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HARD SHIFT AT 20 MPH
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=66847		 Page 3 of 3
Author:  thermorex [ Thu Sep 18, 2014 10:38 pm ]
Post subject:  Re: HARD SHIFT AT 20 MPH
lars0247 wrote:
I replaced the ball joint some months ago as it was somewhat loose.

This has made no improvement on the rough shift at 20MPH from 2 to 3 on my CRD.

I think there is a thread somewhere here on lost about hard shifting, if I find it I'll post the link. Pretty much lots of people complained about hard shift at about 20 MpH. The general consensus was that it's a tcm quirk, and it doesn't happen so obvious under harder acceleration. And it's only when upshifting no downshifting. At 10MpH it switches to 2nd. At 35 MpH it switches to 3rd. But there is another shift, at 20 MpH, and I'll be darn if I know what gear is that, 2nd prime? I understood 2nd prime is used only for downshifting from 4th, when 3rd wouldn't be low enough. If anybody knows, I'd appreciate the input, this has been something on my mind for years...
Author:  flash7210 [ Fri Sep 19, 2014 6:11 am ]
Post subject:  Re: HARD SHIFT AT 20 MPH
The shift pattern goes like this

OD-on: 2nd @ 10 mph, 3rd @ 20 mph, 4th @ 35 mph, 4th + lockup @ 51 mph, 5th + lockup @ 60mph

OD-off: 2nd @ 10 mph, 3rd @ 20 mph, 3rd + lockup @ 37 mph.

2nd prime is only a passing gear and I don't know exactly what you have to do to activate it.
Author:  dirtmover [ Fri Sep 19, 2014 7:52 am ]
Post subject:  Re: HARD SHIFT AT 20 MPH
flash7210 wrote:
2nd prime is only a passing gear and I don't know exactly what you have to do to activate it.


It uses a different 2nd gear ratio depending on whether it is shifting up or down hence the 2nd prime.
Author:  thermorex [ Fri Sep 19, 2014 9:55 am ]
Post subject:  Re: HARD SHIFT AT 20 MPH
flash7210 wrote:
The shift pattern goes like this

OD-on: 2nd @ 10 mph, 3rd @ 20 mph, 4th @ 35 mph, 4th + lockup @ 51 mph, 5th + lockup @ 60mph

OD-off: 2nd @ 10 mph, 3rd @ 20 mph, 3rd + lockup @ 37 mph.

2nd prime is only a passing gear and I don't know exactly what you have to do to activate it.

Got it, thanks flash, that makes sense. 2nd prime, as I remember, is for when you pass something in 4th, and you step harder on the acceleration, 3 would be too "long", 2nd would be too short, so they added 2nd prime. I heard people were changing tcms on hemis to get the 2nd prime working as 3rd, 3rd as 4th, 4th as 5th, so on. In theory, 545 rfe has 6 forward speeds anyways.
Author:  ebbnflow [ Fri Sep 19, 2014 2:40 pm ]
Post subject:  Re: HARD SHIFT AT 20 MPH
lars0247 wrote:
I replaced the ball joint some months ago as it was somewhat loose.

This has made no improvement on the rough shift at 20MPH from 2 to 3 on my CRD.


I don't think he is talking about ball joints, but something similar above the center of the differential. I have yet to look under my jeep as it is the wife's DD.

A part number would be nice OP.
Author:  papaindigo [ Fri Sep 19, 2014 3:30 pm ]
Post subject:  Re: HARD SHIFT AT 20 MPH
What mtrapuzz is referring to is the rear upper control arm PN 52088901AD. I find it a bit odd that an issue with this part would cause an automatic transmission shift issue but it could cause drive line binding so maybe a shift issue is possible. If not then I would not be surprised if one experienced a "clank" in the drive line during shifts.
Author:  ebbnflow [ Fri Sep 19, 2014 10:43 pm ]
Post subject:  Re: HARD SHIFT AT 20 MPH
Thanks Papa. Based on OPs description, I think you're right. That is not what I thought it was. I don't see how upper control arms can cause a hard shift only at 20 and not other gears?
Author:  lars0247 [ Fri Sep 19, 2014 11:17 pm ]
Post subject:  Re: HARD SHIFT AT 20 MPH
Deleted
Author:  lars0247 [ Fri Sep 19, 2014 11:28 pm ]
Post subject:  Re: HARD SHIFT AT 20 MPH
ebbnflow wrote:
lars0247 wrote:
I replaced the ball joint some months ago as it was somewhat loose.

