[Black71gp]

I have a TH400 in my car.. not sure what it came out of but its a BOP trans. Speedo is way off.. so started to look into it. The drive gear in the case is a steel gear so it must be pressed on because i can not find the clip like in my other trans. I counted teeth and its a 21 tooth, which is way to much for my needs I have a 3.73 rear and 26.6" tire. What is the best way to remove the pressed on speedo drive gear. and when i get a new one like a 15 tooth do i need to press it on or if i get a plastic one can I use the clips or is the outputshaft different.

Any help is appreciated thanks

jarrod

[ericnova72]

It's been a while since i last looked, but I think the pressed steel gear shafts have to remain pressed and can't be converted to plastic w/clip because there is no hole for the clip to fit into in the shaft.

You can't get the required correction from the correct outer gear and housing??? There is like a 27 mph spread in just the outers.

How far off are you and in which direction??

[Black71gp]

its like 30+ miles over what it reads.. the steel gear is a 21 tooth, i have 3.73 26.6 inch tires.. the online calculators say i need a 59 tooth, which is not made...

[ericnova72]

Speedo reads 30+ mph over how fast you are actually going, or you a going 30+ mph faster than it reads??

What is the tooth count of your current outer (driven) gear??

[Black71gp]

reads 30 over what i am going driven gear is a 36 tooth I changed the trans out from my stock one a year or so ago. and been waiting till i did the rear end up grade to fix it.. and thats when i found out it was a steel gear... and the 30 or so over was with a 3.08 and 24 inch tire.. will be off a bit now i would expect with new gear and tire diameter

[ericnova72]

Crosley or Jakeshoe (members here), any help for finding the steel drive gears?

You could get most of it by going to a 45 tooth outer gear and matching housing(there are two for the TH-400, straight-thru and offset) and one of the add-on reduction boxes like 3/4, 1 ton, and heavy trucks used. Just an idea if you can't find a gear.

[jakeshoe]

I have new 15 tooth drive gears (steel).
I should have everything to get the speedo correct. I would have to check my driven gears and what you have.

You'll need the 15 tooth drive gear though.

Easiest way to get it off is to cut it with a cut off wheel almost through, hit it with a chisel to split it, and slide it off.
There is a special puller to remove them, you could make something similar with a bearing splitter and some long all-thread but I would cut that one off. It's worthless

[Black71gp]

ya cutting it off would be easy.. kinda like how i did the axle bearings and retainers.. but how hard are they to press back on the shaft with the trans in the car still????

[jakeshoe]

I use a piece of pipe that fits over the output shaft to "press" the gear back on with my favorite tool

[jakeshoe]

You need a 15 tooth drive/42 tooth driven, and the matching sleeve for the driven (40-45 tooth sleeve).

[Black71gp]

ok thank you. any locations where i can purchase those three things?

[jakeshoe]

Email me:
jakeshoe@yahoo.com

You can get it all new at GM but it ain't cheap for the sleeve.

[Black71gp]

thanks.. sent email