Hesitation Accelerating in 2nd Gear. Ideas??

[DavidRam]

I just noticed a hesitation while accelerating through 2nd gear. I watched the rpms and they climb, hesitate, climb, hesitate. And I can feel it too, a subtle hesitation in accelerating.

As the rpms climb, it happens about every 200-300 rpms, almost like clock work.

I only starting noticing it since my gear swap (3.55 open dif to 4.10 lsd) that was done two weeks ago.

In neutral, I revved the engine and watched the rpms and it revved smooth and normal.

FYI, 6,000 miles on the truck, HF tune, 2wd.

I would appreciate any thoughts you guys I have about this.

EDIT: I just checked again and this hesitation happens in all gears.

 

[DavidRam]

EDIT: I just checked again and this hesitation happens in all gears. As the truck accelerates it pauses every couple hundred rpms.

Has anybody experienced this??? I kinda feel like I am talking to myself... Lol!

 

[VolsRam]

It's probably because you're driving a 2x2 truck . Just kidding David. I haven't done a gear swap yet, so I haven't seen this before. Hopefully someone else has and knows what's going on.

 

[DavidRam]

It's probably because you're driving a 2x2 truck . Just kidding David. I haven't done a gear swap yet, so I haven't seen this before. Hopefully someone else has and knows what's going on.

I was driving a 1x1 until I got the lsd installed!

Nobody has words of wisdom on what could be making my truck have the above issue??? Do I have to say pleeeeeeeeease...

 

[TylerB]

Can you hear and/or feel the engine hesitating and coinciding with the tach? Or is it only on the tach that you've noticed?

 

[DavidRam]

Can you hear and/or feel the engine hesitating and coinciding with the tach? Or is it only on the tach that you've noticed?

I can feel it too. First, I noticed the rpms increasing - hesitating - increasing during acceleration. So I paid attention to see if I could feel it at the same time and I could.
With normal driving it's hardly noticable, but the harder I accelerate the more I can feel it.

It's weird. Off the line it begins immediately and every 200-300 rpm is just hesitates for a second and then keeps climbing.

I had 4.10 gears and lsd done 2 weeks ago. I can't see how that would have anything to do with it.

For now, I returned my DS to stock, to rule that out. But don't know what else to check... Any thougts?

 

[TylerB]

I only noticed mine doing at very, very light throttle when trying to slowly accelerate up an incline. I could hear it and feel it, but the tach didn't show it, so I just chalked it up to my looser converter. I'm not sure what ro check, but I remember '11s and some '12s had an issue with the stock converter when they first started showing up.

 

[DavidRam]

The tach shows it very clearly. The needle literally stops for a second and then moves again...
But it doesn't do this at all when I rev in neutral

 

[DavidRam]

To trouble shoot this:
I returned my DS to stock, no difference.
Checked my intake for any air leaks, everything was good.
Checked my exhaust and headers for leaks, nothing.

The truck has this choppy acceleration. It isn't dramatic, but a noticeable hesitation every couple hundred rpms, and the tach climbs - stops for a second - then continues to climb. Grrrrrrrr

I don't know what else to check... please help with some ideas.

 

[HLram]

Maybe something in a bind in your rear diff from the gear swap? How many miles since the swap? Don't you have to break the gears in? Maybe they will smooth out after the break-in period. Drive it for a while and then check the temp on the differential to see if they are hotter than normal. Maybe the driveshaft wasn't timed correctly when they re-installed it. Check that as well. Maybe limited slip is not working properly and now you have a posi-trac lol. Jack the truck up and put it in neutral and turn the rear tires and see if there is a binding.

 

[DavidRam]

Maybe something in a bind in your rear diff from the gear swap? How many miles since the swap? Don't you have to break the gears in? Maybe they will smooth out after the break-in period. Drive it for a while and then check the temp on the differential to see if they are hotter than normal. Maybe the driveshaft wasn't timed correctly when they re-installed it. Check that as well. Maybe limited slip is not working properly and now you have a posi-trac lol. Jack the truck up and put it in neutral and turn the rear tires and see if there is a binding.

Good points. Thanks so much for the info. I am a fish-out-of-water with this stuff...

It's been 300 miles since the gear swap. What would a "binding" be like symptom wise??

Do you think the highest rated differential shop in my area, and a guy who's been doing truck differential work for over 30 years, would make a mistake like timing the drive shaft wrong??

Do you think I should just stop being paranoid, and just drive it until the break-in service and let the shop check eveything??

How do I verify if the lsd is working properly?? Would it have anything to do with the gear oil? I used RP, but did not add the lsd additive, because I was told the RP already has it...

 

[DavidRam]

Is there any chance that, I needed to add the lsd additive???

Any opinions on whether the Royal Purple does the job without it??? If my lsd isn't locking up properly could that have to do with the lsd additive not being present???

 

[TylerB]

The royal purple is fine eithout the additive. I used it for over 10k miles till I had to swap a wheel stud and so I went with cheaper fluid and the additive this time around.

 

[BigWilly]

I know this an oldie but OP did you ever figure this out? I noticed my bone stock 2012 Express is doing something similar.

Thanks
*****

 

[DavidRam]

I know this an oldie but OP did you ever figure this out? I noticed my bone stock 2012 Express is doing something similar.

Thanks
*****

I just chalked it up to a ****** torque converter and forgot about it, lol!

 

[hemihustlin]

Did you change the torque converter?

 

[BigWilly]

Thanks for the responses. Mine seems to only happen between second and third gears. RPMS will climb then dip for a millisecond then climb again. It's barely noticeable. I'll mention it to the dealer and see what they say. Truck is still under warranty.

 

[DavidRam]

Did you change the torque converter?

Nah, it isn't that bad. I haven't even paid attention to it lately...

Thanks for the responses. Mine seems to only happen between second and third gears. RPMS will climb then dip for a millisecond then climb again. It's barely noticeable. I'll mention it to the dealer and see what they say. Truck is still under warranty.

Just for fun, see if it does the same thing in tow/haul mod. That is where mine stops doing it.

 

[BigWilly]

Nah, it isn't that bad. I haven't even paid attention to it lately...



Just for fun, see if it does the same thing in tow/haul mod. That is where mine stops doing it.

Yep tried it yesterday in tow/haul and no issues!

 

[HammerHead]

Do some logging for HF, I be the can get it cleared up.