To F37 or not to F37? That is the question...

T^2 · **Posted:** Tue May 12, 2009 10:06 pm

My CRD is a 2005 Limited with approximately 84000 miles on it. It has never had the F37 CSN done on it. It's still running with the original TC. The problem - I got a sneaky suspicion that the TC is about to go belly up. I can't tell for sure, I don't have a lot of experience with TC's failing (I don't usually buy MOPAR) so correctly recognizing the symptoms requires some measure of a SWAG. The symptoms are hard to describe. It's almost like a stutter (similar to having air in the fuel line but not quite) that only occurs in overdrive (4th and 5th). It feels like very brief momentary losses of power applied to the tranny. It's kind feels and sounds like going over minor bumps in the road - even though I'm on completely new roads. Anyway....

I'm considering selling the Liberty and moving on. I'm at the decision point where you decide if you're going to keep a vehicle for the long haul or sell it while it still has some decent resale value. I need a new truck, so I'm inclined to let the CRD go.

I'm concerned that it might be difficult to sell the CRD in its current state. The symptoms are noticeable - to me anyway. I guess my first step is to get the CRD diagnosed. If it indeed has a TC/Transmission issue then first let me just say "crud!" So, if this is the case then I see two options. Try to get the dealer to perform the F37 or do something like the Suncoast TC and Transgo shift kit. I'd hate to F37 the CRD, but I'll be selling it. That being the case, I don't really feel like dumping more money into it if I don't have to.

What's the going rate for an Suncoast TC etc. install? I presume a new pump would be required? Is Suncoast the go to place or have better/other options been found (I don't frequent this forum like I used to and I lost track of all these detail many moons ago)?

So what would you do?

geordi · **Posted:** Tue May 12, 2009 10:30 pm

I would tell you that if you aren't going to keep the CRD, DO NOT GET THE F37 DONE!!!!!!!!

If you want the F37, as far as the electronic changes, I would be happy to buy your TCM and ECM, AND provide you with matching replacements that have already been "upgraded" so that you could take the truck to a dealer and have them do the TC replacement.

I have a complete set of both computers from an 05 (what I have as well) and would be happy to discuss this with you in a private message. Part of why I want to do this is to get the unmolested code copied so it can be available to the community as a flash upgrade from InMotion. The other part is that I tow probably the most weight of any CRD owner, and I know that the F37 isn't helping my transmission's performance.

Just do NOT let those bloodsuckers at Mopar neuter that CRD.

BTW: The Suncoast conversion is the best option I have heard about, and it should be in the vicinity of $1400 or so if you don't do the install yourself.

ATXKJ · **Posted:** Wed May 13, 2009 12:11 am

You can trade TCM's with me - then take your Jeep in for the F37 - they'll give you a new torque converter and reflash the TCM to F37 specs.

ATXKJ · **Posted:** Wed May 13, 2009 12:43 am

Well - just in case you don't want to trade - still don't let the dealer touch the TCM -
check Car-part dot com and find a local automotive recycling center (junkyard) with a CRD
get the TCM (one of the AZ guys has a spare and said they swap no problem)
take your Jeep to the dealer with the new TCM - let them do the F37 and give you a new TC
drive home - swap back, enjoy your Jeep.

The new TC will probably last at least 50-60K miles and you can save up for the Suncoast

if you do ever decide to sell the Jeep - swap in the F37 TCM

sell the Non F37 TCM to me (I'm serious this time)

RJM · **Posted:** Wed May 13, 2009 6:59 am

My 06 has a build date of 10/05 and has never been flashed, does anyone know if it is F37 or non F37?

Glend · **Posted:** Wed May 13, 2009 7:16 am

I had a vehicle that exhibited the same problem as yours (that studder over a bump) that gradually turned into jumping out of gear (whirring, etc), after stripping it all down it turned out to have a TC that was like new but the solenoids were going. I'd let a GOOD tranmission specialist have a look at it for an assessment. Don't forget that the Service Manual has diagnostics that can be performed as well.

