86Chicken

The Question:
Is there supposed to be a a large weight hanging from the rear of a T-5 on an '86 2.8??

It appears to a counter balance or vibration damper of some sort.

The Story:
I have an unusual clutch chatter problem when starting out in first gear. I pulled the tranny down and could not find anything wrong.
The clutch looks fine, no oil, excessive wear or broken springs, basically looks new (its less than 1000 highway miles old).
All mounts have been replaced already (GM motor mounts and a ES tranny mount).

My Helm book implies that the damper is only used on 4-cyls but I got this tranny from a 6 .

Can anyone confirm this??

Any help is appreciated!!
Thanks
Dale

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1986 FireBird
2.8L MPFI
Gutted Cat, No muffler (Sweet Sound)
Was 700-R4 --> Now T5

Camaro_hunter_d

my 92 3.1 does not have any such thing on it...if that helps...

AntiVTEC

No such thing on my tranny either. But before you go and take it off, see if its anything integral to the structure of the tranny... Otherwise, if its just some piece of metal hanging by a strip of wire, take that bad boy off! payce.

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85 2.8L Sport Coupe 5-speed.
Mods: Hpertech chip and powerstat, MSD 6A-L, Crane fireball coil, Dynomax hi-flow cat and catback system with a dynomax magnum race bullet muffler on the i-pipe, K&N filterchargers, Eibach and Tokiko springs/shocks setup, Global west sub frames, Suspension techniqs front and rear sway bars, and good ole 88 IROC wheels with Kumo Ecstas on em!
"I'm out to seek those pesky VTEC boys!" (don't get me wrong, I'm asian myself! hehe)

Wins: 2000 V6 Accord, 69 302 Mustang, 2000 Auto VR6 Jetta, 89 Toyota MR2, 90 Civic Si, 76 350 Camaro.

86Chicken

Thanks for the input!! When I put it back up I think I will leave it off and see what happens.
The damper is not a structural piece, just a big (20# +/-) weight hanging off the back of the tranny.
I still have to check the runout on the flywheel yet then the tranny goes back in (again!).

I'll post the results when I am done.
Thanks
Dale

84TransAm

When i was pulling a torque arm bracket off a V6 5 speed in the junkyard it had what you described on it. I too thought it should only be for a 4 cyl, but it was a 6 cyl engine. It Does look like a damper though.

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--Steve S--
1984 Trans Am 305 LG4, 5 speed Daily Driver, Flowmaster 80 Series
Holley 600 cfm & vacuum advance
Soon: Edlebrock Intake & TES

BadBowTie

I have the same piece on my '86 2.8V6 5spd. Not sure what it does but it is there.

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'86 Camaro SC 2.8 V6, 5spd, T-Tops
Mods:

(Performance)
Flowmaster cat back exhaust

(Non-Performance)
Pioneer DEH-P4000 head unit
Pioneer 6X9 Tri-Ax speakers
Jensen 8" dual voice coil sub
Blacked out tail lights and side markers (VHT
Nightshades spray tint)

3

BadBowTie

The clutch chatter was probably because of clutch plate mis-alignment.

86Chicken

Well I got the tranny back in and left the damper off. The problem seems to be about 90+% gone but it is not enough to worry about now. I can't understand why some V6's have the damper and some do not.

I don't think that clutch mis-alignment would be a problem because once the tranny is in, the plate has no choice but to be on the input shaft.

Now all I have to fix the driveshaft imbalance and all will be well.

Thanks for all the help everyone!!
Dale

TomP

I'll try to check my '86 Firebird's GM service manual and see if it gives a reason for the "some get the weight, some don't".


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

Graeme'sFirebird

Can u describe the weight anymore? Im thinking it could be some aftermarket crap someone tried and didnt do jack. is it bolted or welded on?

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1989 Firebird
2.8 v6, t5 swapped in

Ram Hi-po clutch, Cold Air, 1.6 rockers,Lakewood LCA's, Lakewood Lift bars, Wonder Bar, 3" y-pipe, Random Tech Cat, 3" I-pipe, Flowmasters, MSd 6a, MSD Coil (Fireball in future) Accel 8.8 wires, MSD Ignition Module, Auto Meter Gauges (Water, Clock (needed one) Fuel Pressure, and 5" monster tach) 4th Gen Seats
--For Sale--
(Who says drumsets are cheap? selling my car to get a new one..) EMAIL ME!

