Transmission skipping or 'fall-out' ?

[dangerous]

My 99 Suburban 1500 has 155k miles on it. At 145k, I had the transmission fluid purged - thought I was doing the right thing.

Anyway - it 'skips' now. To try to explain better - it feels almost like you went over a few bumps in the road. Then it goes away for 10 - 20 secs. At first I thought it may be the OD Converter cycle lock up - but it does it in 3rd and OD. You can feel it at 55 when you level the gas off and are cruising. It does appear at lower speeds...45, etc It also
ocurrs at high speeds, but you really have to 'feel' for it at the higher speeds.

Last - it almost feels like a 'stumble' from the engine, but I think it is indeed the transmisison.

Last last - a few weeks ago - I heard a noise in the transmission - it was heard on a cool (40 degrees) early morning startup and lasted about 4 blocks of driving. I heard it the next day for a short period and then never again. It was like a whining/grining gear noise.

thanks

[dangerous]

GMCMudBogger - where are you? :-)

[rsracer]

Originally Posted by dangerous

My 99 Suburban 1500 has 155k miles on it. At 145k, I had the transmission fluid purged - thought I was doing the right thing.

Anyway - it 'skips' now. To try to explain better - it feels almost like you went over a few bumps in the road. Then it goes away for 10 - 20 secs. At first I thought it may be the OD Converter cycle lock up - but it does it in 3rd and OD. You can feel it at 55 when you level the gas off and are cruising. It does appear at lower speeds...45, etc It also
ocurrs at high speeds, but you really have to 'feel' for it at the higher speeds.

Last - it almost feels like a 'stumble' from the engine, but I think it is indeed the transmisison.

Last last - a few weeks ago - I heard a noise in the transmission - it was heard on a cool (40 degrees) early morning startup and lasted about 4 blocks of driving. I heard it the next day for a short period and then never again. It was like a whining/grining gear noise.

thanks

I have a similar problem with my 2002. It shutters at low speed and when going up hill. I also recently had my tansmission fluid changed. Any ideas?

[sjcrft]

Originally Posted by rsracer

I have a similar problem with my 2002. It shutters at low speed and when going up hill. I also recently had my tansmission fluid changed. Any ideas?

My 97 Does The Same at 50+ Mph ,Tranny Shop Said It was Lockup Torque Conv ,Replace or just deal with??(it feels like bumps in the road)

[dangerous]

Tonight I will be checking the tranny while driving using a computer type monitoring device. A friend has it and will be able to monitor the actions of the transmission and actually seee what is happening while we are driving. I just spoke with him and he feels pretty sure it is the Lock Up switch anyway... ??? will get back

[corning_d3]

I'm thinking it's a lock-up problem, also. Also, your transmission can engage the torque converter clutch in 3rd or 4th..

[randynight]

I had a '94 that done that and the '02 I have now has done that. I was told it likely was the tc lock up thing. Put 2 cans of Lucas in the '94, fixed it. Flushed the trany in the '02, added the additive the quick lube had to go with the flush and a can of Lucas and it stopped the vibrations.
What I was told to do: when it does it keep your foot on the gas and tap the brake pedal enough to light up the brake lights and see if it stops. As soon as you hit the brake it kicks out the tc lockup or stops it from trying to lockup.

[dangerous]

I will try the brake test.....

Results from last nights Test....

From what I understand, the transmission itself is fine. The computer he hooked up said that I have TCC (converter) slippage (which he thought might most likely be the result of a damaged stator. ) The TCC is cycling way too much. He said that possibly the 3-2 shift soleniod could be sticking and could be the result of the backflush I did this summer - knocking a bunch of crap loose and plugging the solenoid.

His guidance is to change the filter (which I will do this weekend) and then a new converter if that does not work. But he wants to do another diagnostic test after the filter change to make sure the 3-2 solenoid is operating the way that it suppose to........if not........then the soleniod should probably be replaced before the converter.

[corning_d3]

Hmm, the stator and the torque converter clutch are 2 seperate components in the converter. A bad stator would reduce low end torque multiplication, but has nothing to do with the TCC. I've also had this problem, but updated PWM and TCC solenoids fixed the problem. A faulty 3-2 shift solenoid would prevent 3-2 downshifts, but shouldn't affect TCC apply. There are a few things that cause converter clutch slippage... Low fluid pressure, worn clutch friction material, and a faulty TCC solenoid . It's fairly easy to get to. After removing the transmission side cover(drivers side), it's located on the lowest left-hand side of the valvebody.

[corning_d3]

Also, I've heard of this problem being fixed by changing the plugs, wires and coil, even if they all test/look fine..

[dangerous]

Thanks d3....... If my memory serves me right, the test indicated that the TCC switch was working as it should. He did say that he did not know why there were no pressure readings - possiibly from that part of the test unit not functioning? I appreciate the input and will get back

[dangerous]

OK - replaced:
A. ATF filter
B. 2 Solenoids (1-2 and 2-3 shift) on rear of valvebody
C. 1 switch (TCC) on front right side of valvebody.

I took it for a drive last night. The traffic preventing me from 'cruising' at a set speed for a long period to really get a good test. I think I still feel the same issue occurring - but I just need to drive it again to confirm.

I did tests on the old switched that I removed and they appeared to be operating fine - well - at least they 'clicked' into and on/off mode when 12v was applied. - Is that any kind of worthwhile test?

We will retest with the ODB mobil computer unit this coming week and I will give status.

[corning_d3]

I've misdiagnosed a dodge ram transmission thinking it wasn't the solenoid, but it turned out even though it tested ok, it was bad. But the scanner will be a sure way to tell. If the transmission still acts up, you may want to think about changing your plugs and wires..

[EA6BMECH]

Could be something as simple as the wrong ATF fluid. The Dodges will act funny if you put regular DexronIII in them if I remember correctly. Dad's Caravan did the same thing. Almost like you were running over something til someone told him to use only Mopar ATF. I hear the new ATF+4 is good for the Fords although Mopar makes the stuff.

[Quickpatch]

Originally Posted by dangerous

OK - replaced:
A. ATF filter
B. 2 Solenoids (1-2 and 2-3 shift) on rear of valvebody
C. 1 switch (TCC) on front right side of valvebody.

I took it for a drive last night. The traffic preventing me from 'cruising' at a set speed for a long period to really get a good test. I think I still feel the same issue occurring - but I just need to drive it again to confirm.

I did tests on the old switched that I removed and they appeared to be operating fine - well - at least they 'clicked' into and on/off mode when 12v was applied. - Is that any kind of worthwhile test?

We will retest with the ODB mobil computer unit this coming week and I will give status.

Hello, I am having this exact problem with a 99 5.7 van. I also had my fluid changed. It started at 105,000 for me. I do not see any more posts after you performed the work above. Did this solve the problem? Which item do you think fixed it. Any help would be greatly appreciated.