2008 Loud bang on downshift approx 70 mph when passing

[Edmaude]

Folks,

We have 58k on the truck and it has previously had the trans out for overdrive clutch replacement at 16k. The dealer also put 2 new u-joints in last week. We are getting an intermittent very loud bang when downshifting to pass on the highway at approx 70 mph. It is very abrupt and I have never experienced this in any truck or car I have ever owned.

The dealer can not find an issue, which sucks....Does anyone have any insight?

Thanks
Ed

 

[toms89]

Folks,

We have 58k on the truck and it has previously had the trans out for overdrive clutch replacement at 16k. The dealer also put 2 new u-joints in last week. We are getting an intermittent very loud bang when downshifting to pass on the highway at approx 70 mph. It is very abrupt and I have never experienced this in any truck or car I have ever owned.

The dealer can not find an issue, which sucks....Does anyone have any insight?

Thanks
Ed

Try turning overdrive off first!

Is it stock or do you have any kind of programmer installed??

 

[RI-Matt]

Folks,

We have 58k on the truck and it has previously had the trans out for overdrive clutch replacement at 16k. The dealer also put 2 new u-joints in last week. We are getting an intermittent very loud bang when downshifting to pass on the highway at approx 70 mph. It is very abrupt and I have never experienced this in any truck or car I have ever owned.

The dealer can not find an issue, which sucks....Does anyone have any insight?

Thanks
Ed

Ed, is it like it's bucking when it happens ? My 06 F150 did this and it felt like I got rear ended, it ended up being a bad coil that wouldn't always ignite the plug and fuel would dump into the cylinder then ignite on the next stroke and BAM almost like a small explosion. By the way it would only do this under load ( like downshifting )
Worth a look into.


Matt

 

[GAINMOB]

sounds like bad luck...f150 and the expy?

 

[Edmaude]

Truck is bone stock with no mods or anything. Would a bad torque converter do this?

 

[eddiemoney]

Truck is bone stock with no mods or anything. Would a bad torque converter do this?

It might, but i would think you would feel it from a stop too

 

[BlimpinDave]

I have an 08 EL and just drove from TX to AZ. While passing under cruise control it would do the same thing, especially going uphil, but wouldnt do it with cruise turned off. It felt like my entire truck was going to shake in half and I would lose the transmission it was so hard.

 

[ptmares]

I have just experienced the same issue.....I think. While doing 75mph, and mashing the gas pedal to pass while going uphill. I felt an abrupt clunk upon downshift in what I believed was the drive train. I could feel it in the seat (felt like a rear end impact). Not sure what the problem is. Leading towards near coils I guess. Those things are not cheap.

 

[07ExpoXLT]

No check engine light? if you do, its a bad coil or spark plugs, its back fire. when your on the Highway does it almost sound like its metal to metal hitting when it bangs?.

 

[ptmares]

It doesn't sound like metal to metal. I can't hear anything when it happens. I sure can feel it.

I hope its not transmission related. If I ease onto the gas pedal to pass, there is no noticeable clunk. Seems to happen when I mash it, and the tranny shifts down one or two gears.

Would a bad u-joint cause this kind of feeling, clunk? Rear axles bad?