'97 Ford Ranger, 3.0L, V6, Auto Trans Problems?

[gijoecam]

Glacier991 is the man on this stuff, i dont know why Bent Bolt is arguing with him on this.

They're not arguing, they're entertaining discussion on how the system works... It's a perfectly legitimate (not to mention civil and relevant) to the discussion. We're always trying to further our knowledge of how the system works. Since none of us designed the system, reverse-engineering the operational theory is no small task. It would be nice if there was a tech support person at Ford we could call and say, "Hey, explain how this thing works"

Now, just going back to some of the basics of the trans operation, I believe that if it was a band application issue, it would affect both forward AND reverse as the reverse/low band appears to be one in the same:

Page 307-01B in the service manual

Apply Components

....
Band — Low/Reverse
For component location, refer to Disassembled Views in this section.
Hydraulic pressure is applied to the front side of the low/reverse servo.

• This pressure causes the servo to stroke and apply force to the low/reverse band.
• This action causes the low/reverse brake drum to be held.
• The low/reverse band holds the low/reverse brake to the case in 1st position and reverse gears.
• This causes the low/reverse planetary assembly to be held stationary.

Could it be a forward-clutch-specific issue? (admittedly, I hav eno idea what those could be...)

Clutch — Forward
For component location, refer to Disassembled Views in this section.
The forward clutch is a multi-disc clutch made up of steel and friction plates.

• The forward clutch is applied with hydraulic pressure and disengaged by return springs and the exhaust of the hydraulic pressure.
• The forward clutch is applied in all forward gears.
• When applied, the forward clutch provides a direct mechanical coupling between the input shaft and the forward ring gear and hub.

• 
  

Also saw this chart, which I believe one of you was referring to:
(sorry about the formatting... the chart didn't copy well...)
Diagnosis by Symptom Index
ConcernsRoutinesElectricala Hydraulic/ MechanicalEngagement Concerns: No Forward Only201301No Reverse Only202302Harsh Reverse Only203303Harsh Forward Only204304Delayed/Soft Reverse Only205305Delayed/Soft Forward Only206306No Forward and No Reverse207A307ANo Forward in (D) Position and No Reverse207B307BHarsh Forward and Harsh Reverse208308Delayed Forward and Delayed Reverse209309


I believe the problem falls under the delayed/soft forward only section, right?

Still trying to figure out where to go from there....

edit... Just discovered the scroll wheel LOL!

Scrolling down to sections 204 and 304, for the electrical stuff, it does suggest the wiring harness, internal harness, PCM, VSS, TP, RPM, and EPC solenoid as possible issues.

On the hydraulic side, it goes into incorrect pressures, issues with the main control assembly (including screw out of torque, gasket damage, separator plate issues, EPC solenoid issues, the reverse modulator valve, forward modulator /EPC boost valve, forward engagement control valve, spring, or bore damage), or the forward clutch assembly.

I'm not seeing any reference to the DTR sensor in there. I believe the DTR sensor is used to feed the PCM directly, not the transmission directly:

Digital Transmission Range (TR) Sensor

The digital transmission range (TR) sensor is located on the outside of the transmission at the manual lever. The digital TR sensor completes the start circuit in PARK and NEUTRAL, the back-up lamp circuit in REVERSE and the neutral sense circuit (4x4 only) in NEUTRAL. The digital TR sensor also opens and closes a set of four switches that are monitored by the powertrain control module (PCM) to determine the position of the manual lever (P, R, N, D, 2, 1).

I couldn't find any specific references to what actions the mechanical link on the trans itself does, aside from engaging and disengaging the parking pawl.

Not sure if any of that helps shed some light on the discussion, or if it just muddies the waters even further....

 

[gijoecam]

Just to catch the eye of the original post, Here's something simple to try: When it won't engage, manually shift the lever to the '2' position and see if it engages. If so, then that would definately narrow it down to a 1st-gear-specific issue... although I admittedly have no idea where that leaves us for the next step...

-Joe

 

[BrooklynBay]

Joe, the link which says "disassembled views" doesn't work. Could you correct this?

 

[Bent Bolt]

Glacier991 is the man on this stuff, i dont know why Bent Bolt is arguing with him on this.

Because I do this for a living. Ford factory trained and very good at what I do.

