Ok. SO I have a 95 F150 that used to have a 8.5 Inch dif ( I think it was called that) with ABS and 308 gears

Today I swapped my dif out (it was howling) for a Ford 9 Inch dif with no abs and 350 gears in it.

After getting everything set up, the truck is doing some strange things.

1) The speedometer does not work
2) There is no first gear (it's auto, and it will drive as though it is in first, however when shifting down it doesn't seem like it goes there. It seems like the lowest it goes is second gear)
3) My O/D push button has a light that says "off" This light is flashing.
4) My ABS light is on, but that is because I don't have rear abs anymore.
5) When I spun out in the snow (on purpose) the truck did a 180 and when it was faced backwards it stalled out.

Any ideas on how to fix these problems?

Thanks SO MUCH!

Pete

 

You need to bring your truck into a shop that can read the transmission error codes. The O/D light is blinking because there is a problem with the transmission. It may be a bad sensor or it may be a sensor that is detecting a problem. This is a fairly urgent matter also. You don't want to drive too far with that O/D light flashing.

 

Well your o/d light could be on becuse of the speedo, or the problems with it not shifting to 1st gear, you will need to recalibrate the speedo anyway to compensate for the gear change. I'm not an expert but I thought your truck came with a 9" rear from factory??? or maybe a 8.8??

 

I would chack and make sure that the speed sensor and the wiring are good. The rear speed sensor can cause the speedo and tranny problems.

-Jon

 

most of your problems are caused by the missing speed sensor. The truck needs it. As far as your first gear problem, There is a gear for the speedo on the extension housing of your tranny. You need to replace it to correct for the change in gearing. I can't remember but I think it is 3% per tooth of the driven gear. But without the rear sensor I wouldn't count on the O/D, abs, and speedo working right.

 

you need that speed sensor!!!! It is what the ecm looks at for shifting, speedo & abs

 

Thanks a lot guys. greatly appreciated.

unlawful, nah it didn't come with a 9 inch.

Pete

 

You better stop driving the truck unless you want to buy a new tranny. The PCM relies heavily on the speed sensor to tell the tranny what to do. The previous owner of my truck took out the Ford 10.25 rearend and put a Dana 60 under it. Same deal as yours: no speedo, abs light on, tranny acted funny, etc. IT RUINED THE TRANNY WITHIN 1000 MILES. Bad for him, good for me. I bought the truck dirt cheap and already had another correct rearend. I am afraid your only option is to get another good 8.8 rearend.

 

good to know, from what the ford techs told me today, I can run the 9 inch as long as I get the speed sensor to run from the tranny..There is a plate covering the plug for it on the tranny they said.

I'll find out for sure

Pete

 

Did they clearly understand that this was a '95? The earlier (pre-92?) trucks had the Vehicle Speed Sensor in the tailshaft housing for the cruise control but used a cable for the speedo. The electronic speedo or PSOM relies entirely on the signal from the diff. The frequency of that signal is going to be very different from anything you can possibly get off the tranny tailshaft, assuming that you can cobble something together.

I wish you luck, you're going to need it.

 

Why didn't you just find another 8.8" rear end? I mean a built 8.8" can handle well over 500rwhp. If you needed new bearings, those are about $80 for a complete gear/pinion/carrier rebuild kit...

I am with StrangeRanger good luck.

 

Yah i was just looking at a website about a Mustang running under 10 second quarters with a 5.0 and no power adders. it had an 8.8 rear with a spool and 5.13 gears. if it can handle the 6500rpm launches from that thing, I think it will work just fine in my truck.