904 dragging in reverse

[MichiganRay]

Was driving the other day. Backed out of my garage no problem. Drove 30 miles pulled into a parking spot. When it came time to leave had to give the motor a bunch more RPM to back out. Dropped my driveshaft from the rear-end. In neutral, It turned freely in one direction. The Forward direction. There was a bunch of resistance tuning in the reverse direction. Is this a broken band or maybe a return spring broken not letting Forward band back off all the way. No noise when doing it. Have not pulled the pan to look yet.

 

[KickDown]

It is normal for the trans output shaft to turn easily in the forward direction. When you turn in reverse you are turning against the Sprag in the rear of the case which makes it harder to turn. If you need to give it a bunch more gas to move in reverse, then I think you may have issues with either the rear (Low/Reverse) Band or the Front (High/Reverse) Clutch.

 

[Tooljunkie]

Or brakes hanging up

 

[leechris81]

Was driving the other day. Backed out of my garage no problem. Drove 30 miles pulled into a parking spot. When it came time to leave had to give the motor a bunch more RPM to back out. Dropped my driveshaft from the rear-end. In neutral, It turned freely in one direction. The Forward direction. There was a bunch of resistance tuning in the reverse direction. Is this a broken band or maybe a return spring broken not letting Forward band back off all the way. No noise when doing it. Have not pulled the pan to look yet.

Have you checked fluid level? Low fluid condition will cause you to have to give more throttle in order to move in reverse before forward gears. Mine does this after I let it sit for a couple weeks and it bleeds in the floor. I say I’m gonna fix it every winter.

 

[Dana67Dart]

I have heard many 904s do not go into reverse rapidly after sitting for a few days maybe even over night. (My 67 does this)

I can either give it more gas to back out of the garage or put it into neutral for 10 to 30 seconds and then into reverse.

I would expect it to do that on first start but not for subsiquant restarts.

Now if you were low on fluid and parked on a slight slope you might be sucking some air on restart

 

[Ricks70Duster340]

I have heard many 904s do not go into reverse rapidly after sitting for a few days maybe even over night. (My 67 does this)

I can either give it more gas to back out of the garage or put it into neutral for 10 to 30 seconds and then into reverse.

I would expect it to do that on first start but not for subsiquant restarts.

Now if you were low on fluid and parked on a slight slope you might be sucking some air on restart

My 727 leaks down if not driven for several days. When I start the engine, I hear the pump whine until the fluid pressure builds back up. I just let it run until the whine goes away, then put it into reverse. I've had other 727's that did the same thing without the pump whine. My trans will be rebuilt soon, but once it has pressure, it is fine until it sits again for awhile.

 

[MichiganRay]

I dropped the pan & readjusted the rear band. 72 in, lbs 4 turns out. It is working fine now. It dose have an A&A Automotive reverse valve body in it and feels like it is not shifting/grabing as hard, but I have not driven it very hard yet. It was over filled with trans fluid to. The fluid was not burnt & only has a couple thousand miles on it. It was new last summer. I let it settle in a clean pan por it into a large pouring can. When I put it back in the car I strain it through a paint filter. I keep them handy to refill/reuse antifreeze also.
Wish transmission fluid was easier to see on the dip stick. Even with the red die in it to is still a guessing game. I just lay it on a clean white towel to read it.

 

[MichiganRay]

Took it for a little 200 mile run from Lansing MI to Saugatuck MI all two lane. It ran great. Shifted fine. It was just over 90° outside. The transmission ran hot went up to 210°. But there were curves, hills and several stop signs. Every time it dropped below 200° I hit a stop. Tried to cruise at 65 mph but hit 85 a few times. That was 100 miles going. The last 10 mile got in traffic and could only do 55. It cooled down to 175° and only went to 200 for a short time the rest of the trip. Driving home I did 60 mph most of the time used a gallon less of gas. 3.91 gear with a Gear Vendor unit. 3200 stall converter. Going to slap the 3.55 back in this week.
Thanks for the tips. They all pointed out something to look at.