Transmission (Overdrive?) Problem

JM85 · **Joined:** Thu Jan 05, 2017 11:05 am **Posts:** 5

Firstly, this is my first post, sorry to be asking for help as a first post, I'm normally a lurker and troubleshoot by reading, but I've been through 50 pages of threads and found nothing to help!

Ok, I have a 2.8CRD Jeep Cherokee (2003) here in the UK, my first 4x4, and first automatic that I've owned.

The engine starts fine, first time every time, and drives, but the problem is - the gearbox will change from 1st to 2nd, 2nd to 3rd, and I believe there is also a TC lock just after the change to 3rd, around 30mph (I assume this is what it is, slight drop in revs).

This is where the problems start - those gearchanges from 1st to 2nd, 2nd to 3rd and the tc lock(?) are all smooth, as are downshifts, but the trans never shifts up beyond the 3rd gear.

This means that driving much quicker than 40mph has the RPM a lot higher than I would like, and driving at motorway speeds is just impossible, any long journeys I have to sit in the slow lane at around 50mph to keep the RPM below 2500!

What I've tried so far;

Checked fluid level, topped up slightly above the hot fill mark using ATF+4 - fluid looks clean, no burning smell
Disconnected the battery for 20 minutes to see if it clears any limp mode type codes
Checked codes using the key trick, there are a couple (which didn't clear using the battery disconnect, but I don't believe they are still present as one code relates to cruise control, which works fine) - there is no p0700 code to suggest that there are any transmission codes stored.

I've also tried pressing the overdrive button when I'm at around 60mph to disable o/d - there's no change in rpm whatsoever which confirms overdrive isn't engaging.

I don't want to get rid of the Jeep as it's nice to drive, comfortable and something I've wanted for a while, but I can't afford to spend too much on it, so I'd like to avoid throwing money at it guessing, I'd love to have any ideas of what this could be, and things I should try that are free/cheap!

WWDiesel · **Posted:** Thu Feb 16, 2017 1:05 pm

Check all fuses and make sure none are blown! OD switch may be bad keeping OD locked out at all times? Check the wiring for the OD switch and make sure it has not gotten grounded somewhere as it is a simple ground circuit back to the transmission control module.
Could also be a bad solenoid inside the transmission, Overdrive Solenoid Control.
There are some other sensors and solenoids that play into the operation of the OD via the TCM as well.
You may end up having to get a good transmission shop to fully diagnose the issue.....

JM85 · **Joined:** Thu Jan 05, 2017 11:05 am **Posts:** 5

Thanks for the reply, I should add I had a quick look at fuses/relays to see if I could find any related, I swapped round 2 relays (one for the eATX and one for the Light bar I believe) both were same relays, didn't make a difference.

When I press the o/d button it does light up on the dash, unsure if this would come on if it was a bad ground?

I'm not entirely sure what gearbox I have, so should I have a 4th gear and then overdrive, or is overdrive the 4th gear?

What I feel/observe just now is: Pull away normal, 1st "change" at around 10 - 15mph, another change somewhere around 20 - 25mph (I think, I'd have to drive and double check) and then shortly after that 2nd change, a third which I think is TC lockup?

I've contacted a local auto transmission specialists to see what they think, waiting to hear back from them, but I'm guessing that because I have no p0700 there won't be any codes stored in the TCM/gearbox for them to simply scan, so it would be a more invasive diagnostics (strip down or similar)?

WWDiesel · **Posted:** Thu Feb 16, 2017 3:33 pm

See this for a complete understanding of how the 545RFE transmission functions:> http://www.colorado4wheel.com/manuals/J ... Diesel.pdf
:SOMBRERO:

WolverineFW · **Posted:** Fri Feb 17, 2017 1:00 am

4th and 5th gear are both overdrive gears on this transmission.

Sent from my SM-N910W8 using Tapatalk

JM85 · **Joined:** Thu Jan 05, 2017 11:05 am **Posts:** 5

Thanks to you both - I'll keep the thread updated as and when I find anything out, if anyone else has any suggestions I'm all ears! I'm doing some "light reading" of the troubleshooting pdf!

Bushman5 · **Joined:** Sat Jul 11, 2015 11:05 am **Posts:** 276

When you say lock out the TC , you mean turning the OD off ? ie : the light on the dash OD OFF lights up?

JM85 · **Joined:** Thu Jan 05, 2017 11:05 am **Posts:** 5

Bushman5 wrote:

When you say lock out the TC , you mean turning the OD off ? ie : the light on the dash OD OFF lights up?

I can turn off O/D using the button (the light on the dash comes on) whether the light is on or off the gearbox acts exactly the same - changes from 1st to 2nd, 2nd to third and then no further changes.

What I feel is;

pull away in 1st, pick up a little speed, it changes up into 2nd and revs drop a little due to the gearchange.

carry on in 2nd, build up some more speed, changes into third and revs drop a little due to gearchange

shortly after it changes into third, the revs drop a little bit more, which I thought was something like the torque converter locking up, but I may be talking rubbish I don't know a lot about these.

Once that happens, I can carry on building up speed but it never attempts to change up gears again, so can be at 60mph, almost 3krpm - if I accelerate more I can cause it to kick down into 2nd (obviously not at 60mph!)

