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T5 Issues...


wvumtnbkr
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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.

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Shot in the dark but try 80w90 gl4 gear oil mixed with Pennzoil/gm synchromesh to get your desired viscosity. I run 1:3 synchromesh and 2:3 gl4 stalube 80w90. The NV4500 for example is very sensitive to the fluid you put in it, so there may still be yet hope to get it working with yet another fluid change

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I also yanked this from a forum

--Dragging this back from the dead because I had the same problem and fixed it. I rebuilt my T5 (1990 305 model, WC) which included replacing the 5th gear brass syncro. yes there is one. Freshly rebuilt it would grind going into 5th over 2000 rpm. I discussed the problem with two transmission shops and they both told me the same thing, the cone the brass syncro ring runs against on the 5th gear needs to be "prepped" when rebuilding. It becomes highly polished over time and the syncro will no longer grab on it. One shop said to use 120 grit emery paper and the other said to use 600 grit emery paper. I took mine back apart and rubbed 320 grit emery paper across the face of the cone to remove the shine, replaced the brass syncro ring just in case, and reassembled it. Now it works great no grinding at all--

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No issues shifting to fifth at any rpm on our T5, shift as quick as you like.  Fifth synchro is bronze, all other gears are carbon fibre lined steel.  V8 WC T5 is rated at 300 ft lbs while 4 cyl non-WC is 240 ft lbs.  Running 75/90 Mobil1, no ATF mixture.  

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ours is a WC very similar to the Ford T5 WC.  It even has the same trans side bellhousing bolt pattern.

 

I suppose I could replace the blocker and synchro on the existing trans AND change rearends....

 

 

Thanks for all of the suggestions so far!

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3 minutes ago, mhr650 said:

2 words G Force…

What do they sell or make that helps shifting into 5th gear?

 

So far, Modern Driveline and Astro performance both said that the T5 does NOT like being shifted into 5th gear under heavy load. 

 

I think I am going to get a "standard rebuild" and throw a 3.27 ford 8.8 in the rear.

 

It will stop me from using 5th gear AND it will actually give me MORE tractive force at the same speed.

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34 minutes ago, Kentite said:

There is a Tremec T-5 on the clearance rack at Summit Racing right now

 

Pretty sure it is the same thing as a BW T-5. Only called a "Tremec" because of Tremec buying (or licensing?) some BW stuff. 

 

That always caused a lot of confusion back in the day trying to purchase parts for our Mustang projects. Seller would say "it's a Tremec!" - well, yea, but it's still a T-5, not a 3550 or TKO...

 

Speaking of, if you want a direct replacement, you could see if you could hunt up a "real" Tremec like a 3550 (or TKO).

 

Edit: I think all of the 3550/TKO stuff was Ford pattern only, not sure how that could hinder your adaptation

Edited by pintodave
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3550 and TKO can handle more torque.  It doesn't sound like torque is the issue here.  

 

What do do you mean by shifting into fifth under heavy load?  You also said you were granny shifting and it feels the same?

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3 hours ago, wvumtnbkr said:

Our trans is Ford pattern.

 

It is a tremec.

 

No tko or 3550 on the list in any vehicle that I can find....

 

True, 3550 did not come on anything that is actually on the Chump TCV list. But it would work  :D

 

If you don't mind a touch more weight just get a T56 and be done with it. That's on the list.

 

I've heard of this no shift into 5th problem, but never experienced it. I have experienced T5's under performance/racing conditions feeling like they are going to come apart at high speeds though. Feel like a grenade with the pin about to fall out.

 

 

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It's irs.  So, I can't just weld new brackets to the axle tubes....

 

1200 for the kit.  150 for the correct gear set.  200 to 300 for the carrier.  100 to 200 for driveshaft.  50 for bushings.

Edited by wvumtnbkr
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I'm trying to get an e or xe code rear out of an mn12 chassis (cougar /thunderbird). 

 

If I can do that, I eliminate the cost of the gears and, I *think* the driveshaft mods are easier.

 

That means I need to make my own mounts.  I did the engine and trans mounts, I think I should be able to figure this out...

 

Then all I need to do is figure out cv axles...

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I could.  I would run out of gear at about 100 mph.

 

I either need a taller rear end or a trans that doesn't mind shifting into 5th at 6000 rpm under load.

 

I think the trans, any trans, will require constant maintenance if I go the trans route.

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We use 5th gear all the time in our 3800/T5 RX-7.  The gearing works well with the 4.10 rear end and 17/225/45 tires.  Pulls all the way to redline and tops out at about 135mph.  

 

Maybe the transmission just needs a rebuild???

 

JC

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The more I hear about others not having issues, the more I think we might have 2 different dud gearboxes.

 

I am going to try to rebuild at least 1 of them in the next week or so.

 

Taller tire would not work. It would need to be about a 30" tall tire.  That would raise our ride height by over 3 inches!

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I have 1-2 and 3-2 shift issues in my mustang t5, they seem to be more related to clutch hydraulics and/or pressure plate problems than actual trans issues. This is the last of the breed semi-remote shift and concentric throw out version though, so ymmv.

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