i keep burning 2nd

[forkspear]

2004r billet forward drum, CK recalibration kit, bigger 200 servo, dual fed. Its behind a mild small block chevy 400. The transmission worked great after I rebuilt it earlier last year. Up until I overheated the tranny to the point it was puking out oil on the freeway. On a forced downshift to 2nd the band burned instantly. I changed the band and the same thing happened the same night I got it back together. On the last build I avoided a high load downshift to 2nd. This time it burned on an 3-2 upshift(im guessing) on a WOT run. It went through all the gears fine but next time I started from a stop there was no 2nd. Right now I have a line pressure gauge hooked up before I pull it this time. The pressures are not right.

Reverse 150 190-210 fluctuating
Neutral 100 185
Manual Lo 210 210
D4 120 180

Anyone have any input to steer me in the right direction to fix this?

 

[quickt]

2004r billet forward drum, CK recalibration kit, bigger 200 servo, dual fed. Its behind a mild small block chevy 400. The transmission worked great after I rebuilt it earlier last year. Up until I overheated the tranny to the point it was puking out oil on the freeway. On a forced downshift to 2nd the band burned instantly. I changed the band and the same thing happened the same night I got it back together. On the last build I avoided a high load downshift to 2nd. This time it burned on an 3-2 upshift(im guessing) on a WOT run. It went through all the gears fine but next time I started from a stop there was no 2nd. Right now I have a line pressure gauge hooked up before I pull it this time. The pressures are not right.

Reverse 150 190-210 fluctuating
Neutral 100 185
Manual Lo 210 210
D4 120 180

Anyone have any input to steer me in the right direction to fix this?

I think you line is low should be 250 plus. V-8 car I would do constant pressure and problems will be over. Could be as simple as line rise.

 

[chris718]

Even though the band is cooked put the car in l2 and take off at wot.See if the pressure drops when the shift valve opens even though its not shifting by applying the band.See/note pressure drop and post.I can walk you through it if you need help.

 

[77 cruiser]

How did the direct drum look after the first band?

 

[forkspear]

I think you line is low should be 250 plus. V-8 car I would do constant pressure and problems will be over. Could be as simple as line rise.

How do you do that? Shifts at light load would be harsh right?

Even though the band is cooked put the car in l2 and take off at wot.See if the pressure drops when the shift valve opens even though its not shifting by applying the band.See/note pressure drop and post.I can walk you through it if you need help.

I'll do that as soon as I can get it out of the corner of the shop.

How did the direct drum look after the first band?

The drum was not too bad. There was a small spot on the band that wore through to the steel and scratched it. I turned it on a brake lathe. I bought the drum rebuilt. So it was probably the second time it was turned... Do you think the drum might have something to do with the recent burning? I was planning on buying another rebuilt or turning a used drum.

Has anyone used a band other than the Alto wide red band?

 

[Otto J]

Since you turned your drum did you do anything to lengthen the pin to adjust the band correctly?

 

[bison]

The drum was not too bad. There was a small spot on the band that wore through to the steel and scratched it. I turned it on a brake lathe. I bought the drum rebuilt. So it was probably the second time it was turned... Do you think the drum might have something to do with the recent burning? I was planning on buying another rebuilt or turning a used drum.

Has anyone used a band other than the Alto wide red band?

How did you hold the drum and locate it? Did you check for runout? Did you verify no taper? How much did you cut off? What was the final OD? I dont see how it could be turned accurately in a brake lathe. Ive had to turn many drums that were thought to be ok/ looked ok since the supply of good uncut drums is disappearing. Many are previously turned and tapered and or have run out. Stock is very close to 6.180. I wouldnt use a drum under 6.160 and id want it over 6.170 for a high hp application. There is only one good way to turn one of these that i have found. A carbide cutter wont work either. Hydramatic ground them originally.

 

[quickt]

How do you do that? Shifts at light load would be harsh right?

Yes but line rise problems go away.

 

[quickt]

.

Has anyone used a band other than the Alto wide red band?

Yes I dont use the alto band anymore. If you cut the drum in a lathe you should use a ceramic cutter and it should be done on a fixture not by grabbing the Od or ID of drum. Best for the drum to be center ground. No smaller than 6.160 or 6.150 in an extreme pinch on a stocker. Or use a good used drum with a standard width Carbon band with as much carbon as you can get. Carbonite is not carbon it a Carbon Kevlar mix with very little carbon and is junk. You will be surprised how well the standard width works. I personally think its better than wide unless you have a fresh ground drum in a perfect world. As Otto stated if drum is cut you will need to mod the pin to add length.

