Hi all, just purchased an '88 B-150 ram van, 5.2, auto. w/ 76,000 on it, I'm getting vibration after about 10 minutes of driving @ 45 - 55 mph, at first I thought it was a bad tire but after all new tires it's still there even when slipping into nuetral while rolling, now I'm suspecting transmission even though it shifts great and the oil doesn't smell burnt, could it be universal joints ?? any advice appreciated, thanks, Tim

 

Since it does not do it for the first 10 minutes at 45 to 55, I think that rules out the U joints. They are easy enough to check though, any slop is too much.

When slipped into neutral while driving and it continues, are you keeping the rpm's up?

Just wondering if the engine is misfiring on a cylinder or 2 at that speed and rpm.

Since it only happens after something warms up, it is/was likely either the tires, or the tranny, or a bent, out of true rim. Does it appear like they used a lot of balancing weights on any one tire on your new tires?

Do a search for "key dance" which will tell you how to obtain codes, and see of you get one for the lock up torque converter. See if hitting the OD off button does anything. If you have no OD off button, you do not have a lock up torque converter and then disregard.

45 to 55 under light accelleration is when I experienced ('89 b250 with an A500 tranny)Torque Converter Clutch chatter but only under light accelleration. Letting off the gas or forcing a downshift eliminated it. It was caused by the improper Tranny Fluid, and cured by a flush with the correct.( ATF +3 or ATF +4)

 

Thanks for reply, the engine runs very smooth and quiet at all speeds, I have the drivshaft off, no play in joints but a little rough so i will replace them, actually there is no button for a lock up but according to the Equipment I D tag it does have a code DHA lock up torque converter and I noticed while driving it does shift again after 3rd gear, so question is is it normal to have a lockup without a button ?? will post results of new U joints and check for bent wheel , Tim

 

Thank you for not spelling "quiet" quite, a pet peeve of mine.

I do not know which tranny you have. I would think every OD equipped vehicle has an "OD OFF" button. In my '89 Factory service manual it says that only 2 automatic transmissions were available. The 3 speed and the 4 speed OD as optional. Don't know about an '88. Don't know if the 3 speed has a lock up torque converter.

You cannot rule out the engine. It can be misfiring just at that speed as a certain amount of air pressure under the doghouse might push worn SP wires into ground.

The thing which should make diagnosing easier is that it only does it after it warms up. A bent rim will do it warm or cold. A new tire with a separated belt could warm up and vibrate. The engine could misfire after warming up, or something internal to the tranny could be acting up when it gets up to temp.

Did you check for engine codes stored in the ECM?

Go underneath ans follow the wires to the Tranny. Remove and clean the connections. I think if you do not have overdrive or lockup, there will only be one set of three wires leading to the neutral safety switch. If you have 2 sets of wires then the other set is to trigger the lock up solenoid and or the overdrive.

When my A500 was shuddering at 47 to 60 mph under light accelleration due to torque converter clutch chatter, it would only do it when warmed up. The whole time it still shifted fine. The fluid looked and smelt fine. The problem was it was dexron, and chrysler trannies are very tempermental about their fluid.

Chrysler developed ATF +4 out of necessity, and it is one of the best ATF's available.

If at anypoint the previous owner did a flush or pan drop, it is very likely they used the incorrect fluid. But since you say it shudders/ vibrates when taken out of gear it makes TCCC much less likely, if not impossible.

http://www.allpar.com/mopar/transmissions/fluids.html

 

1. Is it quite when idling in park?
2. Is it quite when you first take off?
3. Is it quite when moving in reverse?
4. Is it quite when your cruising along in top gear?
5. Is it quite when slowing to a stop?
6. Is it quite when the vibration is not present?
7. Is it quite when the vibration is present?
8. Is it quite when sitting still in drive?
9. Is it quite when taking turns?

 

Check the rear tranny mount at the crossover support. I think you're going to find that it's in rough shape.

 

You bat rastard!!

 

I had to laugh when you posted the quite/quiet pet peeve, because I have a similar issue. When someone mentions a problem with their breaks instead of brakes, I have to bite my lip until it hurts just so I don't go off the handle over it.

 

Well, it's better than seeing beaks

 

I see you showed up at that other site I posted the link to.