spock345
Well-known member
- Joined
- Nov 3, 2016
- Location
- Livermore, CA
This post is mostly going to be my musings on modern five speeds in pre 1975 cars. So I will be rambling a bit. Given the rarity of M41 gearboxes (I am now seeing prices of $2500 in some places for a rebuilt unit) I've been trying to think of a way to get a T5 into a push rod car with minimal effort. So I'd like to minimize cutting, welding, and custom fabrication. I think I have figured out a formula that would make it work. That said it'll probably be more pricey than they old T5 out of a fox body approach.
My car was originally an automatic, so it already has a wide transmission tunnel. So no need for a new tunnel there. The annoying bit is the shifter. I'd like to retain stock-ish shifter placement. A few inches back would be fine. This would mean a T5 out of a truck (S10s come to mind). So a bit of hammering and a new hole, and some shopping for the right shift lever, no problem. Then we come to the driveshaft.
One tricky bit I've been trying to figure out is the drive shaft. Most T5s have a slip yoke and I know that driveshaft shops don't like putting two slip yokes on the front driveshaft half. Also I'd like to keep the stock setup and not navigate trying to get a one piece through that weird hole in the body. Although the infinite variation of the T5 has delivered a solution in the gearbox from an S197 4.0L mustang which has a flange to bolt up to. I have noticed the gear ratios aren't the best, 3.75:1 1st and a 0.73:1 OD. So seems like if you were to somehow bolt a D type overdrive up to an M46. The S197 T5 weighs 75lbs dry versus an M41 at 90lbs. So you save some weight.
I guess that just leaves getting the gearing and input shaft right, which as I understand it isn't too hard with these gearboxes if you have cash to throw at it.
So I guess what I am envisioning is the following.
Sorry for the rant, this has been rattling through my head and I wanted to share and see what other folks think of the idea. Definitely not the cheapest way to go.
My car was originally an automatic, so it already has a wide transmission tunnel. So no need for a new tunnel there. The annoying bit is the shifter. I'd like to retain stock-ish shifter placement. A few inches back would be fine. This would mean a T5 out of a truck (S10s come to mind). So a bit of hammering and a new hole, and some shopping for the right shift lever, no problem. Then we come to the driveshaft.
One tricky bit I've been trying to figure out is the drive shaft. Most T5s have a slip yoke and I know that driveshaft shops don't like putting two slip yokes on the front driveshaft half. Also I'd like to keep the stock setup and not navigate trying to get a one piece through that weird hole in the body. Although the infinite variation of the T5 has delivered a solution in the gearbox from an S197 4.0L mustang which has a flange to bolt up to. I have noticed the gear ratios aren't the best, 3.75:1 1st and a 0.73:1 OD. So seems like if you were to somehow bolt a D type overdrive up to an M46. The S197 T5 weighs 75lbs dry versus an M41 at 90lbs. So you save some weight.
I guess that just leaves getting the gearing and input shaft right, which as I understand it isn't too hard with these gearboxes if you have cash to throw at it.
So I guess what I am envisioning is the following.
- Starting with a 140 or Amazon with either the wider tunnel or do some cutting, hammering, or welding.
- Move the shifter hole a few inches back (nothing I've found is quite far forward enough to match the M40/41 except for a TKO).
- Modify the S197 T5 with the right input shaft for a red block per documented swaps.
- Figure out the transmission cross member (again decently well documented for BW35->M40 swaps in Amazons).
- Shorten an M40 front driveshaft half and attach the right flange for the T5.
Sorry for the rant, this has been rattling through my head and I wanted to share and see what other folks think of the idea. Definitely not the cheapest way to go.