[cv70chall]

During our "shakedown drive" the tranny was having trouble going into 3rd- and when it tried to a couple of times, it slipped.
I checked the throttle pressure/ adjustment and it's not the issue and decided to try some Lucas non-slip/ conditioner and see if maybe the issue might be gunk in the valves.
This transmission worked fine when removed so what might it be?

[dave-r]

Check the band adjustments.

[dave-r]

In particular the front clutch (kickdown) band. It is right next to the shifter lever on the left side of the trans. To adjust just back off the lock nut, tighten the adjustment nut up GENTLY and just nip it up not much more than finger tight. Don't put any real weight on it. You are just seating it firmly.

Then back the adjuster off 2 1/4 turns and hold it steady while you tighten the lock nut.

[dave-r]

Make sure the fluid level is correct first though. If it is low it will do the same thing.

[dave-r]

Those are the only two things I can thing of that don't involve draining the oil and removing the pan.

[cv70chall]

Thanks Dave-

Fluid level is fine so I'll try to band adjustments. If that fails, what am I looking for with the pan/ filter removed? (These are newly replaced as well)

[dave-r]

One thing at a time. Adjust the front band first and try again.

[transman]

If the suggestions others have given you don't cure the problem, and you drop the pan, look for clutch plate/steel plate sludge/etc. in the oil. The reason I mention this, is you didn't say, what if anything ,you had done to clean out the transmission cooling lines and the transmission cooler, either the one in the rad, or if you had one, an outboard cooler.
Many times, the cooling system is NOT CLEANED properly and all the crud from your pre-rebuilt transmission remains in it. Some will tell you to blow solvent or some other cleaning product through the lines and that will take care of any dirty cooling system issues. Not so. What most don't know, is that ATF is one hell of a high detergent and once it warms to transmission operating temp, it cleans everything out.
If when you tore your transmission down, there was crud in the pan, to make sure everything is nice and clean in the cooling system:
A: take the rad to a rad shop and have a new cooler installed in it and
B: if it's got an aftermarket cooler on it, chuck it in the trash can, as they are very hard to clean
C: if it's only got an aftermarket cooler on it, again chuck it in the trash and get a new one.

This guys, comes from 25+ years in the transmission business. The company I worked for, sold among other tools, a $7000.00 + machine that ONLY cleaned transmission cooling lines and transmission coolers. I did a demo for one of my customers on a unit that he swore up and down was clean. This was a Ford dealer, and they had used the tool that Ford supplied them. It used ATF (not heated) and air. After 30 minutes with the machine hooked up we examined the filter in the machine. He couldn't believe how much stuff they didn't get out, and gave me an order on the spot for a machine.

I know that the average car buff isn't going to purchase a specific use machine, but you might want to consider options A, B, & C.

Just my 2 bits worth.

transman

[cv70chall]

Hey thanks for the tips.
Actually, when we cleaned it- we replaced the gaskets and filter and there was not much in the way of sludge in the pan. Actually quite clean.
We added a transmission cooler later on, and it was pristine. New lines as well.
I believe this may have been evident long before I was able to drive the car again (it basically sat undriven for 3 years).
Either way, I have a replacement I plan on swapping out with my bad one.
One question though-

Can I drive the car to the shop we used to work on it with the tranny behaving the way it is? It'll only go into 2nd- fluid is obviously burnt, etc.
I basically need to drive it about 12 miles and then we yank the tranny out.
Safe to do this one last time or not?

[transman]

If you take it easy, I see no reason not to drive it. It's only 12 miles, but with that being said, you just don't know when it will die on you. It may or it may not, it's your call. With burnt fluid, and you say it sat for 3 years, I'd guess that the lip seals are toast. Transmissions need to have the juices run through them, and sitting for 3 years the seals can become mis-shapen and allow the fluid to by-pass and cause a slipping condition which can burn the fluid etc. My Challenger sits for 6 months out of the year, but on nice days, I back it out of the garage and run it for about an hour. During this time, I make sure that I drive it up and down the driveway and run it through all gears.

transman