XSNRG Posted December 29, 2003 Share Posted December 29, 2003 I'm getting ready to put a new trans in my ebay XT-6. I pulled my '90 Loyale turbo up to the shop today and in the wet grass it will only spin one front wheel. Even after spinning for several seconds the rear would not kick in. Is the trans toast or could it be something repairable? Quote Link to comment Share on other sites More sharing options...
Skip Posted December 29, 2003 Share Posted December 29, 2003 XS, the rear drive is controlled by the TCU (Transmission Control Unit). In the tailshaft is a duty solenoid (Duty Solenoid C) which when it gets a signal from the TCU drains the hydraulic pressure from the engagement clutch pack. So if you have a constant signal to the DS C, the rear drive never engages. The TCU compares the two VSSs (Vehicle Speed Sensors) to determin when to release the pressure. There are fail safe modes if one is bad. The "POWER" light will flash at start up if the TCU sees a problem. The TCU can be put in diagnostic mode to find out what is wrong. Note: Newer versions of the FT4EAT have a place for a fuse under the hood, behind the pass side strut tower. The Loyale may have this holder, it will say "FWD" on the cover. 15 amp fuse works fine. This is for 2wd dyno testing. It also can be used for rear wheel down towing if the engine is allowed to run. (The pressure must be present to keep the rear drive disengaged) You should not have a fuse in the holder. The fuse signals the TCU and in turn it sends a signal to the aforementioned DS, thus opening the drain and disengaging the rear drive. These also had a problem with the seal at the rear output shaft. This problem would allow the hydraulic pressure that locks the rear drive to leak by and therefore not lock the rear drive. A new tail shaft with a modified bearing is the fix for this aliment. Recently several people have been talking about the FT4EAT on the new gen board, if you would like to read more about it, here is one of the posts http://usmb.ultimatesubaru.org/forum/showthread.php?s=&threadid=9139 Hope it's just the fuse in the holder Quote Link to comment Share on other sites More sharing options...
bushbasher Posted December 29, 2003 Share Posted December 29, 2003 on my 88 or 89? gl10t when you pull the fuse it went into 2wd, and you're saying it goes into 2wd when you put the fuse in? My mind could have slipped though I suppose. I just remember a cap that said "2wd" with a fuse underneath Quote Link to comment Share on other sites More sharing options...
XSNRG Posted December 30, 2003 Author Share Posted December 30, 2003 Thanks for the very useful info. I checked and there is no fuse, doh. I looked generally at the wireing harness and connectors and everything looks OK. I will investigate further and post back. Quote Link to comment Share on other sites More sharing options...
Skip Posted December 30, 2003 Share Posted December 30, 2003 XS, you say "I checked and there is no fuse' I ask this as my 89 FT4EAT has no fuse "holder" Some early models did not come equipped with the provision for putting them into 2WD. I looked all over mine with no joy- then I read some more. Did you find no fuse in the holder or no fuse holder? Which bring me to BushB's comment, my brain is lame I thought these said "FWD" but no doubt they said "2WD" on some models. I do know the addition of the fuse does force the car to ignore the VSS signals and run in 2 wd only. If you venture to the thread I posted or take a minute to do a search on the new gen board for "duty solenoid" or "binding" You will find this trick used to a) improve fuel economey (this is questioned) release the binding some FT4EAT cars expierence, by disconnecting the rear drive I do not have an owners manual, but I believe it is covered in it. XS, if you would like, I can find the color of the wires to the connector for DS C on an 89. By disconnecting it you can prove the brain is not to blame. I still need DS A, if you turn one, thanks Quote Link to comment Share on other sites More sharing options...
bushbasher Posted December 30, 2003 Share Posted December 30, 2003 Actually your probably right, it probably said fwd, as it was like the little "fwd" logo that you see on a dr shift gate. Though I must be remembering it backwards, mine likely went into fwd with the fuse in as you say. My friend actually discovered it and showed me later, before the car switched hands to me, and then I wired an in-dash switch to it, but I'll rely on what you say. Quote Link to comment Share on other sites More sharing options...
XSNRG Posted December 30, 2003 Author Share Posted December 30, 2003 Mine is a '90 Loyale and it does have a fuse holder with no fuse in it, I'm pretty sure it says FWD on it. If you have the wire color, that would be great, not sure if it's the same '89 to '90? I could use the colors for a '90 Loyale and a '89 XT-6. If it's not the brain then it's the DS? Or toast clutches? Either/or? If it's the DS C, maybe I can use the old one from the XT-6? Does towing them on two wheels destroy the transfer clutches? I did read the other thread and found it usefull. Have not done any additional serches yet. I will have the old trans from the XT-6, forward clutches and probably transfer clutches shot. If the trans is not worth re-building, I could turn you on to the DS A. thanks Quote Link to comment Share on other sites More sharing options...
myossfeece Posted December 30, 2003 Share Posted December 30, 2003 I have noticed that in my 87 RX it too has the fuse holder in it but nothing seems to happen when a fuse is put in, no dash lights saying 2wd or fwd. It doesn't seem to make a difference in my tranny. Yosh has a 90 legacy sedan that has a fuse holder and when the fuse is inserted sure enough a fwd light comes on the dash to let you know that awd is disengaged. Quote Link to comment Share on other sites More sharing options...
bushbasher Posted December 31, 2003 Share Posted December 31, 2003 it might disable use of the difflock? cause yours just has a center diff no electronic clutch crap Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.