OK, here goes! I just bought this truck thinking I'm getting a real good deal?! "91 F150- 4x4- XLT Lariat w/ 5.0 EFI & E4OD, Body in excellent condition "No Rust". I was told the transfer was locked in 4x4 low so I thought no problem? But after checking the transfer, I was able to shift it out of 4x4 into 2w/h so I thought I just made a heck of a deal?! WRONG!... tranny goes into 1rst gear no problems, but then it reaches about 10-15 mph & engine just revs to around 3500 & then Bam! shifts to 2nd, same thing again 25-30 mph & Bam, hits 3rd, & thats as far as it will shift, 45 mph & tach is reading 40-4500rpm's I tried letting off the gas thinking it would shift but it just acted like engine brake was on? OK, so replace MLPS, Same thing, no change at all? Next I removed the plug wire from the OSS {output shaft sensor} Now the tranny shifts 1-2-3 Hard? Next I removed the plug from the VSS on the rear axle, No change there, makes no difference if it's connected or not? Also after I first start the truck, the check engine lite comes on real dim after about 10-15 sec, then after 25-30 sec. the rear ABS lite comes on bright? All the lites work on the truck & the brake lites aren't on untill I apply the brakes? I don't know if this is enough info for anyone to go on, but I'm hoping someone out here in fordland can help me?

 

45mph @ 4000+ rpm? That's not 3rd gear with an E4OD...sounds like you're still in 4LO. 3rd gear in my E4OD, even with a 4.10 rear is about 2800 rpm @ 65 mph.

Sounds like you have several problems.

Jason

 

my 91 did the exact same thing.. i replaced the worn plastic gear at the end of the speedo cable where it goes in the tranny (vss) half the teeth were shot. instantly cured the slams. yes i have e4od. it's an easy job and the part was a few bucks. good luck

 

That's what I'm beginning to find out! I took the front drive shaft out thinking if that was the problem it would make some kind of difference, but it doesn't? So after putting the driveshaft back in, I tried to pull up a little hill in my back yard in 2/w & the right rear wheel would slip, then I shifted to 4\L & walked right up it? So that appears to me that the transfer is working as it should?

 

yeah, go get the vss gear, 20 mins work and pretty sure, not positive, but your discription made the short hairs on my neck stand up because of the exact symptoms of what i went through

 

My speedo seems to be working correctly? It's smooth in it's operation? I'm wondering about the vss in the rearend, since it makes no difference if it's connected or not?

 

Did yours have the 2 wire connector also on the speedo cable? ...Reason I ask is because if I disconnect it, it will shift like...1-2-3 as soon as the rpm's get to 13-1500? If it's connected then it won't shift to 2nd till It gets about 26-28000 then it slams into gear?!

 

yes it does

 

OK, I went online to order the whole thing from advance auto but they didn't have it in stock, so I'll have to check my local parts house? Thanks much.... I'll post back when I get it & let you know if that fixed it.

 

the part is inside at the end of the speedo cable. just a little yellow plastic gear. $6-7. my local napa, advance and auto zone have 'em in stock. don't let them sell you a bunch of stuff you dont need.

 

I'm thinking of buying the whole thing, because I had it out already & the teeth don't look worn? & also my speedo doesn't seem to be messed up? I'm just gonna buy the whole thing. Advance auto parts list them for $31 & my local American parts wants $60!

 

Well I went & bought the ABS sensor, that took care of the RABS lite on the dash Also bought the "OSS" for the tailshaft that houses the speedo cable along with the new "Gear". That didn't solve my problem?... The "Check engine lite is still on real dim? So I guess the next thing is to try a TPS?

 

After replacing the MSLP on my E4od, Tranny seems to be running in between 2 gears? It's like when I take off in drive, it runs up to about 20 mph then it seems like it shifts into 2nd but it's not fully out of 1rst yet & the tach goes to 25-2800 before it actually feels like secong gear finally took over, then the tach drops back to 2000 rpm's, same thing with 3rd gear? I can get it up to 45-50 mph & the tach just keeps climbing & it's not going into 4th or OD. If I put it to the floor, it'll downshift to whatever gear I just came out of? It seems like the MSLP needs to be adjusted further counterclock wise than the slots allow it to go? I had the trans. shift lever in neutral when I replaced it & the dash indicator was in the correct position, I also tried rotating it clockwise & that made it shift way to late. My question is, could it be the TPS causing this? I tried disconnecting the TPS & that made it shift so hard the tires would bark in all gears!

 

you are reseting the computer after you change something, right?

if not, disconnect the battery for 10 minutes.

computer will have to relearn stuff so you need a short drive to do this.

 

Matter of fact I did, had to buy a new battery, so it was disconnected for a day? But thanks for the info.