94 explorer A4LD problems

[Josh]

When this problem started, was it after a failed start followed buy a sputter or backfire through the intake. Usually when your truck backfires and blows off a vacum line, the motor runs crappy, but if you blow off the end at the modulator, its not as noticeable and will cause that problem. The only way to verify is to get under and feel behind the rear of the heat shield. This happened to me once.

 

[mechjames]

The problem began before I got the truck. Its still very drivable.

The motor does seem to surge a bit at steady throttle. I'm going to have to take a look at the vaccum line. See if its filling up with fluid, or if its come off.

Where is it again?

 

[BrooklynBay]

It connects to the vacuum tree.

 

[mechjames]

i've looked underneath while i was changing the flkuuid the other day, and didn't see any vaccum modulator on the transmission. its hidden above the catylic converter, isn't it?

also, i've checked all the vaccum connections on the intake tree, and I can't see any transmission fluid in them. I'm hoping its just disconnected at the transmission.

If it was a sticking governor, do you think a nice fresh fluid change might get it unstuck in a while? Or an addictive?

 

[BrooklynBay]

The modulator is inside of a heat shield so it's out of your view.

 

[wood1]

I pulled my governor yesterday, there was some noticable wear on it, as well there is a return spring improvement you can install to improve it's operation. I also replaced the weight with a 35mm. Check Glacier's VB rebuild

(http://www.explorerforum.com/forums/showthread.php?t=137972&highlight=valve+body+rebuild)

My transmission wouldn't shift into 2nd when cold, works perfect now.

Brooklyn suggested you adjust your kick down cable, and do a band adjustment as well. Try that first, they are easy to do, look at his "My list of useful threads" link in his signature, #19 and #45.

 

[mechjames]

i've been driving it around, and the transmission operation is the same. backing off the throttle to shift, and sometimes while cruising, it'll upshift, like its at full kickdown.

so i'm going to check the modulator hose, make sure its on there.

also where is the kickdown cable? i can see on the throttle body two cables, but i know one is throttle from the gas pedal and the other one has to be cruise control, right? usually the kickdown wire is at the throttle linkage

because it awfully feels like its at full kickdown, with the upshifting a lot earlier than expected

 

[mechjames]

aye its on the firewall right? hooked up to the gas pedal isn't it?

 

[mechjames]

alright, the vaccum line is on the modulator, i can feel it. when i adjust the kickdown wire, it seems to help it not slip out of gear as much, and it does help it shift at higher rpms, so i don't have to back off the throttle all the way. Maybe its just me, cause the difference was very little. I'm going to play around with the cable a bit. Do you think the kickdown cable may have slipped off the gas pedal?

If that doesn't help, a band adjustment may be in order? Also a stuck governor maybe?

 

[Josh]

I would pull that vacum line and make sure there is no fluid in the line. If there is then the modulator is bad.

 

[mechjames]

the modulator line to the intake is the one which has the bracket bolted to the upper intake? if so, then there is no transmission fluid in the line.

 

[mechjames]

today i decided to count the shifts. it's missing second gear, and just jumping right into third from first. even if i start out from 1st, then manually shift it into second gear, the revs stay at the same speed as in 1st. third is where it changes gear, because i can feel and see it.

So i'm going to try the band adjustment soon.

if it was a sticky governor it would be a delayed or no 1st to 2nd shift when cold, and right now i just don't have a second gear, no matter how long its driven.

 

[wood1]

Yeah, I'd adjust the bands and see if that helps.

 

[mechjames]

i've adjusted the bands, but at the same time, i changed out the fuel sending unit. i had problems with that, and haven't been able to drive it yet. tonight i'll take it for a test drive and report back what the results are.

 

[mechjames]

alright, adjusting the bands doesn't help me from the first to third issue, because i still have to back off the throttle to shift.

although....

if i manually upshift from third, back to second, it actually has a second gear. I know this because when i bring it down to first, it upshifts at the right time again when the speed is right.

so....

i'm thinking the valve body may need to be rebuilt. might as well put a shift kit in at the same time right?

won't be doing this for a few months though.

the only thing i want to try is replacing that vaccum modulator thingy. they're cheap, but it looks like a big job because of the catylic converter heat shield.

someone chime in. what do you think this problem is?

 

[wood1]

You might find it easier to get at the modulator from the interior. If you pull the carpet back you can go through the hole in the floor where the manual shifter would be if it was a manual transmission.

There is a thread recently where someone did just that... found it.

http://www.explorerforum.com/forums/showthread.php?t=203237&page=2

 

[mechjames]

alright, i've been looking around this site, and at the same time i change the modulator, i should change the servos at the same time, right?

also i've heard that my intermediate servo could be causing the problem.

one more thing i've noticed. second gear really isn't much there. sure i can upshift from Drive manually, and then the revs go up a whole lot. Almost feels like its not much better than first gear.

So this would be a servo problem?

 

[wood1]

If you manually select 2nd gear from a dead stop does it start off in 2nd? You can verify this by starting off then pulling it down into 1st, you'll feel it if it downshifts.

If you manually select 1st then start driving, shift into 2nd what happens?

Do I understand you correctly, in that when driving along in 3rd you can select 2nd gear and as you slow the trans will downshift to 2nd? If so it sounds as though the intermediate servo works...

 

[mechjames]

If i manually select 2nd gear from a dead stop it starts out in 1st. No downshifts until i select D (3rd gear)

If i manually select 1st then start driving, and shift into 2nd, nothing happens. it stays in 1st gear.

Yes it feels like driving along in 3rd and I select 2nd it upshifts to 2nd, unless its upshifting to 1st gear.

 

[wood1]

I sent you a PM dude, but it does sound like it's messed up. I just don't have enough experience to diagnose you problem. All I can do is read in the manuals and make suggestions. You may be right in saying you will have to rebuild your VB, I'd do everything outside that I could first, service governor, replace the modulator and servos then tackle the VB and hope for the best.

You should consider getting the ATSG manuals, they are extremely informative and available on EBay or transmission parts suppliers.

Good luck.