Auto to Manual Swap

[89Legendary]

For those who have a 5 speed conversion...Does the AT ECU work with the MT? I've been driving mine with the AT ECU for a while and swap out with a MT and there no differences...How about the TCU under the seat?

[ochn77]

Originally Posted by 18 characters long

That said, the AT axle can be used in the MT I-shaft, but not the other way 'round.

is this true?

the other day dawson said you needed the axle. it threw me off when thinking about the manual swap because the car i got all the parts off of is crushed, but i never got the MT outter axle.... i just got the MT intermidiate shaft.

that's all i need right? the outter axles still work with the manual trans?

[18 characters long]

Yes that's all you need is the intermediate shaft. I don't know why, they look exactly the same, but you can ask Tony, they will not interchange. But the automatic axle will fit into the manual intermediate shaft. I have both of my automatic axles still in my car because it has ABS and my parts car didn't. I also broke a passenger side axle and got a junk yard replacement from a '90 LS automatic.

[ochn77]

preciate it dawson, i was seriously starting to think i was screwed.

[telafonic]

Originally Posted by 18 characters long

I don't know why, they look exactly the same, but you can ask Tony, they will not interchange.

The diameter of the part going into the transmission is slightly larger on the automatic intermediate shafts.

[ochn77]

i'd take pics of both but i put on the intermiediate for the manual today and i'm not taking any parts off with my time schedule for this build. i have the auto half shaft still though.

looking at them... they are extremely similar though. it's gotta be very minute changes. i looked at them side by side one time and they were millimeters apart.

which is just retarded.

[l4zy415]

I'll get pics of it tomorrow. I have both of them sitting on the shelves.

[ochn77]

well fellas... i had the MT halfshaft in place, fit the trans. unfortunately the automatic passenger side axle doesn't insert into it.

the manual halfshaft has splines that run the entire length of the female hole on the bearing side; the automatic half shaft does not.


the automatic halfshaft and the automatic passenger side axle have half length splines. the a/t h/s female hole has only splines on the inner half of the hole, while having a smooth bore at the outer half of the hole. the same on the axle male shaft; splines on the outer half of the axle shaft, and smooth cylinder on the inner half of the male axle shaft.


here's the difference in the two halfshafts.
the automatic shaft will fit into the manual trans, but the mount flange on the a/t h/s is further from the bearing. so it gets into the manual trans but the mount flange won't fit right onto the engine block. meanwhile the m/t h/s fits perfect. tomorrow i'm going to a driveshaft shop to see if they can switch the bearings *that have the mount flange attached* from one to the other.

now, i have no idea if the difference in Dawson's build was because it was an earlier model, but that's what happened today.

i had the m/t halfshaft in place and bolted, and the a/t pass. axle would not insert into it because the m/t halfshaft had full female splines, while the a/t pass. axle had only half male splines at the end and the other half was smooth shaft.



still very much appreciate you Dawson for helping me remember which positive and negative cables were by the underhood fuse box.

[sam o nela]

Originally Posted by 89HondaLegend

^ Hmmm I wonder if that has something to do in between years?
When I put a manual transmission into my previously automatic turbo Legend I DID replace the intermediate shaft however I could see no difference between the two shafts. (The mounting bracket? is slightly different) Is it actually a different length?

Originally Posted by BDAZZG1

To correct this statement...
The shaft and bearing theirselves are the same, it is the bearing carrier that mounts to the engine block that is different. The Manual one sits closer to the engine by approx .250" I made this determination with both units in hand to compare. The bolt pattern is the same or it would not bolt to the block! Also the letters AT or MT can be found cast into the bearing carrier.

.....

[ochn77]

yeah, exactly. the half shaft fits to the trans, but you're leaving off the female end.

on the m/t halfshaft you got full splines on the inside. on the a/t halfshaft you got half splines.

one the m/t halfshaft the bearing carrier *the mount flange* is shorter than the a/t halfshaft.
...so you can fit the a/t halfshaft into the m/t trans with the bearing carrier tilted, but it won't bolt to the motor block.

....but... the a/t passenger side axle doesn't insert into the manual trans halfshaft because the a/t axle is half splined, while the m/t halfshaft is full splined.


....so... i'm going to try to go to Driveshaft King tomorrow to see if i can have the bearing carrier switched. otherwise, i'm completely screwed unless... a: i can plane the a/t halfshaft, or b: somehow get one of yall to ship me a manual pass. side axle.