T5 rebuild question: dog ring or synchronized gears

jerry S

New Member
Sep 3, 2003
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52.22N 5.12E
Ok. Now that I have come to my senses about porting and polishing the heads, I still have some money burning a hole in my pocket. I can get a T-5 case over here for basically nothing. It would require a complete rebuild, however. I see that G-Force Tranz offers T-5 guts that can handle up to 600 hp on the street. These are offered as synchronized, dog ring straight cut, and helical cut dog ring and all are rated up to 600 hp. Other than dog ring gears being noisier (and 70% more expensive), can somebody educate me as to the best way to go? I have 400hp right now but will be adding a shot of nitrous so I want the overkill of this 600 hp rated tranny. Also, what are the best ratios for street and occasional strip? As for OD, I am guessing that the .63 is the best way to go if I drop in 4.11s. That would give me a cruising rpm at 65 mph of 2241.
 
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Go for the standard synchro'ed helical type if they're all rated for 600hp.

Straight cut gears can be made with bigger teeth and so can be stronger, and with more simple meshing they are more efficient. They could probably be thinner for the same power rating as well, making them lighter, and thus more efficient again.

Dogs are just really basic sychros that will be noisier and rougher. The advantage of them is strength, so I guess they might be more robust if you have a habit of grinding gears in an equally rated box.
 
If you have the cash buy the best you can afford. It is a real pain it the butt swapping in another t-5 every year. im on my 6th t-5 i hate swapping them in and out. finally bought a rebuilt world class t-5. been 6 months and so far so good.
 
Actually, dog rings are not "syncros" at all. That is, they do nothing to help match the rotating speed of the gear you are shifting into. You don't want that for the street unless you are really hard core! You can't just push the clutch in and shift like a street car. You would have to "manually" match the engine RPM to the gear you are shifting into with roadracer style throttle "blips" for each downshift!
 
Yes that is what I thought as well. The synchro design is for the street and that is what I recommend. If you are doing the upgrade kit Jerry you need to get the upgraded mainshaft and small parts kit. Otherwise that will be your weak link and you will shatter that which will possibly destroy your gears too.
 
Yeah, get the synchro ones. Dog rings are for racing. like 86bluecobra I'm on my 3rd and had it rebuilt to the 330FT# specs with the 0.63 overdrive as I have 4.11s out back for now. I may be switching to 3.70s or so due to I may be over my powerband going through the traps.
 
I've destroyed a BRAND NEW T5Z from Ford Performance. in under 2000 MILES. Car is only pumping 318 RWH and 350 RWFT/IBS..... but that still is over the rating for the T5Z... So I guess too, it is time for an UPGRADE..dang this hobby is getting pricey!
 
steel1212 said:
Yeah, get the synchro ones. Dog rings are for racing. like 86bluecobra I'm on my 3rd and had it rebuilt to the 330FT# specs with the 0.63 overdrive as I have 4.11s out back for now. I may be switching to 3.70s or so due to I may be over my powerband going through the traps.

69Rcode_Mach1 said:
If you are doing the upgrade kit Jerry you need to get the upgraded mainshaft and small parts kit.

have a look at this link:

http://www.g-forcetransmissions.com/tran_gt-5.asp

it does come with an upgraded mainshaft and according to G-Force "Generally, it can be assumed that with the available upgraded mainshaft, the G-Force T-5 kit will handle roughly 600 hp or 500 ft-lb. or torque in a 3300 lb. vehicle running drag radials at the track with a moderate clutch upgrade."


and in the pricing section, it gives the following description: "True Bolt-in synchronized replacement gearsets capable of handling up to 600 streetable * horsepower Kit Prices (you build it using your transmission) 1st to 4th gear sets, includes 1st,2nd,3rd mainshaft gears, 26 spline input shaft with input drive gear (4th), complete cluster shaft with gears 1st, 2nd, 3rd, and cluster drive gear (4th)" for $1095. If you really want to be bulletproof, you can upgrade the mainshaft to ASTM 9310 High Nickel Steel for an additional $335 or to ASTM 4340-300M Thru Hard Premium Alloy for an additional $495.

Here is the link for that: http://www.g-forcetransmissions.com/tran_t-5_price.asp

As for the torque, I am putting down 400 ft lbs at the rear wheels behind a c6. I have to imagine that I am close to 500 at the fly, so I would go with the hard premium alloy mainshaft upgrade.