CRDMiller · **Posted:** Wed May 13, 2009 4:03 pm

f37 is easy to test for. Do you shift into top gear at 65 mph? (assuming your speedo and whatnot is adjusted) is your crd runnig at 2k+ rpm between 40 and 55 mph? That's f 37.

Edit. I would love to buy your non f37 tcm :P a lot of us would.

RJM · **Posted:** Wed May 13, 2009 5:35 pm

Yup & yup, crap & crap! however on the brighter side, I have access to an 05 Sport wreck, short of swapping things out to my unit, is there any other way to tell??

ATXKJ · **Posted:** Wed May 13, 2009 11:30 pm

type the last 8 digits of the vin into the Jeep site and it'll tell you if there are any recalls outstanding
http://www.jeep.com/en/owners/

if F37 is there - it hasn't been updated

MTB_TDI · **Posted:** Thu May 14, 2009 12:07 am

I've got a F37 tcm in my toolbox that you could borrow for a while. You can tell if yours is f37d by checking the shift points. If she locks out in 5th at 65 shes F'd if she shifts earlier then she's a virgin and keep her that way. Also, if you have access to an obd II scanner, you can get the info off of the tcm. if she ends in AF you don't have the F37. I have and AF and an AJ tcm. Guess which one I use!

05infernoCRDL · **Posted:** Thu May 14, 2009 1:59 am

hold up a second here..... i think my 5th gear shift is at 60 ish... i know it is below 65... so i might have an unF37'd tcm?

Joe Romas · **Posted:** Thu May 14, 2009 8:19 am

05infernoCRDL wrote:

hold up a second here..... i think my 5th gear shift is at 60 ish... i know it is below 65... so i might have an unF37'd tcm?

Yeah, F37 will not do it's final shift till at least 62 mph but will then hold it till around 58 mph. The original shift point, mine had it for the first two weeks of ownership, was in the mid to late 50's :lol:

And as I remember F37 is a "TBS" (customer satisfacation) and not a recall so I don't think they're going to do it for free on a 84,000 vehicle.

If it were me I would take it a independent shop and have a suncoast or the newer Chrysler TC put in if it is a TC.

And as Geordi said
Just do NOT let those bloodsuckers at Mopar neuter that CRD.

nursecosmo · **Posted:** Thu May 14, 2009 12:09 pm

That's weird. My rig which has been neutered, shifts into 4th at exactly 50MPH which is exactly 2000 RPM, and into 5th at exactly 60MPH which is exactly 2000 RPM.

If I drop back from 50 to 48 MPH, it will still hold 4th, and I can drop from 60 to 56MPH and it will still hold 5th. I usually run the 55MPH roads in my area in this way for better fuel economy.

CRDMiller · **Posted:** Thu May 14, 2009 2:53 pm

Speedo incorrect, or different size shoes. (or both)

When i got the 32's befor i had the computer programed ( it was already 5 mph low), i was shifting into top gear at 70 mph (actual not indicated)

YOU can get your computer programed in suc a way that you shift into top gear at a much lower rpm but your speedo will be 30 mph off :P

I've thought about it.

But i rather have a accurate 20-50 mph speedo (mine is properly set up and is 100% accurate from 0-50 or so, then it's way off, for instance 55 is 56, 70 is 79)

And the grade hunting logic would be useless.

And your tc would explode.

And you could get bad economy on hilly terrain.

I'm just saying i'm getting good mpg the way it is, but i often turn off od to get lockup at 40 (read almost always) so why mess with it? :P

EDIT: In reguards to the jeep owners website, i think it's useless. I checked my vin before i bought it and it came up clean.

I took it in for a unrelated repair that ended up being a noisy motor mount, (warranty work) and they f32'd me AND did the ball joints.

danoid · **Posted:** Thu May 14, 2009 3:03 pm

Just because you had the F37 done doesn't always mean the TCM has been reflashed. My TCM wasn't touched by the dealer. (although they charged Chrysler for the work performed anyways - that's 5-star honesty...)

