Looking at an 87 IROC - Bad t5 Transmission?
Thread Starter
Junior Member

Joined: Mar 2009
Posts: 80
Likes: 15
From: Iowa
Car: 1984 Chevy Camaro & 1988 Trans Am
Engine: H/C/I LS1 & 305 LB9
Transmission: T56 Magnum-F 2.66 & Stock T5
Axle/Gears: QP 9" TruTrac 3.70 & Stock 10bolt
Looking at an 87 IROC - Bad t5 Transmission?
Pretty sure I already know the answer is yes that it's bad, however I'm unfamiliar with these transmissions and just want to be sure I'm going into the deal right. I already have another T5 sourced.
The car is a 1987 Iroc-Z 305tpi.
Car itself is gorgeous and the motor runs great.
However at idle, there is a constant 'clicking' noise. If you push in the clutch, the noise goes away.
It goes into and out of all gears fine.
All gears sound normal except 3rd. As soon as you hit third its just a ton of very loud knocking/tapping noise which goes away as soon as you get out of third. It still drives fine in third and goes in and out of third fine.
Either way I'm probably going to buy the car if he works with me on price a bit.
Just wanting to maybe know specifics on what it could be in the trans assuming that's the problem.
The car is a 1987 Iroc-Z 305tpi.
Car itself is gorgeous and the motor runs great.
However at idle, there is a constant 'clicking' noise. If you push in the clutch, the noise goes away.
It goes into and out of all gears fine.
All gears sound normal except 3rd. As soon as you hit third its just a ton of very loud knocking/tapping noise which goes away as soon as you get out of third. It still drives fine in third and goes in and out of third fine.
Either way I'm probably going to buy the car if he works with me on price a bit.
Just wanting to maybe know specifics on what it could be in the trans assuming that's the problem.
Member
iTrader: (1)
Joined: Mar 2011
Posts: 221
Likes: 0
From: Starkville
Car: 88 Trans Am
Engine: 350
Transmission: T5
Axle/Gears: Posi
Re: Looking at an 87 IROC - Bad t5 Transmission?
i got my rebuilt WC t5 from Man-Trans $600 plus 200 shipping. delivery to your door. if you want their information let me know
Joined: Dec 2001
Posts: 9,937
Likes: 636
From: Chicagoland
Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
Transmission: World Class T-5
Axle/Gears: BW 3.45
Re: Looking at an 87 IROC - Bad t5 Transmission?
Pretty sure I already know the answer is yes that it's bad, however I'm unfamiliar with these transmissions and just want to be sure I'm going into the deal right. I already have another T5 sourced.
The car is a 1987 Iroc-Z 305tpi.
Car itself is gorgeous and the motor runs great.
However at idle, there is a constant 'clicking' noise. If you push in the clutch, the noise goes away.
It goes into and out of all gears fine.
All gears sound normal except 3rd. As soon as you hit third its just a ton of very loud knocking/tapping noise which goes away as soon as you get out of third. It still drives fine in third and goes in and out of third fine.
Either way I'm probably going to buy the car if he works with me on price a bit.
Just wanting to maybe know specifics on what it could be in the trans assuming that's the problem.
The car is a 1987 Iroc-Z 305tpi.
Car itself is gorgeous and the motor runs great.
However at idle, there is a constant 'clicking' noise. If you push in the clutch, the noise goes away.
It goes into and out of all gears fine.
All gears sound normal except 3rd. As soon as you hit third its just a ton of very loud knocking/tapping noise which goes away as soon as you get out of third. It still drives fine in third and goes in and out of third fine.
Either way I'm probably going to buy the car if he works with me on price a bit.
Just wanting to maybe know specifics on what it could be in the trans assuming that's the problem.
Thread Starter
Junior Member

Joined: Mar 2009
Posts: 80
Likes: 15
From: Iowa
Car: 1984 Chevy Camaro & 1988 Trans Am
Engine: H/C/I LS1 & 305 LB9
Transmission: T56 Magnum-F 2.66 & Stock T5
Axle/Gears: QP 9" TruTrac 3.70 & Stock 10bolt
Re: Looking at an 87 IROC - Bad t5 Transmission?
it's black, heres a pic

Anyway i actually already have a t5 sourced, its used but its from a friend's brother who went auto. Hopefully I'll get it for just like $100.
Going to try to pick up the car tonight for the 1500-1700 area