" I'd rather run last in a full out race, than to NOT run at all ".

TomP

I checked out my manual last night, and I could not find anything about the counterweight. Pissed me off too; I remember reading about it in that book. I guess I was under the wrong sections (or maybe just too tired?)- I checked the trans section and axleshaft section.. not there... not even a picture of it.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

86Chicken

I scanned a pict from my Helm book that shows the damper ( http://www.myfirebird.com/images/damper.GIF ) so that we are all on the same page (3D-7 in the '86 Service Manual ) The damper is no. 2 in the drawings and the description says it is for the 4cyl.

With the damper off, the starting from a stop chatter/shudder is subdued but still present.

NOW I have a severe prop shaft vibration over 40mph. I noticed in the book that there are shims for the tranny mount and that they could cause the vibration and shudder (see diagnostic chart on 4A-5). When I put in my poly mount there was a shim that the directions said to put in.

My next step is to remove that shim and see it things improve.

Thanks
Dale

86Chicken

I just thought of something else. 86 2.8s are externally balanced, right? I got my flywheel out of an 84 2.8 that is also externally balanced.

I also have an engine vibration at 1700 to 2300 rpm. Could this be the problem, too?

This just keeps getting better and better

Dale

TomP

3D-7... isn't section 3 the driveshaft? Heh, whoops, missed that page... thanks! I'll go over those other pages tonight, too... this is interesting. Hey was there maybe a GM service bulletin about the clutch or vibration that said to install the damper...? I checked out alldata.com but nothing jumped out at me... stuff about clutch noise in neutral, but you've got it in gear.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

86Chicken

3D is the rear suspension.
4A is driveshaft. Close enough

I took out the shim and the car did not appear to get any better.

I think that I may have to put the damper back and see if the high-speed vibes go away but then I am stuck with low-speed shudder. I really don't want to play with the torque arm again, that thing is dangerous.

Dale


[This message has been edited by 86Chicken (edited May 30, 2001).]

fiream

what rear tranny brace are you using? is it the one from you old tranny? Because you can't use your 700-R4 tranny mount on your T5 there should be a weight or what ever at the end of the tranny, i have an 83 it not on mine.

Fiream@yahoo.com

fiream

I mean there shouldn't be a dampener

86Chicken

As an update, I took out the poly mount and replaced it with the stock one and it made no difference.

fiream- I know it is not supposed to be there in 1986 but the tranny I have is from 1984 and it came with the damper. The donor was a 2.8 (I assume this because the bellhousing matched). Basically this means that I am quite confused.

Tonite I will put the damper back on and see if the high-speed vibes go away.

Thanks for all the help so far!
Dale

BadBowTie

That is the exact same, big, ugly, nasty, counter weight that I have on my car. Now I'm going to have to find out why it's on my V6.

------------------
'86 Camaro SC 2.8 V6, 5spd, T-Tops
Mods:

(Performance)
Flowmaster cat back exhaust

(Non-Performance)
Pioneer DEH-P4000 head unit
Pioneer 6X9 Tri-Ax speakers
Jensen 8" dual voice coil sub
Blacked out tail lights and side markers (VHT
Nightshades spray tint)

3

86Chicken

Well, I put the damper back on with the stock tranny mount and most of the high speed vibes went away. I still have a moderate vibration around 40mph but I can live with it.

I then put the poly mount on and the vibes came back, not quite as bad as before though.

Tomorrow I will put the stock mount back and try my other driveshaft (the '84 is on now, the other is from the '86) to see if the vibes get better. If the vibes are still there, my next idea is to rotate my tires to see if they are all still OK. Other than that, I am all out of ideas as to the problem.

My shudder from a start problem seems to be coming back and I have no idea why! Everything looks OK.

If anyone has any ideas please post them.

Thanks for everything so far!
Dale