Jump to content
Ultimate Subaru Message Board

Resistor getting hot 99 Legacy SUS


Recommended Posts

i HAVE A 99 Legacy SUS 4 dr auto 2.5 . Have had for a few weeks had hard shift to gear 3. Even some time at high speeds up a mountain. Fluid is up where it should be. No leaks.I read about a dropping resistor that mounts on the right side strut tower. Found what may be it. Has a plug to one end. Part number is A15-000-R81. Am I looking at the right part or does this have any thing to do with my trans shifting ???? Maybe by chance some one here knows what this part is by the part number.And my part seems very hot to touch  when car is running.

Link to comment
Share on other sites

+1 to everything he said.

 

i've never seen/heard of those resistors failing.   that it's hot almost suggests it's working?

 

you could try unplugging it and seeing how it drives.  some folks in XT6 and SVX world would disconnect or bypass them to sharpen up shifting. for a time there was even an aftermarket add-on the SVX crowd like to get to replace that resistor and firm up shifts.

if nothing changes when it's unplugged - maybe it is faulty.

 

they never fail so someone with a parts car could sell you one to avoid new costs.

Link to comment
Share on other sites

Those transmissions tend to slam into 2nd when accelerating at a low speed, like through town or a parking lot. They also like to slam into 3rd. You actually can adjust the 3rd gear band and the brake band from outside the transmission. There are two adjustment nuts on the driver's side of the transmission. I can't remember the exact sequence, but it's detailed in the FSM. Adjusting the bands and doing a fluid flush with filter change really helped my 98. With 265k miles it shifted like brand new.

Link to comment
Share on other sites

Just following the thread 'cuz I have a 99 sus w/at, I have the "won't shift/accelerate" problem on the first start-up of the day. I drive it for a minute or two and after the first successful up-shift it is fine for the rest of the day. Forum searching seems to support an internal gasket leak that doesn't allow enough atf to flow until the pressure builds. I wonder if the adjustment mentioned here will help(?)

Link to comment
Share on other sites

Just following the thread 'cuz I have a 99 sus w/at, I have the "won't shift/accelerate" problem on the first start-up of the day. I drive it for a minute or two and after the first successful up-shift it is fine for the rest of the day. Forum searching seems to support an internal gasket leak that doesn't allow enough atf to flow until the pressure builds. I wonder if the adjustment mentioned here will help(?)

 

In 99 they changed to a slightly different setup in the valvebody, and IIRC it has an issue with the o-ring around the reverse piston. This causes low transmission oil pressure and eventually causes it to stop working. People say that Lucas trans-x helps fix it, I've never tried that, though.

A friend of mine who spent years at a subaru repair shop said it's possible to fix without dropping the trans, but have fun there.

The issue is autos from 99-01.

 

I'm not sure why you're deadset on the resistor, I've never heard of that failing.

  • Like 1
Link to comment
Share on other sites

To test a resistor, you need an ohm meter to check the resistance. Resistors either have their value printed, or are color-coded with striped bands. They will either print the tolerance value i.e 5%, 10%, (in letter form like "K" or "J") etc. or it'll be incorporated into the striping. For example: a 1.5 ohm resistor with a 5% tolerance, means the value can be 5% +/- and still be in an acceptable range. If the value is way off like 25%, then it's bad. 

 

To actually test a resistor, you MUST break it from the circuit to check it's value, otherwise anything else in the circuit will alter the readings. You only need to pull one leg out of the circuit to test a resistor or remove the entire thing. They are NOT polarized, so orientation isn't an issue. Resistors can drift with age and temps, but they typically either work or they don't. When they go bad, they typically burn out. The fact yours is getting hot, suggests it's probably doing it's job. If you did end up replacing it, find one at a bone yard as there's too much for someone "new" to them to mess up with going aftermarket, especially if you aren't 100% certain of the composition, wattage rating, value, etc.

Edited by Bushwick
Link to comment
Share on other sites

SUBARU Automatic Transmission Solenoid A Dropping Resistor

July 2, 2011. Author: Lewis Werner

The SUBARU automatic transmission dropping resistor is connected in parallel with duty solenoid A. SUBARUAutomaticTransmissionDutySolenoidADuty solenoid A regulates the Subaru automatic transmission fluid line pressure. Like most of the transmission solenoids, duty solenoid A's duty cycle is varied by the transmission control unit (TCU) to control the line pressure.

The dropping resistor works with duty solenoid A in regulating the automatic transmission fluid line pressure. This resistor keeps a certain amount of current flow through duty solenoid A during the 'OFF' portion of its duty cycle. So in other words, duty solenoid A is never fully 'OFF'.

The dropping resistor is located on the right front shock tower, near the MPI (multi-port injection) fuel system dropping resistor. The photos at the right depict the Subaru automatic transmission dropping resistor.

If this resistor fails open, becomes disconnected, or has its wiring severed, one result might be increased shift shock. The reasoning behind this is that without the resistor in the circuit, the line pressure may be higher, since without the current passing through solenoid A during the 'OFF' portion of its duty cycle, it will tend to close further, and thus not bleed off as much pressure from the automatic transmission fluid pump.

If the resistor fails open or is disconnected, it should cause the ATF temperature lamp to flash 16 times on the next startup, since the TCU would be able to see electrically that the resistor is open.

This resistor was used on the SUBARU 4EAT phase I and 4EAT phase II automatic transmissions. It may also be used on the 5EAT though I have not confirmed it.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...