T5 5th gear upgrades....

So, our chumpcar has a gm 3400 v6 with a 1999 camaro v6 t5 trans behind it.

Our tire size is 23 inches. Rear is a 4.10.

Apparently, t5s don't like to shift into 5th at high rpms and high load. The 5th gear synchro assembly is brass unlike 1 through 4.

We can not get it to shift into 5th under load without horrible noises, even granny shifting.

Any ideas?

I have been googling all day and came up with nothing.

We have tried red line d4 atf and mtl to help. No difference.

We have a pro 5.0 shifter. No difference.

We verified clutch and assembly are working properly.

I could drop 2k on a Ford 8.8 Rear end and kit and buy and install 3.08 or 3.23 gears and never use 5th.

I could adapt a different trans too. I have a turbo ii trans that looks like not too much work to adapt, but will 5th gear hold up? No idea. Lots of work for nothing if it is doesn't!

What about an ax15 or ma5?

Anybody?

Tire size works well for our car and not likely to change.

T5s shift like poo but Turbo II transmissions shift even worse IMO. They don't shift at higher RPM in any gear.

If you don't want to change the ring and pinion you could try the old school drag racing "slick shift" mod where you (going from memory here) take a small bit on a die grinder and VERY CAREFULLY (this is better done with a mill and dividing head) remove every other spline from the gear and slider, and throw away the blocker ring, keys, and spring for that gear.

I am driving a T5/Ford 302 on the track these days. It's doing 4-5 shifts no problem on the front straight. The sequence is: WOT until speed hits 100-105 mph and RPMs hit 5500-6000, quick throttle lift during the shift, and back to WOT until 125 MPG at the top of the brake zone. Using Redline MTL. Running 205/50/15 and a 3.15.

What I would really like, would be a 5th gear more in the .8 range instead of the .6 I've got now.

I never had a problem with 5th in my E30 347/T5-z combo, I just quickly realized it was pointless being so overdriven. So, I dropped the rear gear way down and treated it like a 4 speed. There are more racing friendly 5th gears out there, but usually the advertised ratio is with a 2.95 first gear, so you'll have to do some math to figure out the ratio with your gear set.

I'm sure you have, but do the math so see if going to a different rear gear and staying in 4th wouldn't net you the same or more torque to the ground. For me it made sense: 3.73 rear gear necessitated using .63 5th = 2.35 final drive. 2.93 rear using 4th at 1:1 = 2.93 FD.

In reply to ross2004:

Problem is with the Mazda diff there isn't much in the way of options for taller gearing and, as Rob alluded to, options for swapping the differential aren't cheap.

BrokenYugo wrote: If you don't want to change the ring and pinion you could try the old school drag racing "slick shift" mod where you (going from memory here) take a small bit on a die grinder and VERY CAREFULLY (this is better done with a mill and dividing head) remove every other spline from the gear and slider, and throw away the blocker ring, keys, and spring for that gear.

Sounds like modding the synchros into something more like dog rings.

Okay, I realize I'm the one who started whining about the ratio.

But apologies for getting us off topic as to why the OP's won't shift.

Furious_E wrote: In reply to ross2004: Problem is with the Mazda diff there isn't much in the way of options for taller gearing and, as Rob alluded to, options for swapping the differential aren't cheap.

My mistake I kinda glazed over that part, coffee hadn't kicked in yet.

GameboyRMH wrote:

BrokenYugo wrote: If you don't want to change the ring and pinion you could try the old school drag racing "slick shift" mod where you (going from memory here) take a small bit on a die grinder and VERY CAREFULLY (this is better done with a mill and dividing head) remove every other spline from the gear and slider, and throw away the blocker ring, keys, and spring for that gear.

Sounds like modding the synchros into something more like dog rings.

That's exactly what it is, similar to the "pro shift" modification Liberty's Gears will do for you, but from before they were around.

EDIT: This PDF goes into more detail, turns out you can leave the blocker ring and whatnot in depending on how you want to go about it, or leave it in and file all the teeth off so you still have some synchro action but no more blocking.

http://www.atraonline.com/gears/2006/2006-05/2006_05_60.pdf

I have no issues shifting into 5th at high rpm on my WC T5, but then I lift off the throttle momentarily until it engages - you might want to try that.