This has made no improvement on the rough shift at 20MPH from 2 to 3 on my CRD.


I don't think he is talking about ball joints, but something similar above the center of the differential. I have yet to look under my jeep as it is the wife's DD.

A part number would be nice OP.


I am referring to the large single ball joint that is pressed into the rear upper control arm and connects to the top of the rear differential. This can wear, giving a somewhat drifting feeling when driving, particularly on the freeway. Replacing it made mine handle better, but there was absolutely no effect on the 2 3 harsh shift.

Upon further research, I might suggest googling the following

harsh 545rfe "trannybuilder.com"

And then reading the results using the Google cache feature as trannybuilder.com site is a paid membership forum ($325 minimum per year) for Transmission repair shops to share their problems and fixes. Apparently, these 545RFE units also have issues on other vehicle platforms. One guy said he fixed similar problem by cleaning / polishing one of the bores in the valve body. I think there is alot of good information there.
Author:  ebbnflow [ Fri Sep 19, 2014 11:29 pm ]
Post subject:  Re: HARD SHIFT AT 20 MPH
Truckbouy2 had both his TCM and valve body replaced under warranty and the problem still returned.
Author:  lars0247 [ Fri Sep 19, 2014 11:34 pm ]
Post subject:  Re: HARD SHIFT AT 20 MPH
ebbnflow wrote:
Truckbouy2 had both his TCM and valve body replaced under warranty and the problem still returned.


True, but there is tons of info on that site, but you can only read it with a membership or by using the Google cache feature.

I wonder if they replaced the Solenoid assembly on Truckbouy2's CRD as I know this can be had separately from Chrysler.

A bad solenoid might cause this issue.
Author:  ebbnflow [ Sat Sep 20, 2014 11:15 am ]
Post subject:  Re: HARD SHIFT AT 20 MPH
I replaced the solenoid pack in my valve body and it did not help at all.

Thanks for sharing the link to trannybuilder.
Author:  lars0247 [ Wed Sep 24, 2014 7:09 pm ]
Post subject:  Re: HARD SHIFT AT 20 MPH
Well, I think I might just quit trying to solve that which Chrysler themselves admits is a software problem, apparently without any fix...

------
This message below was sent to Transengineer, a regular on Dodge and Cummins forums who by the what he talks about, appears to be an engineer from Chrysler.


To revisit this topic, I still have the problem. I have since bought a scan tool that allows me to learn the transmission. It will shift good at first after the quick learn with the OD CVI starting at about 50, but then no matter what I do, the OD CVI starts to creep upward over maybe 200 miles of city driving, and finally stabilizes at about 70 at which point there is a very noticeable bind during the 2 to 3 upshift (like hitting the brake hard momentarily).

The odd thing is that this summer, when temperatures never were much below 75F during the day, the problem never occurred. In fact, I went for two months without the issue, but once colder mornings came (50F), the problem is back again.

Curiously, during the warmer weather, I pulled a heavy trailer, and after I unhooked it, the 2 3 shift was harsh, but I simply drove around the block a few times, and shifted between 2 and 3, and it smoothed right out.

Also, when the air is colder, no amount of drive learning helps, even though the oil temp is above 110F.

It is my understanding that the TCM "optimizes" the time it takes for shifts to occur by adjusting the CVIs. What I don't understand is why it would adjust them to the point of having a bind.

Anything that you would recommend checking before I pull the transmission and replace it with a remanufactured unit?

