new diff, wrong speed on speedo

[tomjan87]

hey everyone.

I recently(or more like 5 months ago) switched from a 4.3 diff to a 3.9. I have a 87 turbo car, and from what I understand, that is what should have been in there from the start. the speedo was correct when the 4.3 was in it. it is now off. I would like to get it back on. does anyone know how to do this without swapping in a tranny from a different car with a 3.9 in it.

I called toyota already, and they have no idea and said they couldn't fix it.
Thanks to anyone who can give me a hand.

Joe

 

[mkIIIman089]

You need to get the speedo drive gear from a car that came factory with that diff; or just order a new one from Jay Marks Toyota (here on the forums) I would imagine. I don't know exactly what it looks like or how it goes in... sry about that.

Someone must have swapped in that 4.30 diff at some point, since as you said the stock 87T should have the 3.91 in it.
http://www.mkiiitech.com/forums/viewtopic.php?t=40

 

[tomjan87]

Thanks man,

Some guy did a fair amount of work to it, he was a drug dealer actually in florida, so that may explain all the mods and wierd stuff.
Ill have to order that.

thanks agian
Joe

anyone know how to put it in??

 

[mkIIIman089]

Does anyone know the specifics with which exact drive gear is needed to have my R154 match up with the 4.30 gears? Does it need to be from an auto or a 5 spd? And do I need the housing for it as well?

 

[supraguy31]

Should be the Small gear that is on the End of the Speedo Cable. The one that goes into the Transmission itself. Change that gear out and you Should be back on track. I just went from a 4.30 Gear Ratio on my 84 Supra to a 3.73 Gear ratio and I changed the End Gear out. Solved the problem... You have to change the gear to compensate for the change in Diffs

Robert

 

[shaeff]

Does anyone know the specifics with which exact drive gear is needed to have my R154 match up with the 4.30 gears? Does it need to be from an auto or a 5 spd? And do I need the housing for it as well?

since the 4.3 is from the N/A cars, i'd assume you need the gear from a W58 (n/a 5sp tranny) it's probably the same mounting for the r154, though i dont know for sure since i dont have one. check out the pic i attached, you probably just need to pull it off and slap it on your tranny, which means you'd probably use the housing. (i've got an extra, PM me if you'd like)

Should be the Small gear that is on the End of the Speedo Cable. The one that goes into the Transmission itself. Change that gear out and you Should be back on track. I just went from a 4.30 Gear Ratio on my 84 Supra to a 3.73 Gear ratio and I changed the End Gear out. Solved the problem... You have to change the gear to compensate for the change in Diffs

when you pull off the speedo cable (on my w58) there is not a gear on it. the gear is in the tranny. you'd need to switch that gear, and on my car, it's real easy though. see below:


here, i took pics of my old w58 (RIP, haha) it looks like the speedo gear is held in with one bolt. it appears that if you pull that bolt, it should come right out. i dont know if you'll lose gear oil doing it, you probably will so have a pan ready.

-shaeff

*click to enlarge

 

[tomjan87]

Thanks guys,
I knew there was a way, but didn't know how to do it. its been a pain watching my speed so carfully lately, and cops dont seem to like sports cars. lol

oh well
thnaks again
Joe

 

[lagged]

just so you know when you undue that bolt and take that thing out gear oil will spill everywhere if you dont drain it first.

 

[shaeff]

good to know, i figured it would, but i wasnt sure because i've never taken that bolt out before.

-shaeff