 

[quickt]

I dont see how it could be turned accurately in a brake lathe.

agreed

 

[Otto J]

What are you running for boost valves in the pump?
If its not a BRF trans they could be really small

 

[forkspear]

How did you hold the drum and locate it?

With cones in the bushing bores

Did you check for runout? Did you verify no taper?

No I did not. I watched both go away as it turned.....

How much did you cut off?

I do not remember as it was over 6 months ago. Probably too much. I want to say .030. I could be way off.

What was the final OD?

Never checked. The only manual I have is CKs. I may be wrong but I do not remember a spec listed for OD

I dont see how it could be turned accurately in a brake lathe.

How much more accurate can you get other than centering off the bushings the drum is going to ride on in the transmission?

Ive had to turn many drums that were thought to be ok/ looked ok since the supply of good uncut drums is disappearing. Many are previously turned and tapered and or have run out. Stock is very close to 6.180. I wouldnt use a drum under 6.160 and id want it over 6.170 for a high hp application. There is only one good way to turn one of these that i have found. A carbide cutter wont work either. Hydramatic ground them originally.

I will keep this in mind and check the drum OD when I tear it apart.

Yes I dont use the alto band anymore. If you cut the drum in a lathe you should use a ceramic cutter and it should be done on a fixture not by grabbing the Od or ID of drum. Best for the drum to be center ground. No smaller than 6.160 or 6.150 in an extreme pinch on a stocker. Or use a good used drum with a standard width Carbon band with as much carbon as you can get. Carbonite is not carbon it a Carbon Kevlar mix with very little carbon and is junk. You will be surprised how well the standard width works. I personally think its better than wide unless you have a fresh ground drum in a perfect world. As Otto stated if drum is cut you will need to mod the pin to add length.

I think I am going to try a stock width band this time. I have a couple of uncut used drums.

What are you running for boost valves in the pump?
If its not a BRF trans they could be really small

I don't remember, but they came in a kit I got a few years ago from 700R4 & 4L60E Automatic transmissions specialists - ProBuilt. They don't offer it anymore, but it was supposed to hold 550hp.

 

[bison]

Ive found you cant always zero out trying to hold it by the bushings since they may not be totally square in the the bores. If you cut .030 id throw the drum out. Too much imo.

 

[quickt]

I think I am going to try a stock width band this time. I have a couple of uncut used drums.

Call me I will send you one

 

[LOT]

?

Do you have a hole (.060 or so) drilled in the direct drum?

 

[forkspear]

Do you have a hole (.060 or so) drilled in the direct drum?

Yes I drilled a bleed hole

 

[forkspear]

Ive found you cant always zero out trying to hold it by the bushings since they may not be totally square in the the bores. If you cut .030 id throw the drum out. Too much imo.

That had crossed my mind but I did not want to drive the bushings out because I did not have new ones at the time. The only way I checked the diameter of the drum was wrap the band around it and squeeze it together. There was still a gap between the ends but not as big as I would have liked. I am going to check my other drums. What is the max runout and taper allowed?

 

[bison]

That had crossed my mind but I did not want to drive the bushings out because I did not have new ones at the time. The only way I checked the diameter of the drum was wrap the band around it and squeeze it together. There was still a gap between the ends but not as big as I would have liked. I am going to check my other drums. What is the max runout and taper allowed?

i dont know if there are specs for run out or taper since the item isnt intended to be serviced. Id want less than .003 myself though. More may be ok. Im sure there is some deflection when the band applies. There is some clearance between the support bushings that will allow a slight cocking of the drum but its neglible. The important thing is that the band gets a good initial grab on the drum. I see a lot of tapered drums. Some over .010 The only time i see this is when the drums have been turned. Likely with the wrong type of cutter and cutting too much at once. I take off the minimum. Sometimes its a .003 cut.

 

[forkspear]

i dont know if there are specs for run out or taper since the item isnt intended to be serviced. Id want less than .003 myself though. More may be ok. Im sure there is some deflection when the band applies. There is some clearance between the support bushings that will allow a slight cocking of the drum but its neglible. The important thing is that the band gets a good initial grab on the drum. I see a lot of tapered drums. Some over .010 The only time i see this is when the drums have been turned. Likely with the wrong type of cutter and cutting too much at once. I take off the minimum. Sometimes its a .003 cut.

That was about how much I took off a cut too. On the final cut i turned the speed all the way down and let it go over it twice without changing anything. I thought it came out pretty good. Except the diameter is probably too small. I am debating on trying it on an uncut used drum and running a wide band again or trying quickt's narrow carbon band. or buying a rebuilt drum.

 

[forkspear]

Call me I will send you one

how much?