Speedo/Tranny?

Nixon1 · 01-19-2003, 09:17 AM

Ok, I was told this by my grandpa, who's gone through several Fords in his life.. The transmission uses the speedometer reading to determine shift points? This sounds kinda weird, and a little dumb to me, but I'm assuming he's correct because...my speedometer jumps all over the place..it's shot...and in Drive, with my foot to the floor, it shifts into 2nd gear at 3500 rpms. It's killing me. So, is gramps right? God I hope so. The speedometer is getting repaired in the next week.... Thanks everyone.

Nixon1 · 01-20-2003, 11:21 AM

Any takers? Just called a transmission shop and they told me this transmission doesn't use the speedometer at all....

cyberstang5.0 · 01-20-2003, 01:32 PM

The tranny will shift only at a certin pressure inside the valve body. It does not use the speedo to determine the shift points. The tranny does have a gear inside of it to turn the speedo cable which moves the speedometer. That might be the way the older trannys were built (not sure on that one) but that is not how the newer ones are run.

Nixon1 · 01-20-2003, 09:27 PM

Thanks... Last Ford my grandpa owned, besides his late 80's T-Bird was a Torino....that was a WHILE back, so... The car goes in the shop to have the tranny fixed...I'm guessing it's just a cable causing hydraulic pressure to be totally out of whack..hopefully it isn't doing too much damage, but I've hardly driven the car at all, and I'm going easy on it when it gets legal tomorrow.. Also the speedometer is gonna be fixed hopefully, whether it's a gear or just the cable needs a good lube. And they're servicing the differential too..opening it up and inspecting to see whether the gears really are 3.73, if they're not they MIGHT throw a 3.73 set in, and they're gonna fill it back up with brand new fluid, and friction modifier. So...knocking a bunch of birds out with one stone. I wanna get this car running cherry, because so far, I'm in love with it. I don't need any surprises!

01-19-2003, 09:17 AM	#1
Nixon1 Registered Member Join Date: Jan 2003 Location: Palm Bay, FL Posts: 432	Speedo/Tranny? Ok, I was told this by my grandpa, who's gone through several Fords in his life.. The transmission uses the speedometer reading to determine shift points? This sounds kinda weird, and a little dumb to me, but I'm assuming he's correct because...my speedometer jumps all over the place..it's shot...and in Drive, with my foot to the floor, it shifts into 2nd gear at 3500 rpms. It's killing me. So, is gramps right? God I hope so. The speedometer is getting repaired in the next week.... Thanks everyone. __________________ '91 Mustang GT 5.0 AOD Daily Driver Current stats: NEW 302 short block, E-303 cam (@.050, 220/220, .498/.498, 110 degrees), 1.6 roller rockers, Performer RPM heads (aluminum, 1.9/1.6, 60cc chambers), Cobra intake, Granatelli 75mm MAF, Billet AFPR, Equal-Length Shorty Headers, Off-Road X Pipe, Flowmasters, 4.10 POSI 13.73 at 103.8, ~2.2 60'

01-20-2003, 11:21 AM	#2
Nixon1 Registered Member Join Date: Jan 2003 Location: Palm Bay, FL Posts: 432	Any takers? Just called a transmission shop and they told me this transmission doesn't use the speedometer at all.... __________________ '91 Mustang GT 5.0 AOD Daily Driver Current stats: NEW 302 short block, E-303 cam (@.050, 220/220, .498/.498, 110 degrees), 1.6 roller rockers, Performer RPM heads (aluminum, 1.9/1.6, 60cc chambers), Cobra intake, Granatelli 75mm MAF, Billet AFPR, Equal-Length Shorty Headers, Off-Road X Pipe, Flowmasters, 4.10 POSI 13.73 at 103.8, ~2.2 60'

01-20-2003, 09:27 PM	#4
Nixon1 Registered Member Join Date: Jan 2003 Location: Palm Bay, FL Posts: 432	Thanks... Last Ford my grandpa owned, besides his late 80's T-Bird was a Torino....that was a WHILE back, so... The car goes in the shop to have the tranny fixed...I'm guessing it's just a cable causing hydraulic pressure to be totally out of whack..hopefully it isn't doing too much damage, but I've hardly driven the car at all, and I'm going easy on it when it gets legal tomorrow.. Also the speedometer is gonna be fixed hopefully, whether it's a gear or just the cable needs a good lube. And they're servicing the differential too..opening it up and inspecting to see whether the gears really are 3.73, if they're not they MIGHT throw a 3.73 set in, and they're gonna fill it back up with brand new fluid, and friction modifier. So...knocking a bunch of birds out with one stone. I wanna get this car running cherry, because so far, I'm in love with it. I don't need any surprises! __________________ '91 Mustang GT 5.0 AOD Daily Driver Current stats: NEW 302 short block, E-303 cam (@.050, 220/220, .498/.498, 110 degrees), 1.6 roller rockers, Performer RPM heads (aluminum, 1.9/1.6, 60cc chambers), Cobra intake, Granatelli 75mm MAF, Billet AFPR, Equal-Length Shorty Headers, Off-Road X Pipe, Flowmasters, 4.10 POSI 13.73 at 103.8, ~2.2 60'

01-20-2003, 01:32 PM	#3
cyberstang5.0 347ci of HORSE POWER!!! Join Date: Jul 2001 Location: Houston, TX Posts: 1,416	The tranny will shift only at a certin pressure inside the valve body. It does not use the speedo to determine the shift points. The tranny does have a gear inside of it to turn the speedo cable which moves the speedometer. That might be the way the older trannys were built (not sure on that one) but that is not how the newer ones are run.