42RLE (4-Speed) Symptom & Solution

[rwalshphoto]

So sometime about 6 months ago I started chasing a ghost of a problem with my car. At this time I had been going through a lot of changes with the tune trying to resolve some issues and thats when the problem started popping up. Oddly enough my friend Nate (BritishNate) was in almost the identical circumstances - similar mods, similar tune, same time frame, same symptoms. This ended up being a complete coincidence as far as I can tell at this point.

The Symptom:
At random speeds when the car would downshift it was like the transmission wouldnt engage - almost like pushing the clutch in on a manual transmission. It would happen at completely random times and at different speeds and in different gears. This would occur maybe once every other week or so. Sometimes it seemed to do it more if the car was under more load when I had more people in the car or stuff in the back.

Because of lack of funds I just dealt with it for several months not wanting to just blindly throw parts at it without a sure solution. Well, I came into a turn pretty hot the other day expecting to drift/power through it and the car dropped into the lower gear like it was suppose to, was in power and car was sideways and boom it does its shift thingy and all of a sudden no power to carry through the turn. Luckily nothing bad came of it but enough to make me take action to fix it - lol.

The Solution:
My first guess was fluid level and or the correlation with temperature changes - no dice. I spent quite sometime searching for threads on here and other forums and finally Nate found a hint in a old thread on another forum that pointed to the speed sensor. So I bought some from Ted and Jeff at AllUSA and swapped them out on saturday. There are two speed sensors - an "upper" and a "lower". Not knowing which was bad and not having a starscan to do the tests to find out I bought both.

These are the part numbers and prices:
4799061AB Speed Sensor $30.23
52854001AA Speed Sensor $25.71

The speed sensors look like little plastic cylinder with rubber o-rings on them to seal into the trans and they have a flange around the outside with a hole where it bolts to the side of the trans. Its took me maybe 10min to change both sensors. Only tool needed is an 8mm wrench - ratcheting wrench preferred. The back sensor has a small magnetic nose on the tip of it - mine had quite a bit of metal shavings.

So far the results have been far better than expected. Besides the fact that it hasnt done its weird disengage thing, the shifts seem to be more predictable and more accurate. It seems to have taken care of a couple other symptoms that I just wrote off. The car used to sporatically bog off the line, pretty much at least once every trip. So when I would go WOT on launch it would sit there and bog and when it got into the middle RPM range the power would come on like a light switch... almost like i was launching from 2nd gear. Hasnt done this once since I swapped the sensors. Overall the car is just more driveable. I really have no idea how much these speed sensors affect the actual TCM or whatever adaptives or anything else it may do with the inputs but its seems to have fixed it.

[todd0218]

interesting... seems there isnt a ton of knowledge on the 4 speed but this is interesting. Its a bummer you dont have a video or something to really visualize the car in its ill symptoms per say.

[MAGFX]

Good job, Ryan, on figuring out the problem.

[rwalshphoto]

I took a video a while back on my camera phone and you could hear the it downshift and the tach jump but the speedometer wouldnt move. When it would do this it would sit there and bounce on the "neutral" rev limiter until I would let off.

[BritishNate]

good write up ryan i will let you know when i have money to buy those....

[JarZ]

Yep the exact same thing happened to me a week after I bought the LHS (same transmission basically), but the car went into limp mode and mechanic said "you need a new transmission". So I went to dodgeintrepid.net with the code thrown by the car and voila - busted speed sensor.

$70 later, INCLUDING PARTS (I also did both sensors) it was good as new and has been running like clockwork since.
Ah the power of the internet

Glad you got it fixed.

[rwalshphoto]

Cool. Mine never threw a single code though

[Phil056]

Did you ever try and pull Fuse 11 to see if that remedied the issue? - I Guess since you haven't had any issues it was those parts, thanks for the #'s, saved them in my part list document.

[rwalshphoto]

Did you ever try and pull Fuse 11 to see if that remedied the issue? - I Guess since you haven't had any issues it was those parts, thanks for the #'s, saved them in my part list document.

I cant count how many times Ive pulled fuse 11 or reset the TCM by pulling the battery, etc since the issue started...mainly for other reasons but yeah...no help.

[SKULLBOY]

The car used to sporatically bog off the line, pretty much at least once every trip. So when I would go WOT on launch it would sit there and bog and when it got into the middle RPM range the power would come on like a light switch... almost like i was launching from 2nd gear. Hasnt done this once since I swapped the sensors. Overall the car is just more driveable. I really have no idea how much these speed sensors affect the actual TCM or whatever adaptives or anything else it may do with the inputs but its seems to have fixed it.

This is the exact problem I have had since my S/C install......Mine is a constant "bog" off the line............haven't had the downshift problem though........

I might have to try replacing those sensors and see if the gets rid of the bog off the line..........

[Zoban]

Sort of a thread jack but related ..

What options do we have for high Stall TC's in our 4spds ?

[rwalshphoto]

Sort of a thread jack but related ..

What options do we have for high Stall TC's in our 4spds ?

I dunno, I talked to Stu about it a while back and I think ProTorque can make one but I havent heard of anyone taking the plunge. I'd personally be worried something would give in the trans with hard launches but pay to play I guess.

[Zoban]

Hmm.. that sucks .. will have to keep eye out and maybe if $$ work out right be the first to plunge in on this one..

[Bryali]

Unfortunately, the swap for a 5spd is pretty involved and expensive. That's what I've gotten from looking around on here and other forums. Who knows, maybe someone will come up with a plug-and-play 5spd or a "built" 4spd.

[SKULLBOY]

Unfortunately, the swap for a 5spd is pretty involved and expensive. That's what I've gotten from looking around on here and other forums. Who knows, maybe someone will come up with a plug-and-play 5spd or a "built" 4spd.

Coming from a friend who works in a transmission shop, these transmissions are not cheap to rebuild.....you can almost by a brand new one for the cost of a rebuild..........

I asked Stu about the Interia 3500 stall TC for my 4 spd.......he told me not to bother........to blow up the 4 spd and replace it with the 5 spd and then get the highstall TC..........

I have a inquiry into a fellow forum member who works at the Brampton assembly plant to see exactly what is involved in converting to a 5 spd..........I know a wiring harness and TCM will be required along with the transmission itself........since the swap from 4 to 5 spd was a mid year change in 2006, it can't really be that much of a difference or difficult to swap, as you would think that they would want to keep things simple to keep running smoothly on the assembly line without a lot of indepth changes/interuptions..................