 

[Bent Bolt]

Bent Bolt - I am looking in the diagnosis by symptom pages as well. "Engagement Concerns - No Forward Only" under 301 - Hydraulic/Mechanical Routine. Second listing under Shift Linkage.

It is a little confusing.... on the one hand it suggests linkage issues, in which case the manual valve may not in fact move to allow fluid passage to cause forward engagement, just as you suggest... but then it goes on to suggest as a possible component "DTR sensor out of adjustment". That is the part I find a little confusing. I do understand what you say about the mechanical interconnect of the shift lever to the manual valve not involving electronics. Thoughts ?

I have been thinking about why the TR is mentioned as a possible cause of no forward. It's not the electrical issue that the engineers are after, it's the phsyical failure of the TR. What if the TR seized solid?? You wouldn't be able to move the shifter, possibly can't move it into Drive, therefore no forward!!!

Gotta think like an engineer sometimes.

 

[Glacier991]

Ok thanks.... I think that is about the only likely explanation.

And again, for those who don't realize, Bent Bolt is a trained FORD tech, his knowledge base FAR FAR exceeds mine. I think we are lucky to have someone with his expertise on here. We have had similar folks here in the past, but it has been a while since we have had a regular FORD tech in our midst. I do appreciate the esteem which some of you hold me in, however. Thanks, not sure I deserve it.

 

[Tucson_girl31]

Hey guys -

Just an update. We had the transmission flushed and new fluid put in, and the filter was changed. The guy said the filter didn't look "bad" and that there were no metal shavings in the pan.

As far as all the info, y'all have lost me completely at this point. The best we can do is see if this fluid flush/change helps and if not take it to a tranny shop. No offense to Bentbolt (I wish you lived here!), but I am reluctant to go to the local ford dealers here. We have not had good experiences with them. At least in their sales departments, their tactics are just plain seedy.

Would it be insulting to print out this thread and present it to the techs at the tranny shop? Just as useful info? Would a rebuild address all these issues or could we end up having the thing rebuilt only to discover something else was causing the problem?

 

[Glacier991]

That info helps. Let us ponder it a bit further here before we send you off to the "wolves" so to speak...

But as we do, let me explain to you and others a point of view from the perspective of a shop... and Bent Bolt can either correct me or support me. Shop labor isn't cheap. We on the board here can think, ponder and suggest "possible" fixes short of a rebuild.... saving you a lot of money if we are right.... But the guys who have to "try out" those fixes still charge at the shop's hourly rate.... soooo...Let's do a just fer instance scenario...

Let's assume that you have a puzzling problem. And let's assume that it is "possible" that a valve body rebuild might solve it, (and maybe not....) but they try it out....at shop labor rates... and $400 to $600 later you find out that didn't solve the problem. Next they say, "Well, looks like a rebuild, and that will be $2000." YOU are not going to be happy they seemingly "wasted" $600 of your money to "Try" and fix it, and failed.... and still want to charge you for the rebuild.

That is why even honest shops, when faced with a tough diagnosis, sometimes opt for a full out rebuild.

(I will not even go there with the dishonest shops that quote a full rebuild on a clear cut easy fix that is obvious).

The very best shops, faced with this, will do the VB work and try that out, and failing that will credit it against a full rebuild. That is rare though, but fair.

 

[Tucson_girl31]

Gotta think like an engineer sometimes.

Ha! Ain't that the truth. I work with lots of them.

I understand, Glacier. I realize how complicated this stuff is, and I have no problem paying mechanics for their labor. It's just finding a shop that you feel comfortable with that seems so difficult. And we had such icky experiences with the Ford/Mazda dealers when we were looking at Escapes and Tributes that I just don't want to go back. We are just on a tighter budget these days since my husband quit his job 6 months ago to go back to school. If only this problem could wait until August when our CD is up and we have more cash...sigh.

Thanks again. Can't wait to hear your thoughts on the lack of metal shavings. This stuff is fascinating. Wish I understood it better.

**Update** Well, perhaps the flush and filter change did the trick! The oil that was in there wasn't dark or dirty, but maybe the truck just didn't like it. This was the first morning in a long time that it shifted perfectly into D after he backed out of the garage! We'll keep an eye on it for now and see if the problem recurs.