01 Elantra cold tranny problems

[billmacleod]

I just purchased 2001 Elantra. Had a downshifting problem from drive to third. I didn't have anyone retreive any codes. Did a lot of reading and decided to replace the TCM and both the input and output sensors yesterday. Started driving and bad buck shifting from 2nd to third. CEL came on. Stopped, turned engine off. Started again and it was stuck in third gear. Turned it off again and started again, this time it ran good with CEL still on. Stopped and disconnected ground on the battery for 10 minutes. Connected the battery, CEL off and drove around for about an hour city and freeway and all was great. Thought that the TCM was just learning and all problems solved. Wrong. Started driving early this morning and same thing, bucked 2nd to 3rd CEL on. Drove a bit after turning it off a couple of times and all is well again with maybe a little slippage between 2nd to 3rd. The transmission fluid has been drained and filled to the HOT mark with SP111. Made an appointment at the dealer for Monday 9AM to have codes read. I have a feeling they will suggest a new tranny. Does anyone have any thoughts of anything to try? Any help will be greatly appreciated

[PLP]

I guess that if it was mechanical problem (transmission issue) it would be persistent. However, in your case it happens from time to time.

Is it all the time or only on cold? If cold - could it be wrong fluid? I do not know what specs it is as I had M/T.

[billmacleod]

Originally Posted by PLP

I guess that if it was mechanical problem (transmission issue) it would be persistent. However, in your case it happens from time to time.

Is it all the time or only on cold? If cold - could it be wrong fluid? I do not know what specs it is as I had M/T.

It's what the Hyundai website specifies for that car. I am going to see if I can buy a filter and drop the pan. Maybe it's got some gunk stuck to the filter and it needs to warm up to move it around.

[billmacleod]

Originally Posted by billmacleod

It's what the Hyundai website specifies for that car. I am going to see if I can buy a filter and drop the pan. Maybe it's got some gunk stuck to the filter and it needs to warm up to move it around.

Scratch that idea. It has an internal filter. You have to disassemble the tranny housing.

[billmacleod]

Originally Posted by billmacleod

I just purchased 2001 Elantra. Had a downshifting problem from drive to third. I didn't have anyone retreive any codes. Did a lot of reading and decided to replace the TCM and both the input and output sensors yesterday. Started driving and bad buck shifting from 2nd to third. CEL came on. Stopped, turned engine off. Started again and it was stuck in third gear. Turned it off again and started again, this time it ran good with CEL still on. Stopped and disconnected ground on the battery for 10 minutes. Connected the battery, CEL off and drove around for about an hour city and freeway and all was great. Thought that the TCM was just learning and all problems solved. Wrong. Started driving early this morning and same thing, bucked 2nd to 3rd CEL on. Drove a bit after turning it off a couple of times and all is well again with maybe a little slippage between 2nd to 3rd. The transmission fluid has been drained and filled to the HOT mark with SP111. Made an appointment at the dealer for Monday 9AM to have codes read. I have a feeling they will suggest a new tranny. Does anyone have any thoughts of anything to try? Any help will be greatly appreciated

I took it to the dealer this morning. The scan only gave the output speed sensor trouble code and no other codes. I asked if the replacement sensor could be bad. They said no. They said there must be a short in the wire harness. $2000.00 for harness and labor. My uestion was why only in the morning? They didn't know. So I decided to have the alternator and battery tested thinking maybe they may be bad and may be draining overnight. Nope. Both are good. Also the original problem of downshifting from 4th to third has gone away. Any ideas anyone?

[PLP]

hmmm - I would start over with simple things such as connectors. Loose connection, dirt, dust, rust... all of them will make any connection poor.

Follow the harness and test all points. You may also use ohmmeter to see if any short exists (I highly doubt though).

On a side note - not every problem is what it appears to be.

[santa06]

Replacing an entire wire harness because of one possible short; idiotic, time for another repair facility.

Chop off wiring 2 inches from output plug ; then find out what two pins on the ecm the two output wires on the sensor go to; solder and hear shrink and $5 worth of decent copper wire; covered with wire loom after for protection. An hours work for a decent auto electrical tec.

Had a Chrylser dealer try this on me for a Jeep O2 repair a few years ago; laughed in his face and asked if they replaced engines as well that needed spark plugs--never returned as a customer.

[billmacleod]

Originally Posted by PLP

hmmm - I would start over with simple things such as connectors. Loose connection, dirt, dust, rust... all of them will make any connection poor.

Follow the harness and test all points. You may also use ohmmeter to see if any short exists (I highly doubt though).

On a side note - not every problem is what it appears to be.

Thanks PLP and Santa06 also. Problem solved.
The connector to the output speed sensor was missing the clip and not making a solid connection. Tie wraps are great!!