Brain
Well-Known Member
- Joined
- June 14, 2004
- Messages
- 915
- Reaction score
- 4
- City, State
- Golden, CO
- Year, Model & Trim Level
- '92 4X EB and '91 4X XLT
On to the intermediate drum and the reverse/high clutch pack.
Here's a view of the front of the A4/4R version:
And here's the front of the 5R version:
You can see that the A4/4R has the bushing in the center where the drum rides on the center support snout, where the 5R version has a steel race for the snout roller bearings.
Another improvement is how thickness of the lugs at the back of the drum has increased (look at the bottom):
Here's a shot of how the thinner lug of the A4 actually deformed the metal of the input shell. The 5R version had no deformation at all as far as I could tell.
Here's another shot of that deformation:
Now to the other side. Here's a pic of the back of the drum with a thrust washer in the A4 (note that the clutch plates are not in place in this pic):
Here's the drum out of the 5R with a Torrington bearing in place of the thrust washer:
Here's a closeup of the channels that carry the steel clutch plates for the reverse/high clutch pack in the A4:
Here's a closeup of the channels that carry the steel clutch plates for the reverse/high clutch pack in the 5R:
Notice that the shape of the channels that carry the steel clutch plates in the drum have been changed with a triangular back so that fluid has an easier time getting out of the clutch pack when it is applied (when fluid needs to get out of the space between the friction plates and the steel plates).
Here's something that I didn't catch on the teardown of the 5R:
That's right, only four friction plates in that clutch pack. If you look up at the drum pictures, you can see that the top of the pack is lower in the 5R than in the A4. I'd like to get at least five, if not six plates in this pack, so I'll update this when I pull the pack apart and find a way of making it happen.
[Update]
I pulled this clutch pack apart for two reasons. The first reason was to see if the piston size had been increased because there were fewer friction plates - the piston was the same. The second was to see how I could get more friction plates in there (at least five).
When I disassembled it, I saw somthing that was hidden before (by the top pressure plate). Here's the components (minus the drum and piston):
Here's a closeup of the edges of the steel clutch plates:
These are different plates than are in the A4, as they have small semicircles removed from the edge of the engagement tabs. This, together with the v-groove in the drum, make for a pretty big pathway for the fluid to get out when the clutch is engaged.
The stock A4 steel plate thickness (0.065"):
The stock 5R steel plate thickness (0.081"):
I found information that shows four thicker (0.081") steel clutch plates for the OHV engine, which means that four friction plates would be normal also. I still want five, so I'm working on some combinations of steel plates to make it work. There isn't enough room at the bottom to take material off the top of the piston, so it has to fit up beneath the groove cut in the drum for the snap ring.
I am going to upgrade the inner snap ring retainer with a full-surround unit (which they used on the overdrive clutch pack, but not on the rev/high clutch pack for some reason). Here's a picture of that part:
[Update #2]
I found out that there are two sizes of piston (and corresponding drum) for the reverse/high clutch. The two parts listed are XL2Z-7D044CA for the small piston used on the SOHC, and XL2Z-7D044AA for the larger piston used on the DOHC. The one that came out of this tranny was of the large piston variety (AA). Maybe the ones with large pistons only had four frictions and the small piston variety had five, but this is only speculation.
The other part of this update concerns the way I'm going to get five plates into this clutch pack. I'm going to use the thinner steel plates (.065s instead of the .081s) as well as cutting the retaining plate back around the large snap ring to 0.125" (stock is 0.200"), while still using a 0.065" thick snap ring. There isn't any room to go any further forward on the splines on the forward clutch drum (as shown below), so I'm having to go back on these splines, which means making the clutch plate stack taller by adding to the top instead of adding to the bottom. Getting five plates to work will require some pretty simple machining, but getting six to work would more than quadruple the necessary effort, so I'm going to be OK with just five (only 25% better than stock ) . If anybody needs to have me turn down a separator plate for them, PM or e-mail me. I'll update this with pics when it is done. BTW, I think I'm going to end up with 0.075" of metal from the separator plate in the channel (meaning it won't spin around in the snap ring groove).