Anyway i actually already have a t5 sourced, its used but its from a friend's brother who went auto. Hopefully I'll get it for just like $100.
Going to try to pick up the car tonight for the 1500-1700 area
Joined: Dec 2005
Posts: 6,499
Likes: 31
From: Macon, GA
Car: 1992 Camaro RS
Engine: Vortec headed 355, xe262
Transmission: T56
Axle/Gears: 9-bolt 3.70
Re: Looking at an 87 IROC - Bad t5 Transmission?
My T56 makes a horrendous racket in neutral sometimes.... Has run fine for years with a 350 in front of it making a good amount of torque.
Thread Starter
Junior Member

Joined: Mar 2009
Posts: 80
Likes: 15
From: Iowa
Car: 1984 Chevy Camaro & 1988 Trans Am
Engine: H/C/I LS1 & 305 LB9
Transmission: T56 Magnum-F 2.66 & Stock T5
Axle/Gears: QP 9" TruTrac 3.70 & Stock 10bolt
Re: Looking at an 87 IROC - Bad t5 Transmission?
yeah my first 99 z28 t56 made a lot of noise in neutral and while cruising in 6th, i think its trans mount was bad though and it was just vibrations.
my 99 formula was quiet until I put the cam in it, it made the shifter rattle pretty bad heh.
my 99 formula was quiet until I put the cam in it, it made the shifter rattle pretty bad heh.
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Member
Joined: Feb 2009
Posts: 186
Likes: 3
From: Independence, Kansas
Car: 1987 IROC-Z Convertable
Engine: 305 TPI
Transmission: 5 Speed BW T-5
Axle/Gears: 3.08 Posi
Re: Looking at an 87 IROC - Bad t5 Transmission?
I would bet there is a tooth or teeth missing on either the 3rd gear itself or the cluster gear has a tooth or teeth missing for 3rd. My son just ripped ALL the teeth off of his, but he has 500+ Hp to do that with. Myself, I have hurt those tranny's even with my stock 305TPI motor. 3rd is the weak link in the T-5's and the case can and does flex if your running any kind of power at all to them. My son just finished, with my help, the TK0600RR conversion and likes it real well so far - it's still in the breakin period tho so I don't know how the shifts will be at 6800. My two cents, hope you can pick that one up for 100.00, thats a good deal if its good.
Joined: Jul 1999
Posts: 12,088
Likes: 125
From: SALEM, NH
Car: '88 Formula
Engine: LC9
Transmission: 4L60E
Axle/Gears: 3.89 9"
Re: Looking at an 87 IROC - Bad t5 Transmission?
I would bet there is a tooth or teeth missing on either the 3rd gear itself or the cluster gear has a tooth or teeth missing for 3rd. My son just ripped ALL the teeth off of his, but he has 500+ Hp to do that with. Myself, I have hurt those tranny's even with my stock 305TPI motor. 3rd is the weak link in the T-5's and the case can and does flex if your running any kind of power at all to them. My son just finished, with my help, the TK0600RR conversion and likes it real well so far - it's still in the breakin period tho so I don't know how the shifts will be at 6800. My two cents, hope you can pick that one up for 100.00, thats a good deal if its good.
-- Joe
Member
Joined: Feb 2009
Posts: 186
Likes: 3
From: Independence, Kansas
Car: 1987 IROC-Z Convertable
Engine: 305 TPI
Transmission: 5 Speed BW T-5
Axle/Gears: 3.08 Posi
Re: Looking at an 87 IROC - Bad t5 Transmission?
Or if you hit it at 7000 with 510HP - bad things happen!
Joined: Jul 1999
Posts: 12,088
Likes: 125
From: SALEM, NH
Car: '88 Formula
Engine: LC9
Transmission: 4L60E
Axle/Gears: 3.89 9"
Member
Joined: Feb 2009
Posts: 186
Likes: 3
From: Independence, Kansas
Car: 1987 IROC-Z Convertable
Engine: 305 TPI
Transmission: 5 Speed BW T-5
Axle/Gears: 3.08 Posi
Re: Looking at an 87 IROC - Bad t5 Transmission?
Ya know, it really is about the torque that we are putting into these cheap little boxes. Horsepower really doesn't break them, but torque is very hard on them. We are at about 485 ft/lbs on a 300 rated trans, so even at 6200, sometime, somewhere, when you least expect it ............. and we knew that when I was putting it all together for my son. That "cheap little box" held up for about 8 months. All was good in the beginning, then the bearings started to "talk" a little, then a little more, then after I retimed the motor because my son said it wasn't running quite right after a cam replacement (same cam) he went from 2nd at 7000 to BOOM just as soon as it went into what used to be 3rd. We went with a TKO600RR just in the last couple of weeks and it is working very good right now, but we are still in the break-in miles, so I won't say too much until we can bang that thing like a screen door at 7000. I will let ya know how that goes.
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