[MrWrestlingII]

Does anybody know of anyone who’s running the Mcleod 5-Speed transmission? There’s very little online information for how long it’s been on the market. I’d be interested in swapping out my M-20 over the winter, but don’t want to take the plunge without some real world information.

Sounds like I’d need a 26 spline clutch disk, a shorter driveshaft and I may be able to use the stock cross member, moving it back one set of bolt holes on the frame.

I’ve also thought hard about the M23-Z and a 3.07 rear gear, but don’t think it’s worth the $$$ to go from my current 2.52 first gear to 2.99 in the M23. Modifying the tunnel for a TKO-600 is tempting, but I can’t bring myself to do it.

[tom s]

I have been trying to talk myself into trying one.I know there was some issues when first came out with some gasket leakage and then I heard some gear noise.I think its the same over all as your M20.I want one for my 62 GP but it would require a rear gear change as I have 2.68s with my ST-10.I will call my contact at Summit and see what their returns have been.Tom

[HO Kenny]

If you have 2 series gears I’d look for the old Richmond/ Doug nash 5 speed. 3.31:1 first gear and a 1:1 5th. It’s ratios are perfect for that kind of set up.

[MrWrestlingII]

Thanks Tom. Any information is appreciated, as I'm also trying to talk myself into one.

Mcleod's choice of first (2.99) and 5th (.63) gear ratios has me a bit perplexed. With a 3.73 rear, 5th gear is about 75mph at 2200rpm which would be perfect. But the 1st gear multiplication is 3.73x2.99= 11.15.

[Formulajones]

They are basically T-5's. The 2.99 first gear is yet another rendition of the Z spec World Class gear set. More commonly seen with the 2.95 first gear. These are just new cast cases to accept a GM bellhousing.

Astro out of Florida has been building beefed up Z-spec T-5's for years and are capable transmissions rated as high as 575 ft lbs. and 600hp with a couple of other boxes with lower ratings at less cost. Overdrive ratios are available all the way down to .60 and go up from there. Gears are a much stronger 9310 material. They sell all the parts and pieces to beef these things up.

I almost bought a McCleod to use in a GM product but the McCleod wasn't rated quite as high as I would like and was afraid it may not handle what I was going to give it in the long run. Otherwise, I wouldn't flinch at using one. The T-5 design has been around for decades and has a ton of aftermarket support. matter of fact I wouldn't be surprised if the Astro 9310 gears sets are a drop in replacement for the McCleod.

[Formulajones]

Matter of fact I just bought a brand new Z-Spec World Class T-5 with the 2.95 first gear and a .63 overdrive I'm going to run through it's paces in another car, with less power and lighter weight (3100 lbs) and see how that holds up.

It will likely get a 3.73 gear swap. I don't care for the 9.64 affective ratio with the current 3.27's.

[tom s]

my 455 in my first gen with a TKO500 is 3.27 first with a 3.31 is 10.8 with no issues.I would not worry about it at all.Tom

[Formulajones]

I'm with Tom, no worries on that deal.

[77 TRASHCAN]

What is a M-23Z? Box?

[MrWrestlingII]

Originally Posted by 77 TRASHCAN

What is a M-23Z? Box?

The m23 is Autogear’s severe duty muncie replacement. The z is a wide ratio gear set with a 2.99 first gear and 1:1 4th gear, so you can run something like a 3:07 rear gear. There are positive reports on this combo from people here.

[Formulajones]

None from me. While it satisfies some, it's still not as good as an overdrive and for the money you spend on one with the lack of benefits, it makes more sense to take the plunge to the 5 speed.

With the M23Z, you still don't have a decent effective gear ratio in first, or 2nd and 3rd for that matter, and you'll still be cruising at 26-2800 rpm just to go 70-75 mph. So there is no real gas mileage benefit, still noisy, and no wear and tear benefit.

If you're even remotely thinking about the 5 speed, I'd recommend forget about the M23, do the 5 speed and you'll never look back again and wonder why you haven't done that sooner.

[tom s]

2X FJ

[MrWrestlingII]

Originally Posted by Formulajones

None from me. While it satisfies some, it's still not as good as an overdrive and for the money you spend on one with the lack of benefits, it makes more sense to take the plunge to the 5 speed.

With the M23Z, you still don't have a decent effective gear ratio in first, or 2nd and 3rd for that matter, and you'll still be cruising at 26-2800 rpm just to go 70-75 mph. So there is no real gas mileage benefit, still noisy, and no wear and tear benefit.

If you're even remotely thinking about the 5 speed, I'd recommend forget about the M23, do the 5 speed and you'll never look back again and wonder why you haven't done that sooner.

I think the m22/23-z definitely has its place, especially if you're running a close-ratio Muncie with a big cam and say a 4.11 rear gear. All you need for the swap is the trans, new rear gear and possibly a 26 spline clutch disk. With a 3.07 rear gear, 1st gear feels the same as the original combo but now you’re running 75mph instead of 62mph at 3k, and the trans looks stock.

With an M20, it doesn’t make much sense just going from a 2.52 first gear to 2.99.

[MrWrestlingII]

Originally Posted by Formulajones

They are basically T-5's. The 2.99 first gear is yet another rendition of the Z spec World Class gear set. More commonly seen with the 2.95 first gear. These are just new cast cases to accept a GM bellhousing.