Here's a view of the front of the A4/4R version:
And here's the front of the 5R version:
You can see that the A4/4R has the bushing in the center where the drum rides on the center support snout, where the 5R version has a steel race for the snout roller bearings.
Another improvement is how thickness of the lugs at the back of the drum has increased (look at the bottom):
Here's a shot of how the thinner lug of the A4 actually deformed the metal of the input shell. The 5R version had no deformation at all as far as I could tell.
Here's another shot of that deformation:
Now to the other side. Here's a pic of the back of the drum with a thrust washer in the A4 (note that the clutch plates are not in place in this pic):
Here's the drum out of the 5R with a Torrington bearing in place of the thrust washer:
Here's a closeup of the channels that carry the steel clutch plates for the reverse/high clutch pack in the A4:
Here's a closeup of the channels that carry the steel clutch plates for the reverse/high clutch pack in the 5R:
Notice that the shape of the channels that carry the steel clutch plates in the drum have been changed with a triangular back so that fluid has an easier time getting out of the clutch pack when it is applied (when fluid needs to get out of the space between the friction plates and the steel plates).
Here's something that I didn't catch on the teardown of the 5R:
That's right, only four friction plates in that clutch pack. If you look up at the drum pictures, you can see that the top of the pack is lower in the 5R than in the A4. I'd like to get at least five, if not six plates in this pack, so I'll update this when I pull the pack apart and find a way of making it happen.
[Update]
I pulled this clutch pack apart for two reasons. The first reason was to see if the piston size had been increased because there were fewer friction plates - the piston was the same. The second was to see how I could get more friction plates in there (at least five).
When I disassembled it, I saw somthing that was hidden before (by the top pressure plate). Here's the components (minus the drum and piston):
Here's a closeup of the edges of the steel clutch plates:
These are different plates than are in the A4, as they have small semicircles removed from the edge of the engagement tabs. This, together with the v-groove in the drum, make for a pretty big pathway for the fluid to get out when the clutch is engaged.
The stock A4 steel plate thickness (0.065"):
The stock 5R steel plate thickness (0.081"):
I found information that shows four thicker (0.081") steel clutch plates for the OHV engine, which means that four friction plates would be normal also. I still want five, so I'm working on some combinations of steel plates to make it work. There isn't enough room at the bottom to take material off the top of the piston, so it has to fit up beneath the groove cut in the drum for the snap ring.
I am going to upgrade the inner snap ring retainer with a full-surround unit (which they used on the overdrive clutch pack, but not on the rev/high clutch pack for some reason). Here's a picture of that part:
[Update #2]
I found out that there are two sizes of piston (and corresponding drum) for the reverse/high clutch. The two parts listed are XL2Z-7D044CA for the small piston used on the SOHC, and XL2Z-7D044AA for the larger piston used on the DOHC. The one that came out of this tranny was of the large piston variety (AA). Maybe the ones with large pistons only had four frictions and the small piston variety had five, but this is only speculation.
The other part of this update concerns the way I'm going to get five plates into this clutch pack. I'm going to use the thinner steel plates (.065s instead of the .081s) as well as cutting the retaining plate back around the large snap ring to 0.125" (stock is 0.200"), while still using a 0.065" thick snap ring. There isn't any room to go any further forward on the splines on the forward clutch drum (as shown below), so I'm having to go back on these splines, which means making the clutch plate stack taller by adding to the top instead of adding to the bottom. Getting five plates to work will require some pretty simple machining, but getting six to work would more than quadruple the necessary effort, so I'm going to be OK with just five (only 25% better than stock ) . If anybody needs to have me turn down a separator plate for them, PM or e-mail me. I'll update this with pics when it is done. BTW, I think I'm going to end up with 0.075" of metal from the separator plate in the channel (meaning it won't spin around in the snap ring groove).