700R4 shifts erratically

[MGD454]

Hey all, this is my first 700R4. It had a whole bunch of nastiness in the pan when I first got it and changed the filter and fluid about 3 months ago. I have also replaced the TV cable and adjusted it to spec. I have removed and cleaned the 1-2 shift governor to ensure proper movement of the internal parts.

My problem is it will shift perfectly sometimes and other times it won't shift 1-2 or 2-3 unless I'm at or higher than 3000 rpm. There is no slippage of any of the gears/clutch packs. When it does shift, it shifts good and hard, so I don't think I need a rebuild.

Am I thinking correctly that there may be more gunk in the valve body not letting the pistons/rods move freely and it's taking a higher rpm to get the pressure up to move them if they are stuck?
Can I just remove the valve body, clean and ensure things move freely and replace?
What is your opinion on having it back flushed?

Thanks for any input you guys have.

 

[Chevy 88]

Sounds like its just about toast to me.

Back flushing would work pretty well if your trying to finish it off as quickly as possible.

 

[Beast496]

How much material in the pan are we talking about? was it magnetic? as said above, you're better off not wasting money on a flush unless, you want to get it as clean as possible before you tear it apart for a rebuild. I suppose you could try to drop the valve body and see how free everything is, but I wouldn't hold my breath. once things start to go, its usually not long.

 

[MGD454]

I would say a thin layer of black dust like substance. I didn't notice too much metallic stuff. It seemed like normal wear of the clutches in a trans that hasn't had a changed filter in about 50,000 miles.

 

[Beast496]

I would say a thin layer of black dust like substance. I didn't notice too much metallic stuff. It seemed like normal wear of the clutches in a trans that hasn't had a changed filter in about 50,000 miles.

If it was me, I still wouldn't do a flush. If I felt it still had life in it, I would drop the valve body, thoroughly clean it, bore brush all the passages, polish everything up, and put it back together with a new filter and gaskets. Then put a pressure gauge on it when you take it for your test drive and see where your line pressure is at in all gears.

 

[legopnuematic]

line pressure is at in all gears

100% checking pressures should provide some insight to what is going on inside. With that data it should provide a good direction to move forward with.

 

[NickTransmissions]

Hey all, this is my first 700R4. It had a whole bunch of nastiness in the pan when I first got it and changed the filter and fluid about 3 months ago. I have also replaced the TV cable and adjusted it to spec. I have removed and cleaned the 1-2 shift governor to ensure proper movement of the internal parts.

My problem is it will shift perfectly sometimes and other times it won't shift 1-2 or 2-3 unless I'm at or higher than 3000 rpm. There is no slippage of any of the gears/clutch packs. When it does shift, it shifts good and hard, so I don't think I need a rebuild.

Am I thinking correctly that there may be more gunk in the valve body not letting the pistons/rods move freely and it's taking a higher rpm to get the pressure up to move them if they are stuck?
Can I just remove the valve body, clean and ensure things move freely and replace?
What is your opinion on having it back flushed?

Thanks for any input you guys have.

Let me help you with some terminology:

1. "1-2" shift governor - not sure what you're referring to but the likely relevant parts are the 1-2 accumulator housing, governor or 1-2 shift valve/throttle valve train in the valve body

2. "Rods and pistons" - lol, the valve body isnt an engine. Valves, springs, plugs and roll pins are found in the valve body

As to your issues:
1. Check your line pressure, preferrably while driving - let us know what the results are. You should see 50-75 PSI at idle in P, N, D, D3; 85-120 in Reverse and 120-170 in D2 and manual low (D1). As soon as you start to move, line pressure should spike to double-triple the values at idle.

2. Pull the governor and check the governor valve - if the valve isnt moving freely when working the weights in your hand, remove/replace the governor gear (it's prob worn) and then the valve. Polish the bore w/bench buddies and WD40 until the valve moves freely.

3. Valve body - If the governor is already fine or servicing it doesnt work, pull the valve body and overhaul it - install a Transgo SK700 Jr shift kit. There are several corrective parts that address common issues, including those in the valve body

4. If none of the above works, yank it for overhaul - it's done.

 

[MGD454]

Thanks Nick, this is what I am referring to for my terminology. Sorry, governor, valves and plungers, I don't work on transmissions for a living, I'm a machinist.

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[MGD454]

Update--I pulled the pan this weekend and there were chunks...
It's getting a complete rebuild along with the transfer case so at least I know those two pieces of my drive train will be reliable. Going in with a 6.0 next.

 

[MGD454]

With that being said, @NicksTransmissions, I read your post on what all is needed for a rebuild. Is there a place to get the rebuild kit with all the stuff needed that you put on that thread? I can get the tools (already have some of those) but the specific internal parts, I'm wondering if it would all come as one kit or do I need to piece it together to get what you recommend? Local shops here in Colorado want $2200-$3600 to rebuild, (not sure they'd put all those parts in) and that's if I just give them the trans out of the truck.

 

[NickTransmissions]

With that being said, @NicksTransmissions, I read your post on what all is needed for a rebuild. Is there a place to get the rebuild kit with all the stuff needed that you put on that thread? I can get the tools (already have some of those) but the specific internal parts, I'm wondering if it would all come as one kit or do I need to piece it together to get what you recommend? Local shops here in Colorado want $2200-$3600 to rebuild, (not sure they'd put all those parts in) and that's if I just give them the trans out of the truck.

Yes, you can look through the kits that are on eBay - most of them are being sold by Transpartswarehouse.com...TPWH is one of the largest transmission parts retailers in the country; Transstar is another such large retailer with. some brick and mortar distribution hubs...Based in Redding, CA, Transpartswarehouse.com will have complete kits as well as individual soft and hard parts that can be purchased as you need them.

Here's the parts I'd install in your 700R4, assuming it's a 1987+ model year unit) if I were to rebuild it for <=350 HP in a street-driven application:
- 700R4 Overhaul kit (gaskets, seals, o-rings, sealing rings, etc)
- 700R4 filter
- 1997+ 4L60E steel module
- 1997+ 4L60E Borg Warner clutch module
- Alto Wide Red band
- New reverse input drum (the 700r4 rev input drum is obsolete so you'll end up with a new 4L60E rev input drum, which will retro to all years of 700r4)
- 4L60E viton/rubber lube seal for the forward drum
- 1997+ bonded piston kit and forward/coast clutch dual retainer piston return spring assembly
- Sonnax Smart Tech sun gear reaction shell
- 700R4 Transgo Jr Shift kit
- Sonnax 700r4 throttle valve sleeve and plunger kit
- Sonnax .500 boost valve and .283 reverse boost valve (these come w/o-rings to seal off the boost and rev boost hydraulic circuits)
- Sonnax corvette 2nd gear servo (you don't need their billet super hold servo - that's for anything north of 500HP street/strip or full race)
- Transgo 700P separator plate (follow the instructions that comes w/the plate and shift kit for proper mechanical calibration)
- new 1-2, forward and 3-4 accumulator pistons (large hole)
- New governor gear
- Complete bushing kit + Durabond wide rear sun gear bushing
- wiring harness w/TCC lock up solenoid
- case connector
- Pump vanes
- Pump 10-vane rotor guide
- Remachined stator support and pump body

If there's anything else I can think of, I will edit this post.

Let me know if you have any ?s