Tremec 3550 or t5?

jusinbailey · Dec 18, 2003

both 5 speeds have about the same gear ratios from what I have found. The new tremec is about $1400 and is rated at 525 ft/lbs, the t5 at 300 ft/lbs.

what would be the advantage of the t5? price?

RaSMG · Dec 19, 2003

the 3550's are 'stronger' than a stock t5, but the 3550 is only rated at 350 ft lbs not 525. the 3550's retail at 1400 but you can find them for cheaper here
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33733&item=2448606265
also, the t5's usually have a taller 2.97 first gear versus the steep 3.27 of the tremecs .. a new world class t5 or t5z would run just about the same as that sale price on the 3550 so the 3550 is the better deal. if you need a tranny for more power, tremec also makes the TKO which is rated ar 425 and the TKO II which is rated at 475.

66P51GT · Dec 19, 2003

3550 is not a simple bolt it from what I have read. One article suggests you have to lift the tunnel 1" to get it to fit. http://www.5speedtransmissions.com/3550_66_mustang.html

Modern Driveline confirmed it.
http://www.moderndriveline.com/Technical_Bits/classic_swaps.htm

jusinbailey · Dec 19, 2003

66P51GT said:
3550 is not a simple bolt it from what I have read. One article suggests you have to lift the tunnel 1" to get it to fit. http://www.5speedtransmissions.com/3550_66_mustang.html

Modern Driveline confirmed it.
http://www.moderndriveline.com/Technical_Bits/classic_swaps.htm

yea, i read that on the same site. whas involved in raising the tunnel?

also, what first gear ratio would you consider a better gear to use with a 400hp engine on street tires (245's). currently having 3.73 gears. what final gear ratio wouild be ideal?

66P51GT · Dec 19, 2003

At a guess...

Stripping the interior
Cutting the tunnel at the base above the tranny.
Welding a 1" spacer along the base of the tunnel.
Re-installing the interior

Not sure if the standard carpeting can be used.

ddonaca351 · Dec 19, 2003

My 3550 came with the 2.95 first gear in it. The stock (early) t5 has a 3.27, the world class or t5-z has a 2.95. The only mod I had to do when switching from the t5 to the 3550 was move the trans cross member back 1". I just cut the tack welds on the slide tube at the edges of the crossmember and slid it as far back as possible, this allowed *just* enough clearance. (then re-welded it) If you go with the 3550, it uses the t5 yoke, if you go tremec TKO it uses a c6 yoke. (just fyi)

Oh and Will runs a TKO behind his 45xhp 53xtq @ the wheels turbo cobra and it lived all season on slicks without so much as a whimper... so the ratings they use are probably a little conservative.
Dave-

3spd on floor · Dec 19, 2003

it is not NECESSARY to raise the tunnel to accomadate the 3550, 2bav8, and at least one other i know of that have put in the 3550/TKO with no tunnel mods. In my case, i couldnt afford the 3550, so i have a used (hopefully usable) T5 about to go in, and if/when i blow it up i plan to upgrade it to the Gforce gearset.

the 'early' (read 'stock 85-93 5.0L') t5's have a 3.35 first gear ratio, not 3.27 which is an optional gearset in the 3550. I dont think 3.27 came in any T5. The heavy duty T5, or T5z has the 2.95 first gear, which is a stronger gearset. The world class T5 is different than the T5z, and came in all 5spd 5.0L mustangs since 1984? I believe the world class is a roller bearing unit, and the NWC is not. i think only 4cyl cars have recieved the NWC unit since 1984 or 1985.

85-89 5.0L T5's are rated at 260 ft*lbs
90-93 5.0L T5's are rated at 305 ft*lbs

http://www.fordmuscle.com/archives/2000/09/t5swap/index2.shtml

SnakeStang65 · Dec 19, 2003

I have been saying that you need to raise the tunnel for about 2 years now. Here is a link to my site where you can see what I did to raise mine. Tremec Install It really is not hard, just takes some time.

You can install the transmission without raising the tunnel, but why go to all that work on your car and then do something so half a$$ed (official engineering term) as that. But as it has been said several times in this forum before, it is your car, do what makes you happy.

The ideal (best all around acceleration and use of torque) first gear total ratio is about 10:1. With 3.73 final and a 3.27 first that will give you around 12.2:1 which you will find that you will be in second gear before going under the stop light during normal driving. You will have a difficult time keeping your 245's from shredding under hard acceleration. But it will still be manageable. I would not recommend the 3.27 first in you car with 4.11's (13.4:1). With the 2.95 first gear that will put you at 11:1 which you find quite reasonable for daily driving and then you can still swap to 4.11's later to get a 12.1:1 final for when you want to go to the track. Honestly it is up to your own driving preferences, I have found that first gear becomes mostly useless once you cross the 13:1 mark.

