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Re: "Built" 700R4 teardown. Poor quality and attention to detail.
What's up with the crazy heavy 3-4 accumulator spring? I had to put A LOT of air pressure on that sucker to get the piston out and it shot across the shop like a bullet. Doesn't seem like there was any real movement happening on that 3-4 accumulator piston. No wear to the Sonnax bore sleeve.
On the other hand, the 1-2 accumulator piston was obviously doing a lot of movement and the piston o-ring is SHOT as well as the bore sleeve being heavily damaged and grooved.
The low reverse clutch was slipping due to the rolled low reverse piston seal and having low pressure in reverse. A bunch of clutch material was evident and heavy contamination of the accumulator area was present as it sits below the low-reverse clutch pack.
The valve body gaskets were shifted and partially covering some holes. It was carelessly installed. Not centered or trimmed in poor fitting areas.
The trans shifted like a sledgehammer in 1-2. Not that I minded... but I had to be careful with throttle input if I wanted a reasonably non violent shift. It would easily break the tires loose on the 1-2. The rest of the shifts were ok, though it didn't downshift as quickly as my replacement 92 trans. This trans is a pre-87 without the aux valve body.
I swapped it and tore it down because of the reverse slipping. I figured best not to let it run till failure.
GD
Last edited by GeneralDisorder; 04-19-2019 at 01:00 AM.
Re: "Built" 700R4 teardown. Poor quality and attention to detail.
Originally Posted by GeneralDisorder
What's up with the crazy heavy 3-4 accumulator spring? I had to put A LOT of air pressure on that sucker to get the piston out and it shot across the shop like a bullet. Doesn't seem like there was any real movement happening on that 3-4 accumulator piston. No wear to the Sonnax bore sleeve.
On the other hand, the 1-2 accumulator piston was obviously doing a lot of movement and the piston o-ring is SHOT as well as the bore sleeve being heavily damaged and grooved.
The low reverse clutch was slipping due to the rolled low reverse piston seal and having low pressure in reverse. A bunch of clutch material was evident and heavy contamination of the accumulator area was present as it sits below the low-reverse clutch pack.
The valve body gaskets were shifted and partially covering some holes. It was carelessly installed. Not centered or trimmed in poor fitting areas.
The trans shifted like a sledgehammer in 1-2. Not that I minded... but I had to be careful with throttle input if I wanted a reasonably non violent shift. It would easily break the tires loose on the 1-2. The rest of the shifts were ok, though it didn't downshift as quickly as my replacement 92 trans. This trans is a pre-87 without the aux valve body.
I swapped it and tore it down because of the reverse slipping. I figured best not to let it run till failure.
GD
Is that a valve spring in there? Lol. Shady work definitely. Looks like he didn't prelube the area were the low reverse piston goes into folding that seal. Hey bud I got a question for you. When air testing the clutches, I put air to the 3-4 clutch hole on the pump and the clutches engage perfectly but I feel air coming from the forward clutch hole on the pump. Is this normal? Forward clutches do not engage btw. I don't quite remember from my first rebuild. Same thing happens in vice versa. If I apply air to forward clutches, they engage good but air comes out the 3-4 hole. 3 4s do not engage either. But just wondering if the air coming from there is normal.
Re: "Built" 700R4 teardown. Poor quality and attention to detail.
Well I'm no expert on this by any means, but looking at the power flow chart I see that in all cases where the 3-4 clutch is applied so is the Forward Clutch. So I would assume that both are receiving pump pressure at the same time and that being the case it would stand to reason that the two *could* be connected if the conditions are right in the valve body (Drive 3/4, and Manual 3). Again I'm no expert on the 700R4 - just observing and taking notes as I go. I'm interested in what Dana at Probuilt Automatic's has to say about it.
Re: "Built" 700R4 teardown. Poor quality and attention to detail.
Originally Posted by GeneralDisorder
Well I'm no expert on this by any means, but looking at the power flow chart I see that in all cases where the 3-4 clutch is applied so is the Forward Clutch. So I would assume that both are receiving pump pressure at the same time and that being the case it would stand to reason that the two *could* be connected if the conditions are right in the valve body (Drive 3/4, and Manual 3). Again I'm no expert on the 700R4 - just observing and taking notes as I go. I'm interested in what Dana at Probuilt Automatic's has to say about it.
Re: "Built" 700R4 teardown. Poor quality and attention to detail.
The stiff spring in the 4th accumulator, is when installed first will effectively eliminate the accumulation. The spring when installed first does not have to be stiff. The easy way is to block the feed hole in the 4th accumulator. When the forward clutches are on, (they are always on when in any forward shifter position) they will be affected by throttle change, which creates more or less pressure based on throttle position. As long as the transmission is built correctly, these clutches will not breakaway. When I install the valve body gaskets, or setup separator plates for kits, I make sure that the gasket has not shrunk or expanded, and open any holes that are partially blocked, especially when you open up the feed holes on the separator plate. When installing the separator plate on the case, make sure that the feed holes do not run into any of the partitions in the case. Modify the partition to make sure that is out of the way. Only remove what is in the way, nothing more. If the input shaft seals are not sealing properly against the stator tube. You will have to check closely the condition of the seals and the inside of the stator tube to make sure it is in good shape. Anything else here, let me know.
Re: "Built" 700R4 teardown. Poor quality and attention to detail.
It looks like the 3/4 accumulator feed hole has been blocked. Do I still need this crazy spring or can I just use a stock spring?
What do I do about the 1/2 accumulator Sonnax sleeve that's badly grooved? Do you reccomend using the Sonnax accumulator piston and sleeve kit on a replacement 1/2 housing or just get a good used housing and use a stock piston with a regular non o-ring seal?
Re: "Built" 700R4 teardown. Poor quality and attention to detail.
When blocking the 4th accumulator, you do not need to install a piston, pin, spring assembly. Get a 4L60E 2nd accumulator housing instead of the700R4 setup. If you want this an HD setup, get a .471" or .500" main boost valve, .296" intermediate/reverse boost valve, Corvette servo, 2nd accumulator piston (aftermarket) and the 700R4 TransGo Junior Shift kit. If you want me to supply this I can with much more that I do here. I have the necessary HD instructions for this, and I can email them to you, if you decide to do this yourself. This will make a big difference in how this works.
Re: "Built" 700R4 teardown. Poor quality and attention to detail.
I will take stock of what I have here and give you a call. The trans has a Sonnax servo, and it has the TransGo boost valves. The separator plate has been drilled and it has had work to the valve body for sure.... has 5 pinion planetaries, and a Beast sun shell also. Most of the clutches are in great condition - I think just the low/reverse got wasted because of the rolled seal and the 2nd accumulator is shot.
04-19-2019, 12:53 AM