WWDiesel · **Posted:** Mon Feb 27, 2017 12:14 pm

There are some speed sensors on the transmission that play into the operation of the transmission by the TCM. You may need to take it to a good transmission repair shop and let them diagnose your problem. They should have the necessary electronic equipment to check for the correct operation of all speed sensor inputs and solenoid operations on the valve body that control gear changes... :roll:

Good luck and keep us posted!

JM85 · **Joined:** Thu Jan 05, 2017 11:05 am **Posts:** 5

WWDiesel wrote:

There are some speed sensors on the transmission that play into the operation of the transmission by the TCM. You may need to take it to a good transmission repair shop and let them diagnose your problem. They should have the necessary electronic equipment to check for the correct operation of all speed sensor inputs and solenoid operations on the valve body that control gear changes... :roll:

Good luck and keep us posted!

Took the half hour drive over to a recommended transmission specialist this afternoon, I'd spoken to him on the phone and he offered to run a diagnostics free of charge and let me know what the problem was/what it would cost to fix.

Really helpful man, I turned up late due to traffic and getting lost, just as he was closing up for the day, but he told me to wait in reception and he'd scan it, he came in with a list of codes (see below) and said he wasn't sure which was causing the issue, but he'd cleared them - he said to drive it home, see how it is, if it continues, bring it back tomorrow and he'd re-scan and see which codes had returned and go from there.

The good news is, so far - driving home, onto the motorway and it now changes from third, into 4th and 5th (overdrive), managed to slow down/speed up a few times to see if it continued working, which it did - I was only able to get up to about 65mph due to traffic, and haven't taken it out again since switching the engine off, but fingers crossed all is well at the moment.

codes were;

p1684 - Battery disconnected
P0871 - Od Pressure Switch Check Failure
P1790 - Fault immediately after shift
P0846 - 2C Pressure Switch check failure
P2704 - Inadequate Element Volume 4C

I thought that limp mode on these gearboxes didn't change gears at all, but now it seems like it was in some form of limp mode possibly due to a bad connection or similar at one point?

WWDiesel · **Posted:** Mon Feb 27, 2017 9:03 pm

JM85 wrote:

WWDiesel wrote:

There are some speed sensors on the transmission that play into the operation of the transmission by the TCM. You may need to take it to a good transmission repair shop and let them diagnose your problem. They should have the necessary electronic equipment to check for the correct operation of all speed sensor inputs and solenoid operations on the valve body that control gear changes... :roll:

Good luck and keep us posted!

Took the half hour drive over to a recommended transmission specialist this afternoon, I'd spoken to him on the phone and he offered to run a diagnostics free of charge and let me know what the problem was/what it would cost to fix.

Really helpful man, I turned up late due to traffic and getting lost, just as he was closing up for the day, but he told me to wait in reception and he'd scan it, he came in with a list of codes (see below) and said he wasn't sure which was causing the issue, but he'd cleared them - he said to drive it home, see how it is, if it continues, bring it back tomorrow and he'd re-scan and see which codes had returned and go from there.

The good news is, so far - driving home, onto the motorway and it now changes from third, into 4th and 5th (overdrive), managed to slow down/speed up a few times to see if it continued working, which it did - I was only able to get up to about 65mph due to traffic, and haven't taken it out again since switching the engine off, but fingers crossed all is well at the moment.

codes were;

p1684 - Battery disconnected
P0871 - Od Pressure Switch Check Failure
P1790 - Fault immediately after shift
P0846 - 2C Pressure Switch check failure
P2704 - Inadequate Element Volume 4C

I thought that limp mode on these gearboxes didn't change gears at all, but now it seems like it was in some form of limp mode possibly due to a bad connection or similar at one point?

Well I am glad you followed the advice presented here and it seems to have worked out in your favor! :wink:

Hopefully your issue will not return, but if it does, let the transmission expert diagnose the problem and go from there...

Best of luck!

GordnadoCRD · **Posted:** Tue Feb 28, 2017 1:51 am

You likely solved the problem yourself when you topped your trans up. Many Auto Transmissions have conniption fits when topped up. This is not one of those. These Transmissions run best and happiest when a bit over-full, so don't worry if you've gone a pint or so over.

Kind of like us, eh? "gimme another pint and call 'er good" :5SHOTS:

racertracer · **Posted:** Tue Feb 28, 2017 3:00 am

To me, it sounds like you need a transmission filter and fluid change. I did this and it solved the hard shifting problems I was having.

Our CRD's are reaching the high mileage mark and most of us don't service the transmission properly or until it's too late. Hence the reason why so many are experiencing hard shifts and other transmission problems. The transmission will not run forever without new fluid and filters and it's an easy job to do just a little messy.

Drop the transmission pan a little and allow the fluid to drain as much as possible. Then remove the pan totally and wash out all of the metal shavings at the bottom and from the magnet. Those shavings are thrown about the transmission and will wear out the plates, clutches and other moving parts if allowed to remain inside a transmission.

Install new filters, then re-seal around the edges of the pan and reinstall it, refill the transmission with 7 quarts of transmission fluid (ATF+4) and your good to go for another 45,000 miles or more.

Drive it normally for several hundred miles and you should notice smoother shifting.

If your transmission still shifts hard after this service, then add a bottle of quality transmission additive (Lucas transmission fix, Auto RX or similar, etc.). If the problem still exists, then a transmission rebuild or replace is in your future.

Transmission (Overdrive?) Problem

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