I think this could be a good way to go. Getting a TKO over here will cost a fortune. But since I can get a T5 core easy and cheap, I can have these parts brought over piece by piece to avoid the 30% in duty and VAT plus the outrageous shipping costs. (that is the price of coming to visit me and stay at my house. You have to bring parts for the mustang). I think this looks good.
 
steel1212 said:
On the dog rings my understanding is your basically just grinding them in only they are strong enough to take it.

then synchro it shall be. If the straight cut gears is what makes them stronger, I am wondering why both gear sets are rated for the same HP but the dog ring gears are 70% more expensive. If they are both equally strong but the synchros are cheaper and less noisy, why would anyone get the dog rings?
 
Dog ring gearboxes are built for racing, and are great on track. They shift faster without the syncros slowing things down. They also can be shifted without the clutch, but the technique does take time to learn. They're not good on the street because you can't "granny shift", every shift has to be a quick and positive "power" shift. They also aren't designed to last for 100,000 miles worth of shifts. The action is similar to and OLD truck that has to be double-clutched every shift. This may help www.hewland.com/svga/help.htm
It's hard to explain without using one!
steve
 
tylerrocks said:
I would be intrested to hear your combo

Tyler

-351W bored .040 over, 10.5 CR
-stock crank honed, polished, rebalanced.
-Eagle forged I beam rods (5.956 inches)
-SRP forged flat top pistons, part number 138731
-Edelbrock RPM Performer cylinder heads, part #60259 60 cc combustion
chamber, 170 cc intake runner, 60 cc exhaust runner
-comp cams pro magnum roller rockers, part # CCA-1332-16
-comp cams high tech push rods, part # CCA-7965-16
-Edelbrock RPM Air Gap intake manifold
-crower cam:

Adv. Dur. Intake: 297º, Lift: 0.538
Adv. Dur Exhaust: 308º, Lift: 0.534

Duration at .050"
Intake: 236
Exhaust: 242

-hooker comp. cermanic coated long tube headers (1 5/8" collector)
-dual exhaust (2.5")
-MSD pro-billet dizzy
-MSD 6AL ignition
-holley 650 cfm vacuum secondary carb, part #0-80783C
-C6 auto with a crappy TQ.

I am making 300 rwhp and 400 ft lbs of torque running very rich at 11.1 and only 28 degrees total timing. I am expecting more power once the engine breaks in (just a few hundred miles on it) and once I advance the timing and send the carb to Jet Performance for a stage 3 work up. I should see another 20 hp or more at the rear wheels once the engine breaks in and I get the carb and timing right.
 
Dbeck002 said:
You should see a lot more power with that once its tuned right.

I really hope you are right. I see guys with similar builds putting down 350-360 rwhp. My torque numbers are awesome but I just have to think that I have not squeezed every drop out of my car that's in there. I know that my C6 eats an inordinate amount of power. then there is the crapola torque converter in there and the fact that my track lock is close to 40 years old. I have to be losing a ton of power through the drive line given its current state. I am sure with a new true trac and either a top of the line TC or a built T5, I will see the numbers and time slips that I know are possible.
 
Wow what the heck are you guys doing to your t5's. I have had a t5z in my car for... uh over four years now and never have had a problem. Im pretty positive my last engine was making more power than it is rated for too. I never power shift though, that i know is a big no no with the t5. I even blew the crap out of my 8" with 4 people in teh car. At the time i thought teh t5 was the weekest link.
 
steve wilson said:
It's hard to explain without using one!
steve

Not really, its alot like a motorcycle transmission. Click-Bang and you're in gear. The bikes just pop into gear, though. Gotta drive a dogbox like you hate it. I saw an in-car video of a guy driving an 800hp R32 Skyline with an HKS dogbox.....and he was granny/clutch shifting it. Sounded like a rock crusher!
 
I always loved how quick i could shift my motorcycle. Never used the clutch after first. roll off the throttle "Click-Bang" and back to WOT. I think I would be afraid I was ruining the tranny if the dogbones sounded like "rock crusher" or ground into gears. Does anyone have personal exerience with the G-force dog bone combo? I would love to have a tranny that worked like my bike.
 
I had to the opportunity to drive our company racecar with a Jerico 4-speed and that had to be the most violent shifts I have ever experienced. The transmission literally pulls itself into engagement of the next gear because of the undercut of the dog rings. It shifts as fast as you can pull the shifter and without having to forcefully powershift it. :D

Should really only be used on a dedicated race car. They are very noisy, lots of clanking and banging, but way more fun than a synchro'd tranny.