88 to 94 A4LD Tranny Swap Issue | Ford Explorer Forums - Serious Explorations

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88 to 94 A4LD Tranny Swap Issue

Mr.Foss

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Joined
June 25, 2008
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City, State
San Diego Cali
Year, Model & Trim Level
1988 Ford Bronco 2
Hello,

I am trying to get some information on a A4LD Tranny i bought and put into my 1988 Bronco 2. My last Tranny went out so instead of having it rebuilt, I just went out and bought a A4LD tranny from a 94 Ranger that had been rebuilt less then a year ago for $250. I put it in and 1st, 2nd, and 3rd have awesome power, but it will not go into overdrive. I rechecked the wires that go to the tranny and everything looks good. I was wondering if it could be a bad solenoid or electronic issue.

Does any1 know if this 94 tranny will work with my 88? the 88 had a 3 plug wire just like the 94. Everything is the same except there is no dummy transfer case with this new tranny. My truck is a 2wd and i guess ford put dummy transfer cases on all bronco 2's. there was a speedo cable and a 2 wire cable that went to the transfer case. im thinking the 2 plug wire was just to notify that you are in 4wd. I had an aluminum driveshaft made that was 8 inches longer because the new tranny didnt have a transfer case.

also i had an issue after i put the tranny in that it wouldnt start. It ended up being a fuseable link under the hood that popped. so i replaced that and it fired right up. I have 3 relays under the hood. A gray 1 for the computer, a green 1 for the fuel pump and i have a black 1 that i am not sure about. is there any chance a relay or fuseable link popped? and could be the reason it is not going into overdrive?

If i can get a quick diagram or explination on the wiring that goes into the tranny from the relay down to the tranny i would greatly appreciate.

Thanks Again

Mr.Foss
Stuck in 3rd kinda guy.
 



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Where the transmission was just installed, the first thing I might check is if the selector is properly adjusted so the OD position on the dash does indeed correspond to OD at the transmission. I could see those symptoms being caused by you thinking it's in OD but the transmission is seeing D.

Second would be to double check the wiring. I've found the wiring diagrams in Chiltons (see the vehicle repair guides at autozone.com for electronic versions) adequate for the 3-4 shift solenoid and TCC solenoid circuits.
 






The dash does not has an od light. it never had a light that came on to show it was in od. I went threw the gears and adjusted the shifter. ( am gonna pick up a new b&m shifter in the next day or 2) . when in drive i move the shifter up a tad which should be od, then move it a little more and it goes into neutral.

I double checked the wires and spliced them correctly. next i need to do is check the voltage going to the solenoids. do you know if there is a fuseable link and or relay inbetween the tranny and the computer?
 






I may be way off here, but I "think" i remember one of the differences between early a4lds and new a4lds was the electronic controls. I Know the '92 has 3/4 shift and TCC (lockup) controlled by the pcm..

It grounds (not exactly ground, but ground through the pcm) the solenoid to allow the shift.

I don't know if this has any affect on putting this in an '88 but I figured it was worth mentioning..

BTW.. for testing I did manually ground my solenoids on our '92 (I diconnected the harness from the pc so I didn't shove a ground to the pcm) and when I grounded the wire for the solenoid I could control my 3/4 and my TCC.

~Mark
 






To my knowledge, there is nothing but wire between the solenoids and the PCM. As noted by Maniak, they are ground side switched circuits.
 






my 2 older trannys had a dummy transfer case with a speedo cable and a 2 wire connector connected to it. do you guys think this might be the issue why it is not allow the od solenoid to kick in? i know right now i dont have a speedometer or odometer working.. and i know the speed control is not working... but could this possibly cause the od to not work aswell??

I have some Stone Beer i will send out to any1 that can answer this question that either knows about this or has had this happen before ..

Mr.Foss
 






Welcome to this forum! Check the VSS (vehicle speed sensor).
 






Arguably the most important input in the computer's decision to shift into 4th gear is vehicle speed. In going from a 4wd tranny to a 2wd tranny, the VSS should have moved from the transfer case to the tailshaft housing of the transmission. Did this happen? If not, then that could explain why it won't shift into 4th gear.
 






thank you for the welcome.. the new 94 tranny does not have a hole in the tailhousing, it is sealed from the factory which leaves me to beleive it is all electronic controlled. looks like ill make a trip to the junk yard and find a tranny with a hole in the tailhousing with the internals to hook up.. and see where it leads me..
 






Check EBay. They appear from time to time.
 






You need a speed sensor of some sort
You need to convert your A4LD to use the 2wd tailhousing with the VSS

I did something VERY similar
I added a VSS to my manual transfer case that was not equipped with one.
I sourced the parts online, had them shipped and then found that the output shaft simply needed a check ball installed in order to retain the VSS drive gear.

After 2-3 hours with a carbide bit and a high speed dremmel I was able to bolt up the VSS. Cutting a ball bearing size dimple in a harded output shaft and getting it 100% in the right spot and the right depth was fun!

You may have to do this exact thing to the output shaft of your 2wd a4ld once you get your new tailhousing with VSS port
You will need:
VSS
VSS drive gear (likely rob from your old dummy t case)
tailhousing with VSS provisions
the correct speedo gear for your tires/transmission

then you should be golden!

tailhousing.jpg


ballbearing.jpg


bbspeedo.jpg


thread these pics come from are in my sig, AWD to 4x4 conversion

Good luck! I suspect you will finally have overdrive when you get the VSS talking to the truck and PCM...
You did install a kick down cable also correct?
 
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Yes the 94 tranny i got had the same setup on the linkage as the older 88 and 87 tranny, so the kickdown is hooked up and works. If this Works man i will Buy You a Crate load full of Stone Brewing Company beer made in San Diego lol... Wish Me luck and Thank You for This Information.. Much Appreciated...

Mr.Foss
 






I made it work, I had too! The t case I had for my 96 Explorer had 300 miles on it, came from a 98 F-150 and I got it for $100 from my buddy..

It was going to work even if I had to fab my own speed sensor on the driveshaft flange....LOL
 






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