Low RPM hesitation

[Sheapdog]

I've been experiencing a hesitation or skip while accelerating in the lower RPM range. I can feel the shimmy when it is lagging. Then once I get past it jumps into a lower gear and higher RPMs without issue. If I get on the throttle from the get go there is no lag. Truck has 133K miles on her. Wondering if a tune-up with new spark plugs and get all my fluids changed would be advised, and possibly take care of the issue?

 

[rzr6-4]

following...

 

[Burla]

Does it do it in tow haul would answer your question. Codes would be helpful. rarely is the answer to catch up on maintenance items.

 

[Sheapdog]

I will have to check the tow/haul option later. It is not throwing any codes, just something I can feel. Like a bump or lag. And almost exclusively while accelerating.

 

[Burla]

So everything is good with the engine and rpm's when different rpm bands in park? And you ran the codes or just saying there was no CEL's? If so, it could be leaky valve body. That is what driving in tow haul can diagnose, sometimes. Low rpm shudder can be a few things, but there are usual suspects especially with rfe.

 

[Burla]

When was the transmission last serviced? Condition of fluid? Is level fluid good on dipstick?

 

[Sheapdog]

There are no codes displaying on the dash, I don't have the tools to diagnose or run codes myself. I will check the tow/haul option, and different RPM's when in park. May be a few days before I can post results.

 

[cyborg21]

I have 2020 limited and been troubleshooting this problem for weeks just had the fuel pump recall done 12/5 and haven't had the problem since

 

[Dean2]

Could be fuel or could be transmission. Two most likely. Fuel system cleaner, and new plugs if you have more than 80000 on existing wouldn't hurt for sure.

 

[Sheapdog]

To update this for anyone else running into a similar issue. I had run the truck in the Tow/Haul mode activated and that did help since it would keep the RPM's at a higher point. I could still manage to get the truck to hesitate and struggle if I accelerated at a very slow pace.

As soon as my son's hockey season was over I was able to get the truck into the shop where I had the transmission fluid/pan/filters all changed out, front and rear differential fluids replaced, and spark plugs replaced. My issue has gone away. I think the biggest issue I was experiencing was the transmission fluid and filters. Truck now runs great.

 

[Dean2]

Thanks for reporting back. So few bother and we all like to see how our remote diagnosing worked out.

 

[Burla]

To update this for anyone else running into a similar issue. I had run the truck in the Tow/Haul mode activated and that did help since it would keep the RPM's at a higher point. I could still manage to get the truck to hesitate and struggle if I accelerated at a very slow pace.

As soon as my son's hockey season was over I was able to get the truck into the shop where I had the transmission fluid/pan/filters all changed out, front and rear differential fluids replaced, and spark plugs replaced. My issue has gone away. I think the biggest issue I was experiencing was the transmission fluid and filters. Truck now runs great.

So if tow haul basically fixed your hesitation, and it sounds as if that was true, it didnt have anything to do with plugs. Now i had new transmission fluid fix low rpm shudder, and it sounds like that is probably what helped you. However if it comes back before 10k miles, the real issue could be a leaky valve body. You could just use a gasket to fix this, but the "correct" way to fix it is a plate and grind valve body if needed, like shaving a warp head only in valve body, it is a lot easiest then it sounds. The only way it isn't this is if there was a bad fluid level or something wrong with filter, which is very possible those OEM canister filters are junk, if they stiffen up it could literally lead to a hesitation. See synthetic filter options for rfe thread ram forum for next time.

 

[Burla]

Learn about valve body here. 3 minute mark tells you about what I was saying gasket or plate.

Product Overview: ATS 68RFE Valve Body and ATS Co-Pilot

Clint Cannon, President of ATS, describes the inherent weaknesses of the 68RFE (545RFE, too) valve body. This is a comprehensive overview of the numerous pro...

youtu.be

 

[Sheapdog]

Looking at my notes of what my mechanic said, "transmission lines have a small leak, and should be replaced eventually. Keep an eye on your fuid levels. Drive Axle needs fixing and is considered a higher priority over the lines." I do recall him saying something about the lines previously. I don't see any fluids indicating any leaks, but then again I have a gravel driveway and nothing where I park at work.

Thanks for all the info guys. I will look into your suggestions to try and educate myself a bit more.

Love this forum.

 

[Burla]

Always check fluid level with any transmission issue, of course you only found out this was involving the transmission overtime, so you didn't understand this was a trans issue first so gentle sin not checking the level. I live on gravel as well, you would know if there was any leaks. Of course leaky valve body is something very different, it doesn't leak anywhere visible, it just pushes fluid away from the spots it is needed, it stays inside the transmission. But at least for a while, check the transmission level maybe every fill up, leave car running and car in neutral, yes with parking break on. Neutral spins the fluid, park does not spin it, to get an accurate warm level reading I think you need it in neutral. Especially after some shop services a transmission, you really need to check the fluid a couple times when warm.

If these symptoms come back anytime soon my guess is you need to rebuild VB or get a new ASAP.