Torqueflite slipping? Pls check the pan, need advice.

D

DLJ

New member
I hope this is not off topic once my torqueflite is the a-904-la behind a 318 rwd v8
the tranny is a 1976 stock, never opened until now, it has around 90,000 miles from which only 8,000 miles driven by myself.

I found the forum o be the most informative and thorough I have been through and thats why I decided to post here.

Once the car is a kinda collection vehicle now, I just want to keep it running after a long 15 years garage sleep.

The only complaint I had from the time I was driving the car is that it always felt like slipping in 3rd (d) when climbing uphill steep roads, it would show a 500 rpm increase for the same speed.
40 mph shows 2,000rpm and 2,500 rpm on a steep road
50 mph shows 2,500rpm and 3,000 on a steep.

I am not sure if the rpm increase could be due to a sound reason like the stock non lock up torque converter, or something else.

Neither it slips in reverse nor in 1st gear (so, front and rear clutches are ok? Bands I could see are ok and overruning clutch should be good).

I finally droped the pan and took the valve body out to look at the bands and drums and for my surprise, fluid was pretty dark but still red, not burnt, inside case walls clean and the bands where not loose ( I am pretty sure no one touched the rear band).

https://imageshack.com/I/iqommyfej

The pan has no magnet and had quite a bit of residue which is what concerns me, link below for the pics of the pan as it was dropped.

https://imageshack.com/I/ex1dz5zhj

Looks like alot of gunk but after scraping it to 1 pile I think it was not too bad, perhaps...?

https://imageshack.com/I/idnhggqtj

https://imageshack.com/I/iqmn6fbej

(scroll album left for 904 pics, right to 46re another issue)

another detail is that when I bought the car I recall the throttle rod was off almost 3/4" and I thought it was supposed to be like that (never had a tranny manual or tranny experienced mechanic). Tranny always shifted great at right speeds, good kickdown, no complaints except the slipping on steep.

Here is a link to a 1st set of pictures I took showing the pan residue I'd like to be commented for someone experienced if possible.

I have collected all solid residue, washed it in solvent and filtered through coffee filter and sifted to separate coarse from fine particles. I'll post some pics of the residue later if anyone in interested.

https://imageshack.com/I/p4yvxpjbj

https://imageshack.com/I/idrbwsw4j

https://imageshack.com/I/f0s7g0thj

I plan on installing a transgo tfsc shift kit, adjust bands, place magnet in pan, new manual shaft seals, new rear seal, new filter and fluid, adjust throttle rod and re-check slipping condition.

https://imageshack.com/I/f0oask2mj

Any advice would be appreciated...
 
Looks like an awful lot of contamination. That trans is clearly in need of service. If you haven't separated the valve body halves for inspection, that should be done also, as the internal fluid passages have likely trapped a fair amount of sludge. The vb innards need to be whistle clean and each valve must move freely inside its bore. What you can't inspect without unit removal and complete tear down, is the condition of the friction discs inside the front and rear clutch assemblies. While your bands May still have an acceptable amount of resident friction material, there's no way to ascertain clutch disc condition without going deeper. Anything short of that is guessing. Some of that sludge came from the bands, but not all of it. Given the mileage and contamination level, this unit is a prime candidate for complete overhaul. Your planned modifications would really be more effective in conjunction with an overhaul rather than a band-aid fix.
Not knowing your axle gear ratio and tire size makes commenting on your road/engine speed observations a bit tricky. As an example, a vehicle with 28" diameter tires and a 3.54 to 1 axle gear ratio, would have an engine speed of about 2125 rpms at 50 mph in direct drive on a level surface. Hill climbs obviously increase engine load, requiring an increase in throttle pressure to maintain a given road speed. Engine and road speeds will often taper off just before the moment that applied throttle pressure combined with increased engine load induces a downshift from direct to 2nd. This would naturally be accompanied by a sudden increase in engine speed of several hundred rpms and stronger acceleration up the hill. If your revs are increasing by 500 as you climb a hill with no corresponding downshift from direct drive, I would consider that abnormal. All indications point to the same conclusion in my mind.
 
Thank you much scoutboy74 for the input.

If clutches are slipping, could I tell it running a stall test?
My guess would be either clutches slipping or normal tc slippage increase due to driving up steep hill (perhaps low line pressure too).

The fact is that the transmission has not been in use since about 15 years ago, it is a stock 1976 a-904-la and since it ran and shifted fine around the block last month, and I recall it was not slipping in reverse nor in low d or 1 I assume the clutches were still holding ok. It always worked fine, the only complaint was the rpm increase in 3rd gear when going uphill.
As per the preserved state of the bands (which surprised me alot compared to my other 46re with 60,000 mi) I was guessing the front clutch could be slipping in 3rd gear when climbing uphill.

Another factor is that I noticed the throttle rod adjustment was a bit short (about 1/4") so line pressure could be a bit lower:

https://imageshack.com/I/ex4c1bbwj

I know the transmission is a candidate for rebuilt but once the car is driven only to keep it running and parts here are really rare and expensive, I really don't want to pull it if it is still working ok.
I have finished doing the vb transgo tfsc kit, pictures of the vb parts are on same gallery and for my surprise the inside of the vb did contain very little amount of fine particles and all moving parts were free.

imageshack - dscn2274.jpg

imageshack - dscn2273.jpg

imageshack - dscn2272.jpg

After cleaning, put it back and added 2 magnets in the pan:

https://imageshack.com/I/p4gvuoimj

https://imageshack.com/I/iqvklgtfj

https://imageshack.com/I/exhwozpoj

https://imageshack.com/I/f0tuly9xj

https://imageshack.com/I/f0kubwtrj

Now I am in the process of changing the rear seal and fill it with fresh dexon II for a road test so I can verify after 15 years if something has changed.
 
Nice job on the cleanup. The vb looks much better. I understand what you're trying to accomplish and hopefully the function will be improved as a result of your efforts. Fresh fluid, filter, some cleaning and adjustments in spec might coax an extended interval of limited usage out of it.
 
I just wanted to let other people that May have seen this thread know that after cleaning the valve body, adjusting bands and linkages (that were not far by the way), new rear and manual shaft seals, filter and fluid, my 38yo torqueflite a904-la transmission is not slipping at all, except for the non lock up torque converter.

The pictures I posted before, imageshack links show my 1976 torqueflite had substantial amount of particles in the pan because it has never been serviced and it did not have a pan magnet (around 85,000miles).

I did install a transgo tfsc shift kit but could not notice much difference besides a real quick 1-2 shift, which in my oppinion, is a bit harder than it should be.

The stall speed is a solid 2400 rpm with dexronii either cold or hot on d, 1 or reverse so I am happy it is pulling good and my corcern about slipping on steep hill roads (250 rpm increase in 3rd) must be due to the non lock up torque converter.

Once it is not a daily drive I hope it will last long...
 
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