Have you tried taking it apart and seeing what's wrong with it? That combination shouldn't be any problem for a T5 to stand up behind.

wspohn wrote: I have no issues shifting into 5th at high rpm on my WC T5, but then I lift off the throttle momentarily until it engages - you might want to try that.

Oh, we do!

We were double clutching and counting seconds and it was still notchy!

wvumtnbkr wrote:

wspohn wrote: I have no issues shifting into 5th at high rpm on my WC T5, but then I lift off the throttle momentarily until it engages - you might want to try that.

Oh, we do! We were double clutching and counting seconds and it was still notchy!

Man, I wish I knew how to rebuild these things myself. There's a good instructional DVD out there supposedly. Maybe some day.

JBasham wrote: I am driving a T5/Ford 302 on the track these days. It's doing 4-5 shifts no problem on the front straight. The sequence is: WOT until speed hits 100-105 mph and RPMs hit 5500-6000, quick throttle lift during the shift, and back to WOT until 125 MPG at the top of the brake zone. Using Redline MTL. Running 205/50/15 and a 3.15. What I would really like, would be a 5th gear more in the .8 range instead of the .6 I've got now.

I think I am missing something here. A 3.15 rear should not need to shift into 5th gear until just over 130 mph with those tires.

100 to 105 MPH is right around 4750rpm in 4th.

I would LOVE to have a 3.15 rear. This entire issue would go away!

In reply to wvumtnbkr:

Yeah my bad, I can't argue with your math. By the numbers, it should go a little past 130 before the EEC-IV cuts the fuel at what, 6250? The speeds are 5 Hz GPS and the tach is run through a pulse converter, and I'm going by video not data, so there's some slop in that rundown.

Currently high RPM cooking my oil as it is, BAD. And I'm still tracking down an ignition problem that makes the motor start missing more and more the closer I get to 5000, and after 5K it's bad enough you can start to feel it in the chassis as well as hear it in the motor.

So, many laps, somewhere around 4800 or 4900 I'm wimping out and making the shift to 5th, which is probably in the 100 mph range.

ive been watching videos all day! Thanks for the suggestion.

It seems pretty easy to rebuild one of these if you have a press.

Since I have 2 that are not working, I might as well give it a shot!

It's a Ford 302, ignition issues are a way of the world. Make sure your ignition drive isn't failing and that you aren't floating valves or dealing with a collapsing lifter (if it's hydraulic).

wvumtnbkr wrote: ive been watching videos all day! Thanks for the suggestion. It seems pretty easy to rebuild one of these if you have a press. Since I have 2 that are not working, I might as well give it a shot!

There you go! They're quite simple transmissions.

I have never had a issue with shifting into 5th gear while racing or on the street. I used to race a V8 Mustang and would shift into 5th at something like 100 mph. I was running a 3.73 rear and pushing about 275 HP to the wheels. I did have a .82 5th gear that I installed in place of the .68 ratio.

A .80 ratio 5th is available for the Mustang T5. It can be installed with out taking the trans apart, just the tail housing. I've rebuilt a half dozen of these trans and they're not hard to do if you have the right tools to work on them.

jimbbski wrote: I have never had a issue with shifting into 5th gear while racing or on the street. I used to race a V8 Mustang and would shift into 5th at something like 100 mph. I was running a 3.73 rear and pushing about 275 HP to the wheels. I did have a .82 5th gear that I installed in place of the .68 ratio. A .80 ratio 5th is available for the Mustang T5. It can be installed with out taking the trans apart, just the tail housing. I've rebuilt a half dozen of these trans and they're not hard to do if you have the right tools to work on them.

Thanks for that lead. I am so on that.

At least, as soon as I am confident that I have finally gotten my driveline angle to a safe zone. Mean time, I am finding out how to use my new tailshaft bushing puller-press this weekend, to replace the one I beat to bleeding with my first three drafts.