Just my $0.02...

John

dolfan87 · Dec 19, 2003

Isn't it just the 65-66 cars that have clearance issues?

What year is his car?

John Z · Dec 19, 2003

SnakeStang65 said:
I have been saying that you need to raise the tunnel for about 2 years now. Here is a link to my site where you can see what I did to raise mine. Tremec Install
The ideal (best all around acceleration and use of torque) first gear total ratio is about 10:1. With 3.73 final and a 3.27 first that will give you around 12.2:1 which you will find that you will be in second gear before going under the stop light during normal driving. You will have a difficult time keeping your 245's from shredding under hard acceleration. But it will still be manageable. I would not recommend the 3.27 first in you car with 4.11's (13.4:1). With the 2.95 first gear that will put you at 11:1 which you find quite reasonable for daily driving and then you can still swap to 4.11's later to get a 12.1:1 final for when you want to go to the track. Honestly it is up to your own driving preferences, I have found that first gear becomes mostly useless once you cross the 13:1 mark.

Just my $0.02...

John

Very nice reply - it's great when posts are supported with numbers. I have noticed that my t5 with 3.55 rear gears does not take long to get up to 6000 rpm. Nice job on the of the transmission install.

302 coupe · Dec 19, 2003

I have the 3.35 1st gear T5, with a 3.70 rear, that thing is a stump puller! 2nd gear is incredible though......

302 coupe · Dec 19, 2003

ddonaca351 said:
My 3550 came with the 2.95 first gear in it. The stock (early) t5 has a 3.27, the world class or t5-z has a 2.95. The only mod I had to do when switching from the t5 to the 3550 was move the trans cross member back 1". I just cut the tack welds on the slide tube at the edges of the crossmember and slid it as far back as possible, this allowed *just* enough clearance. (then re-welded it) If you go with the 3550, it uses the t5 yoke, if you go tremec TKO it uses a c6 yoke. (just fyi)

Oh and Will runs a TKO behind his 45xhp 53xtq @ the wheels turbo cobra and it lived all season on slicks without so much as a whimper... so the ratings they use are probably a little conservative.
Dave-

I will assume you are talking about the 90LX listed in your sig and not a early model. If you are talking about a early model, what kind of crossmember are you using? Tremec's normally won't fit without modifying the tunnel because they are so much wider at the top of the case. If you don't raise the tunnel, the tranny must be angled down so much that it causes driveline angle problems.

coolblue65 · Dec 19, 2003

302 coupe said:
I will assume you are talking about the 90LX listed in your sig and not a early model. If you are talking about a early model, what kind of crossmember are you using? Tremec's normally won't fit without modifying the tunnel because they are so much wider at the top of the case. If you don't raise the tunnel, the tranny must be angled down so much that it causes driveline angle problems.

I disagree, I have made no mods to my trans tunnel and my Tremec 3550 fits fine, and I do not have any driveline angle issues. I used my stock '65 bellhousing, and installed the trans with a shortened input shaft (from Dark Horse) -instead of the widely excepted use of a spacer plate or late-model bellhousing. And I used the tubular crossmember from Dark Horse. Also was able to use my stock driveshaft.

I have a 3.50 ring and pinion, so my first gear total ratio = 11.445, and fifth gear total ratio= 2.414. I am really happy with this combo, I really like my shift timing when I shift at 6k. And with the Overdrive I can actually talk (not yell) to someone at highway speeds!

dodgestang · Dec 19, 2003

3spd on floor said:
it is not NECESSARY to raise the tunnel to accomadate the 3550, 2bav8, and at least one other i know of that have put in the 3550/TKO with no tunnel mods. In my case, i couldnt afford the 3550, so i have a used (hopefully usable) T5 about to go in, and if/when i blow it up i plan to upgrade it to the Gforce gearset.

Yes you are correct you 'can' put the 3550 without mods, but what it involves is using a tranny x member that holds the tail shaft down lower than it really should sit would puts the tranny at a slightly angle, it fits, it works, it runs, but it also becomes the powest point on your car..or so I have heard

You know....if you're gonna mod the tunnel...there's always that richmond 6 speed out there...something sexy about a mustang with a theroical top speed of a 160-180mph...off course since the mustang is about as aerodynamic as a brick, it might get a little dicey about 130

2bav8 · Dec 19, 2003

My TKO seems to fit and work just fine for the last 5+ years would out any tranny mods. However, I have managed to go through a clutch, two sets of traction bars and two set of tires.

Tremec 3550 or t5?

jusinbailey

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66P51GT

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