Joe Romas · **Posted:** Thu May 14, 2009 3:10 pm

nursecosmo wrote:

That's weird. My rig which has been neutered, shifts into 4th at exactly 50MPH which is exactly 2000 RPM, and into 5th at exactly 60MPH which is exactly 2000 RPM.

If I drop back from 50 to 48 MPH, it will still hold 4th, and I can drop from 60 to 56MPH and it will still hold 5th. I usually run the 55MPH roads in my area in this way for better fuel economy.

How about 5th and TC lock up? That's what happens with stock tires and F37'ed at 62 mph. Of course it takes a light peddle to make it happen. On mine at just under 70 by the speedo that we know is wrong, I'm turning just under 2000 :wink:

As a side note those produced after 11/25/05 have a newer TC and only got a firmware flash with F37 :cry:

A Royal Flash :roll:

nursecosmo · **Posted:** Thu May 14, 2009 4:28 pm

CRDMiller wrote:

Speedo incorrect, or different size shoes. (or both) .

My speedometer is correct within 1% as verified with GPS. However, even if the speedo is incorrect or the tire sizes change, the indicated shift points should remain constant on all vehicles with the same flash. The shifting is performed based on what the computer is seeing from the various sensors (CPS, Tail shaft speed sensor, TPS, etc) The tachometer and speedometer on the dash can only report what the ECM tells them is happening, so they should all indicate the same speed and tach shift points regardless of actual speed.

nursecosmo · **Posted:** Thu May 14, 2009 4:29 pm

Joe Romas wrote:

nursecosmo wrote:

That's weird. My rig which has been neutered, shifts into 4th at exactly 50MPH which is exactly 2000 RPM, and into 5th at exactly 60MPH which is exactly 2000 RPM.

If I drop back from 50 to 48 MPH, it will still hold 4th, and I can drop from 60 to 56MPH and it will still hold 5th. I usually run the 55MPH roads in my area in this way for better fuel economy.

How about 5th and TC lock up? That's what happens with stock tires and F37'ed at 62 mph. Of course it takes a light peddle to make it happen. On mine at just under 70 by the speedo that we know is wrong, I'm turning just under 2000 :wink:

As a side note those produced after 11/25/05 have a newer TC and only got a firmware flash with F37 :cry:

A Royal Flash :roll:

I don't understand your question about 5th and lockup.

Joe Romas · **Posted:** Fri May 15, 2009 7:51 am

nursecosmo wrote:

Joe Romas wrote:

nursecosmo wrote:

into 5th at exactly 60MPH which is exactly 2000 RPM.

How about 5th and TC lock up?

I don't understand your question about 5th and lockup.

When does the Torque Converter clutch lockup? Your RPM's at 60 indicate your TC is not locked up or your not in fifth :lol:

My speedo says a tad under 70mph at 2000 rpm's. So it would seem your not in 5th or the TC clutch is not locked up :wink:

For most F37'ed the speed for that is 62-64 mph. Also keep in mind the TCM does not lock the TC clutch untill the transmission fluid reaches normal operating temperature. Another variable here is there are more then two versions of TCM programming. I've had 3 different ones so far and mine was built on January 25, 2006. The first version was the one that most if not all of us started with that shifted into 5th and locked up the TC in the late fifties. Production of US CRD's for the most part were finished before the reflashes were released. The first reflash caused third party scanners not to work and this one was before the offocial f37 and it came out in June 06. The third one, a offocial recall F30 fixed that and gave it f37. And they gave it another F37 when they did the ball point and heater motor recalls. They all have a little different shifting points but the top one remained the same after the first neutering reflash. My vag-com can identify the software version of both the ECM and TCM

RJM · **Posted:** Fri May 15, 2009 9:25 am

Quote:

As a side note those produced after 11/25/05 have a newer TC and only got a firmware flash with F37 :cry:

A Royal Flash :roll:

[/quote

]

If I understand this correctly, my jeep should not be F37 (build date 10/05) Why does it shift like it is F37?

To F37 or not to F37? That is the question...

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