No reverse and very little drive - 1993 LT1
10-01-2008, 03:52 PM
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No reverse and very little drive - 1993 LT1 Hi Guys (and Girls),
I have a 1993 Trans-Am LT1 Auto and despite doing over 4000 miles with no problems since I got her 6 months ago, today it decided to let me down.
I drove about 25 miles today and then tried to reverse in a carpark. This is what is happening in each gear:
Park - Seems fine
Reverse - No drive, no movement on rear wheels (even when jacked up), when engaging reverse the wheels turn slightly forward (note, not backward) and then lock solid. The engine is engaged and won't rev over 1500 or so revs even when given full gas. As you change it back to Park very slowly you can occasionally here it clicking but no movement.
Neutrel - Provides forward motion (not full power) and if you hold it on the brake (so the wheels don't turn) there is a whinning/spinning noise. Engine revs ok but not freely.
Drive, 2 and 1 - Some power for drive but not enough to spin the wheels etc. I have not tried it on the roads to test if all the gears are working so can't tell you anymore.
I have checked the fluid level which was within the crosshatch "full" marked area when hot, in park and with the engine running. I did put some more in just incase but no difference. I assume this is the correct method to check a LT1 Autobox?
I have checked the fluid lines which appear good but I have not taken any off to check the pump. Should I?
The linkage is connected, tight and working fine.
No other visible issues from under the car.
It is a 1993 Trans-Am LT1 with just 55k miles if that helps.
I work a lot with Mustangs and miss how simple they are to work on - if ever needed. I am hoping this is a simple fix and perhaps a quick valve replacement but would love some good suggestions on where to start looking.
Many thanks,
Mick . . .
I have a 1993 Trans-Am LT1 Auto and despite doing over 4000 miles with no problems since I got her 6 months ago, today it decided to let me down.
I drove about 25 miles today and then tried to reverse in a carpark. This is what is happening in each gear:
Park - Seems fine
Reverse - No drive, no movement on rear wheels (even when jacked up), when engaging reverse the wheels turn slightly forward (note, not backward) and then lock solid. The engine is engaged and won't rev over 1500 or so revs even when given full gas. As you change it back to Park very slowly you can occasionally here it clicking but no movement.
Neutrel - Provides forward motion (not full power) and if you hold it on the brake (so the wheels don't turn) there is a whinning/spinning noise. Engine revs ok but not freely.
Drive, 2 and 1 - Some power for drive but not enough to spin the wheels etc. I have not tried it on the roads to test if all the gears are working so can't tell you anymore.
I have checked the fluid level which was within the crosshatch "full" marked area when hot, in park and with the engine running. I did put some more in just incase but no difference. I assume this is the correct method to check a LT1 Autobox?
I have checked the fluid lines which appear good but I have not taken any off to check the pump. Should I?
The linkage is connected, tight and working fine.
No other visible issues from under the car.
It is a 1993 Trans-Am LT1 with just 55k miles if that helps.
I work a lot with Mustangs and miss how simple they are to work on - if ever needed. I am hoping this is a simple fix and perhaps a quick valve replacement but would love some good suggestions on where to start looking.
Many thanks,
Mick . . .
and will need to replace or rebuild it. No easy fix on this one unfortunatley 
10-01-2008, 05:00 PM
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I have spent some time going through a manual for it and it seems to suggest the following in two seperate sections:
No Reverse: . . . Forward Clutch Not Releasing . . . or . . . Manual Valve Link Disconnected
Drive in Neutrel: Forward Clutch Not Releasing . . . or . . . Manual Valve Link Disconnected
Now, call me thick, but I see a pattern there. Does this mean that as I have both issues and these are the only two common factors between the two seperately listed faults that it muct be where my fault is?
The Clutch is logical, but what the hell is a "Manual Valve Link" and where is it?
So, I appreciate I will have to drop the tranny now, but how hard is it to resolve the above issue? What parts will I need and is it something I can do (I am basically a mechanic - mostly general restoration & engine work - but have no experience with these auto boxes) or do I need to send it to a tranny shop with a copy of the manual?
Please note, I am in the UK and therefore these boxes are not too common here.
Thanks again for your help.
Mick . . .
