive shaft is a little higher thus causing the stutter you describe.

Possibly the torque converter lock up is slipping.BTC

My guess is the driveshaft. It is the only non stock item and logically the first place to look. Having sold and installed a lot of rebuilt driveshafts over the years I have had shakes from initial installation to various times and mileages after installation. Issues have ranged from the yokes being slightly out of phase to my supplier trying a slightly cheaper u-joint in an attempt to improve his bottom line. It could also being something new like the rear main loosening up and the crank is flexing. There are lots of possibilities. At the mileage you have mentioned I would buy a new vrhicle instead of throwing money at a possibly hard to locate shake. Randy

the shorter the drive shaft becomes , the possibility of a driveline shudder increases . The degree of angle of the output shaft needs to be VERY close to the same angle of the pinion shaft on the rear end. This can be done using an inexpensive angle gauge from the home depot or other places . If the truck has leaf springs in the rear the angle of the pinion can fairly easily be changed with the use of simple wedges available through e-bay , amazon or parts houses,placed between the axle mounting plate and the leaf spring.I had the same problem with a Jeep Cherokee that came from the factory doing this and was finally fixed by myself when I learned of this procedure Good luck,

dannydimitt wrote:the shorter the drive shaft becomes , the possibility of a driveline shudder increases . The degree of angle of the output shaft needs to be VERY close to the same angle of the pinion shaft on the rear end. This can be done using an inexpensive angle gauge from the home depot or other places . If the truck has leaf springs in the rear the angle of the pinion can fairly easily be changed with the use of simple wedges available through e-bay , amazon or parts houses,placed between the axle mounting plate and the leaf spring.I had the same problem with a Jeep Cherokee that came from the factory doing this and was finally fixed by myself when I learned of this procedure Good luck,Here is the part # for the angle finder I used Swanson tools part # AF006M

What would cause a shudder under load | Good Sam Community

16 Replies

gmcman
Explorer
Mar 23, 2014
Just wanted to point out to anyone with the 4L60E.... the TCC eliminator, vette servo, and new separator plate which I bought from dealer (plate) really transforms this trans. I am also going to add the Sonnax super hold servo for the 3-4 clutch and wish I did at the time of the vette servo install just to save labor but not a huge deal.

In stock form it's nice and plush but even with the upgrades it's not remotely harsh. I had a 2-3 flare at 166K and the new plate and vette servo have been working fine since then and I am currently at 198K....no flare.
down_home
Explorer II
Mar 23, 2014
gmcman wrote:
randallb wrote:
At the mileage you have mentioned I would buy a new vrhicle instead of throwing money at a possibly hard to locate shake.
Randy

Can't do it..been too good to me....still has a lot of life left, hopefully anyway. I wanted to think the driveshaft was the culprit but why would it shudder when the torque application was at it's lowest? Not exactly the lowest but at the given speed and RPM, no shudder in the lower gears.

The driveshaft was shortened 1.5 inches, U-Joints are of high quality. When I pick the trailer up I will confirm whether or not it was at TC lock but I'm 99% sure it was.

I did speak to someone who is well versed in these tranny's and he believes the TC clutch was the cause. Given the mileage it may just be starting to show it's face and there is a fix for it. Could be the TCC solenoid but more likely adding more fluid to the clutch generally fixes this problem by enlarging the TCC isolator valve bore? I believe that's what it was.

deleted. you already figured it out andI didn't read that post ahead of posting reply.
gmcman
Explorer
Mar 23, 2014
I'm sorry I didn't follow up to this after I removed the PWM TCC control from the ECM.

Since I have changed the valve which removes the computer-controlled lockup to a full on or full off of the TCC, there has been no shudder.

I very much prefer this type of lockup for the TCC and highly recommend the mod, not harsh at all and you know exactly when lockup occurs.
Aqua-Andy
Explorer
Apr 08, 2013
I would say the TCC is slipping. While the problem is happening lightly ride the brake pedal, not to apply the brakes jut enough so the TCC turns off you should see the RPMs go up slightly. If the problem goes away you have a TCC issue.
gmcman
Explorer
Apr 05, 2013
bartlettj wrote:
When was the last time you changed your spark plugs and wires? This may be an engine misfire and not necessarily a transmission problem.

No wires, coil on plug, plugs are new...maybe 1K Miles.

Cloud Dancer wrote:
Does the operator's manual say to NOT tow in overdrive?

No, manual states you can tow in OD.

Driveshaft looks good, plenty of room to move forward. I pick up the trailer tomorrow so I will test the lockup again. I have a TCC valve on it's way so I am going to do away with the PWM control and change it to an on/off lockup. Apparently this is a common mod.
Cloud_Dancer
Explorer II
Apr 02, 2013
Does the operator's manual say to NOT tow in overdrive?
bartlettj
Explorer
Apr 01, 2013
When was the last time you changed your spark plugs and wires? This may be an engine misfire and not necessarily a transmission problem.

If you still think it is the trans shuddering, hook up a gauge and monitor the line pressure. It should fluctuate along with the shudder if it is in the transmission.
gmcman
Explorer
Apr 01, 2013
Good point and I will triple check it tomorrow. I'm almost certain the yoke was at the same position but I will check again to be sure.
sljkansas
Explorer
Apr 01, 2013
I had a Bronco II that had a drive shaft shutter and it happen to be the slip yoke on the front of the drive shaft was worn (not the U-joint). unfortunately I had to replace the complete drive shaft, due to the way it was made.

Your cut down drive shaft may be still too long and is bottoming out under the load with the trailer connected.
gmcman
Explorer
Apr 01, 2013
randallb wrote:
At the mileage you have mentioned I would buy a new vrhicle instead of throwing money at a possibly hard to locate shake.
Randy

Can't do it..been too good to me....still has a lot of life left, hopefully anyway. I wanted to think the driveshaft was the culprit but why would it shudder when the torque application was at it's lowest? Not exactly the lowest but at the given speed and RPM, no shudder in the lower gears.

The driveshaft was shortened 1.5 inches, U-Joints are of high quality. When I pick the trailer up I will confirm whether or not it was at TC lock but I'm 99% sure it was.

I did speak to someone who is well versed in these tranny's and he believes the TC clutch was the cause. Given the mileage it may just be starting to show it's face and there is a fix for it. Could be the TCC solenoid but more likely adding more fluid to the clutch generally fixes this problem by enlarging the TCC isolator valve bore? I believe that's what it was.

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What would cause a shudder under load

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