trans won't shift by itself

[jgbailey57]

hello, newbie here. i have a 94 sho and am having tranny problems. if i put it in drive, it starts in drive, put it in second it starts in second, put it in first it starts in first. it will only upshift or downshift if i manually shift it. overdrive doesn't work either. any ideas on where to start? thanks in advance.

 

[Chris Benvie]

I would start with the ECU. But it sounds as if your trans is junk.

 

[RJ-92]

I would start with the ECU. But it sounds as if your trans is junk.

^^ What he said.

PM me if youend up needing one.

 

[jgbailey57]

the trans is electronically shifted right? all the gears are strong, no slipping. if it was a regular axod i'd probably look at the valve body. i was thinking ecu also. where is it located? is it the box on the front left of the car on the top of the core support? do you have a tranny or an ecu?

 

[James Downing]

if i put it in drive, it starts in drive, put it in second it starts in second, put it in first it starts in first.

I dont see a problem there... what do you mean by it starting in drive? do you mean 1st gear? and it wont shift into 2nd gear while in D?

 

[jgbailey57]

no. it starts in whichever gear i put it in. just like a manual. put it in 3rd and it's in third. pretty sluggish starts but it moves. not good on the clutches though. i can start in 1 and move to 2 and 3 manually just fine and down shift the same way. but it's an automatic, it's supposed to do it by itself.

 

[James Downing]

So, when you put it in D, with O/D on, it starts in 4th gear?!?

When you Stick it in D with the O/D off, it starts in 3rd...

and then 2nd in 2nd, and 1st in 1st...

Very strange... indeed

 

[jgbailey57]

pretty close, but it has no overdrive. that's controlled electronically isn't it? i'm pretty sure it's an ecu. it's either that or a bad connection. probably ought to start there i guess. where is the ecu located on this car?

 

[jgbailey57]

ok. i've been doing a little searching and it looks like the d4u1 is a popular trans mod. does it control the shifting or is there another computer that controls it? i remember checking the codes once a while back and it said something like "no trans communication" or something to that affect. there were a bunch of other codes also. i should probably hook up the old scanner and do some research on the codes.

 

[CheckerSHO]

The computer controls the transmission. The trans is probably operating sans electronics, so the shift solenoids are not working to shift it. Check the main connector on the trans, it may be disconnected.

 

[Axianator]

Out of curiosity, have you checked your VSS and it's connector?

As CheckerSHO has noted, the PCM (or EEC) is the sole, primary device that controls the tranny on the Gen 2 ATX. I would definitely start by inspecting yur tranny wiring harness (which is prone to failure on some Gen 2's) as well as any stored codes that you have. Also check your VSS (and connection) as noted and let us know what you find.

 

[revhardSHO]

How many miles on your ATX?

How does the fluid look on the dipstick? You can also smell it. If it smells burnt your going to need an overhaul.

 

[jgbailey57]

i finally fixed the problem. it ended up being the d4u1. i got lucky and found one in a junkyard. thanks for the help.

 

[jgbailey57]

oops. posted too quick. looks like it's starting to have problems again. scanned it and got codes 176 332 542 543. anybody know what these are off the top of your head? i remember a post or something that had all kinds of information about them. i'll do a search but if you find it faster than me let me know. thanks again.....never mind. i found the codes i was looking for at midwestsho.com i'll still take any suggestions on my tranny though.

 

[Rogue10186]

scanned it and got codes 176 332 542 543.

Code # = Definintion = what it really means
176 = Oxygen sensros indicate lean = you need new o2 sensors
332 = insuficeint EGR flow = EGR passage, across from the throtle plate, inside the intake is proly stopped up w/ crud, you need to clean them
542 = fuel pump secondary circuit failure = i dunno, never had it
534 = fuel pump seconday circuit failure = i dunno, never had it

Your first two codes are very common problems w/ the SHO, if you have any codes dealling w/ the Tranny they should be the 6##'s,

There are many ways of dealling w/ the EGR, look in a thread started by VTSHO named, "Check Engine Light with EGR Error Code," should be just below your thread, I told how I cleaned the EGR. There are other ways though, but the quickest is the method I explained.

You can find lots of info about SHO maintanence at www.shotimes.com

 

[jgbailey57]

did another scan and came up with code 645 - incorrect gear ratio obtained for 1st gear. it doesn't have the same problems i started this post with. last night i drove it and it was fine. i drove it today for about 5 miles on the highway no problem. waited for about 10 minutes while picking up my brother then got back on the highway. i hit the on ramp and hammered it. it went to 6000 but wasn't moving very fast. it was like it was slipping really bad. i just feathered the throttle and it was fine but now it starts in second gear instead of first, actually, it feels like it's in more than one gear at the same time. i'm gonna change the solenoid and see what happens. has anybody done this job? does the tranny have to come out? could it possibly be the vss? thanks for the egr info too.