Thank you.
---End Quote---
Lars,

All I can recommend is doing a quicklearn whenever the OD CVI gets too high. The problem is in the learning routine in the software. I doubt you have a transmission hardware problem. I don't think replacing the transmission will fix anything. I think the problem is in the software, and unfortunately the only workaround is to re-learn it when the CVI gets too high.

At least re-learning it is easier (and cheaper) than replacing the transmission.
Author:  thermorex [ Thu Sep 25, 2014 8:46 am ]
Post subject:  Re: HARD SHIFT AT 20 MPH
Thanks for sharing, I thought this is the issue but now with this confirmation I am sure about it.
Author:  racertracer [ Sun Mar 06, 2016 11:33 pm ]
Post subject:  Re: HARD SHIFT AT 20 MPH
Sticky gum and varnish deposits in the valve body cause erratic shifting.

According the transmission rebuild shops, the valve body needs cleaning and sometimes even rebuilding.

Old fluid and gummed up sticky moving parts in the valve body is the cause for hard and irregular shifts.

Fluid replacement will clean it up but if it doesn't solve the problem then run a transmission solvent thru it for a few hundred miles before replacing the fluid.

The solvent will break down the varnish.

If your ATF has never been changed, then you need to start there.

1. Seafoam Transmission solvent.

2. Amsoil transmission flush.

Follow directions on the can and change the transmission filters too.
Author:  mecne [ Thu May 19, 2016 11:05 am ]
Post subject:  Re: HARD SHIFT AT 20 MPH
racertracer wrote:
Sticky gum and varnish deposits in the valve body cause erratic shifting.

According the transmission rebuild shops, the valve body needs cleaning and sometimes even rebuilding.

Old fluid and gummed up sticky moving parts in the valve body is the cause for hard and irregular shifts.

Fluid replacement will clean it up but if it doesn't solve the problem then run a transmission solvent thru it for a few hundred miles before replacing the fluid.

The solvent will break down the varnish.

If your ATF has never been changed, then you need to start there.

1. Seafoam Transmission solvent.

2. Amsoil transmission flush.

Follow directions on the can and change the transmission filters too.


Has anyone tried this?
So far I have , changed fluid and filters , installed the Transgo shiftkit and another TCM from a Part out.
When I first put the other TCM in it was great .. the way it should be for a couple days , then it learned the bad shift again.

I've tried swap put the TCM's a few times , and both are in the same state now. I could go swap the one on the bench in and it will hard shift 2-3 .
I've done many quick learns and slow learns , it always seems to go back.

I drive accordingly now , I give it more throttle when it's about to shift . high RPM = smother shift. Would be nice to have a smooth shift between 2-3

M
Author:  ebbnflow [ Thu May 19, 2016 3:48 pm ]
Post subject:  Re: HARD SHIFT AT 20 MPH
I battled this issue for about 15k miles and tried everything short of pulling tranny to fix it. Got fed up and bought a low mileage 545rfe from a wrecking yard out of a Dodge Ram 1500 5.7l. Replaced both the tranny and TC. Problem is gone. Tranny shifts like butter.
Author:  mecne [ Fri May 20, 2016 8:36 am ]
Post subject:  Re: HARD SHIFT AT 20 MPH
ebbnflow wrote:
I battled this issue for about 15k miles and tried everything short of pulling tranny to fix it. Got fed up and bought a low mileage 545rfe from a wrecking yard out of a Dodge Ram 1500 5.7l. Replaced both the tranny and TC. Problem is gone. Tranny shifts like butter.


Thanks for the reply ebbnflow ,
I have been looking at doing the torque converter , pump and coil pack as I have a bit of shudder when into the throttle.
I would consider this as it would be basically do the same thing ..

What Year RAM 1500?
Did everything bolt right up?
Did you change the TCM or is it stock Jeep?

Cheers,
M
Author:  ebbnflow [ Fri May 20, 2016 12:26 pm ]
Post subject:  Re: HARD SHIFT AT 20 MPH
I got it from a 2011, but would not go newer than 2009-2010 after learning a few things.

See:

viewtopic.php?t=78883
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