Trasmission clunks HARD into reverse ---

[alwayscode390]

Hey Guys---

The car has poly engine mounts, so I am not sure if that has something to do with the engine not giving the tranny the "move" it needs.

When I go from park to REVERSE it seems to take a second to engage, then CLUNK. The other gears are smoother, but still seem to be slow to react.

Does this sound like a u-joint, or tranny problems? ---

 

[Jan Larsson]

Welcome to the club ... mine is the same ... and the engine takes a big jump when I put it in revers as per my other thread on the forum.

 

[alwayscode390]

I know you have a fresh rebuilt engine, but is your tranny rebuilt too?

What type of mounts are you running? Do you have fresh u-joints?

I will ask a buddy of mine to watch the engine , I cant tell if it is jumping like yours. Thanks for the reply ---

 

[1KWIKSIX]

Clunk in rear end

Have a reputable tranny shop check the backlash of your ring gear my friend.

I didn't bother having mine checked, just thought the big clunk was normal.

Ended up with a broken tooth off the ring gear.
Needless to say a new ring and pinion gear set was req'd. Just for ****s and gigles, had him check back lash of the existing gear before it was removed.....turned out it was twice the tolerance that it should have been. We found 0.010" to 0.016". I'm sure this contributed to my rear ends demise.

My advise is to spend a couple of bucks and have them check yours.....wish I did.


Good Luck!


dave

 

[Jan Larsson]

I know you have a fresh rebuilt engine, but is your tranny rebuilt too?

What type of mounts are you running? Do you have fresh u-joints?

I will ask a buddy of mine to watch the engine , I cant tell if it is jumping like yours. Thanks for the reply ---

All new stock mounts (after market both for engine and tranny) ... u-joints are new as well.

Tranny was rebuilt many miles ago, once when I owned it and once when prevoius owner had it. Always had a very loud/hard clunk putting it in reverse.

 

[alwayscode390]

Have a reputable tranny shop check the backlash of your ring gear my friend.

I didn't bother having mine checked, just thought the big clunk was normal.

Ended up with a broken tooth off the ring gear.
Needless to say a new ring and pinion gear set was req'd. Just for ****s and gigles, had him check back lash of the existing gear before it was removed.....turned out it was twice the tolerance that it should have been. We found 0.010" to 0.016". I'm sure this contributed to my rear ends demise.

My advise is to spend a couple of bucks and have them check yours.....wish I did.


Good Luck!


dave

Great advice. This car has been running drag radials for awhile, I bet the rear end is tired by now. If I end up swapping a new set in, do most people just go back with the 3.27's or is there another recommended ratio?

I know the NA guys like 4.10's ... but usually thats too high for a turbo'd vehicle right?

I dont know if the fact I run the edelbrock cam would be a factor in my choice, or when I upgrade my torque converter?

THANKS ---

 

[Razor]

Parts are tough to get and expensive for the 9 bolt. Most upgrade to the 9inch, 12 bolt or Dana.

The posi is what typically goes out first.. the gears tweak and the rear end howls at 45-50 MPH.. bearings are $$$$.

The GN rear is different that the TTA rear.

 

[alwayscode390]

Parts are tough to get and expensive for the 9 bolt. Most upgrade to the 9inch, 12 bolt or Dana.

The posi is what typically goes out first.. the gears tweak and the rear end howls at 45-50 MPH.. bearings are $$$$.

The GN rear is different that the TTA rear.

Could a dying posi unit make the clunk I am talking about when I shift?

My rear end is definately starting to howl, I wasnt sure if it was the drag radials making noise or not ---

 

[Razor]

Could a dying posi unit make the clunk I am talking about when I shift?

My rear end is definately starting to howl, I wasnt sure if it was the drag radials making noise or not ---

You need to get the car on a lift or be near parts to see where the noise is coming from. Something that over the net cant be done.

Take the cover off and inspect, look for metal, etc. get back to basics troubleshooting it.

 

[dvernst]

Could be the axle shafts clunking in the carrier.

 

[89ICBM]

Hey Guys---

The car has poly engine mounts, so I am not sure if that has something to do with the engine not giving the tranny the "move" it needs.

When I go from park to REVERSE it seems to take a second to engage, then CLUNK. The other gears are smoother, but still seem to be slow to react.

Does this sound like a u-joint, or tranny problems? ---

OK! I don't know how many miles are on your car but, I can tell you that the problem you describe is common. Just let the motor warm up a bit before putting it into reverse, let the idle stabilize down to 650 or 700 and see if that helps. The car starts in open loop so your idle could be at 1k or more when you drop it into reverse, not good for the gears.
They are ring & pinion so there is calculated back lash which means that the travel between the teeth of the two gears can cause a cluncking noise when the pinion comes off of compression of forward to engage into reverse. This noise is amplified by the bell that surrounds it called a housing.
To be prudent, have the rear end lube changed and don't forget the additive that goes with the lube for the limited slip clutch pack. It has been my experience that the additive wears out and the clutch pack will slip causing the slugish feeling you mentioned.
I hope this will help you!

Frank