Astro out of Florida has been building beefed up Z-spec T-5's for years and are capable transmissions rated as high as 575 ft lbs. and 600hp with a couple of other boxes with lower ratings at less cost. Overdrive ratios are available all the way down to .60 and go up from there. Gears are a much stronger 9310 material. They sell all the parts and pieces to beef these things up.

I almost bought a McCleod to use in a GM product but the McCleod wasn't rated quite as high as I would like and was afraid it may not handle what I was going to give it in the long run. Otherwise, I wouldn't flinch at using one. The T-5 design has been around for decades and has a ton of aftermarket support. matter of fact I wouldn't be surprised if the Astro 9310 gears sets are a drop in replacement for the McCleod.

Formula-J.

Mcleod could really use you in their marketing dept. Seriously, you make a better pitch than the company trying to sell the product.

I have no idea why there’s so little information out there. Only 10 reviews on Summit, 2 of them poor, and nothing on You-Tube (the kids doing the Top 5 Questions video is a deterrent IMO).

[i82much]

I like muncies so I went M23Z with a 3.54 gear. I like it but no interstate, I just cruise country roads at 55 or 60. Might do gear vendors one day if i start taking road trips, but for an hour drive in the country and a few full throttle blasts in first and second I like it just how it is.

[Formulajones]

Originally Posted by MrWrestlingII

I think the m22/23-z definitely has its place, especially if you're running a close-ratio Muncie with a big cam and say a 4.11 rear gear. All you need for the swap is the trans, new rear gear and possibly a 26 spline clutch disk. With a 3.07 rear gear, 1st gear feels the same as the original combo but now you’re running 75mph instead of 62mph at 3k, and the trans looks stock.

With an M20, it doesn’t make much sense just going from a 2.52 first gear to 2.99.

If it helps, our 69 Z was an M-21 with 3.73's. I didn't like it much. I have spare stuff here so I swapped in an M-20 with 3.55's. 1-3 is actually quicker acceleration with this setup, and 4th ended up giving me another 2-300 rpm cruise speed since I could drop the rear gear at the same time.

We continued to daily drive it this way for the next 3 or so years. Knowing I wanted a 5 speed in it at some point. That day came, and I ended up going with the TKO-600 with a 2.87 first gear and .64 overdrive. I'm kicking myself for not doing it 3 years ago, lol. The 302 has no trouble pulling the car around in overdrive at any speed, and the steeper first gear was a bonus. I can cruise 70 mph at 2,000 rpm, and now it gets 21.5 mpg instead of 17 with the M-20/3.55 setup. But what a lot of people miss is how quiet cruising now is. Put this thing in 5th gear and it just goes to sleep, no more engine screaming, just goes virtually silent.

[tom s]

I talked to my friend at Summit,he said they sold a lot of them this year and had 2 returned.I might drive out to McLeod next week and see what I can learn.Tom

[Formulajones]

Originally Posted by MrWrestlingII

Formula-J.

Mcleod could really use you in their marketing dept. Seriously, you make a better pitch than the company trying to sell the product.

I have no idea why there’s so little information out there. Only 10 reviews on Summit, 2 of them poor, and nothing on You-Tube (the kids doing the Top 5 Questions video is a deterrent IMO).

LOL I'm just familiar with the T-5's thanks to being around the fox body crowd since the 80's and my son owning one.

I'm not sure why there is so little info on the McLeod either. As soon as I saw one though first thing that popped in my head is T-5. Just look at a picture of it and compare to a T-5. They are identical in design and use the same internal parts. Biggest difference is the main case being a new casting, and that's done to accept GM bellhousings. The top plate and rear tail wouldn't surprise me if they interchange as well. They make some very beefy internals for those things now. They've been around forever and when Borg Warner sold it to Tremec, they took that design and just started making more improvements, hence the 3550 boxes and TKO's all evolved from that.

I think what hurts McLeod is that TKO's have cornered that market for so long. I think the McLeod trans has the ability to be popular. I actually like the gear ratios much better than the TKO-600's. The McLeod has a much closer gear spread. If you've ever driven a T-5, especially the Z-spec with a 2.95 first gear, that's what they consider their close ratio box, very nice to drive and shift feel is better than the TKO. If you could buy one with the Astro internals, at the power they rate those T-5's for, I'd have no issue shoving one behind a stout 455.

[Formulajones]

Originally Posted by tom s

I talked to my friend at Summit,he said they sold a lot of them this year and had 2 returned.I might drive out to McLeod next week and see what I can learn.Tom

I'd love to hear about that trip Tom. More info the better. Glad to hear they sold a bunch. Maybe we'll start seeing more reviews.

Like I mentioned, I just bought a Z-spec T-5 which is basically the same thing. I didn't buy the McLeod simply because this wasn't for a retro swap.

[Formulajones]

Just to add, about the leak issue Tom mentioned.

This isn't something unheard of with these transmissions. Even the TKO's. They all use a very thin fluid that will find it's way out if not sealed up tight.

After about 600 miles of service with the new TKO I bought from American Powertrain, it started leaking.

I pulled it, ended up being the bearing retainer at the input shaft. They didn't use enough anaerobic sealant, it was very sparingly applied. I cleaned it, reinstalled with a more liberal amount of anaerobic sealant and it's been perfect for the last 2,000 miles.

The T-5 design is no different and doesn't surprise me the McLeod's had leak complaints. Not sure what McLeod is using to seal the transmissions, but the anaerobic stuff is highly recommended and works excellent. Matter of fact, if I bought one, I'd likely pull that retainer and redo it just to make sure, as well as possibly the top plate.