The Dodge Challenger Message Board

As described in the EuroNats thread we didn't run any faster this year despite 4.30 rear gears and extra gears.

I could not figure out what was going wrong at first. Other people were complaining their mph was down but it seemed more than that to me.

So as an experiment I asked Linda to drive it again but to not use the overdrive until running out of revs in third (drive). The way the car is geared it will do 117mph in third so if she needed to shift to overdrive before the line she must be doing at least that speed.

Here is what Linda says about that run;

"And it seemed like the
shift light to shift into 3rdover came on bang on the line or just
after. I
remember because I kept waiting for it to come, expecting it, & it
didn't
come for ages."

So the car was indeed reaching the top of third gear. But the terminal speed was only 110mph.

Linda carries on...

"What happened in the runs before was that it all went ok until the
shift into 3rd, & instead of feeling like it was pulling forward, it felt like the engine
was surging & the car not pulling."

"On the last run on Sun am, that rev surge also happened as I got into high revs in 1st."

I checked the fluid level and all seems well.

So my thoughts are that the clutches are slipping.

When i first re-built this trans I made a mistake and the trans was slipping a lot. This wore the friction material and heated the metal spacers so much i had to replace two of them.

I put the mistake right but used the same friction material.

Does everyone agree that this is probably the cause of my grief?

The other question is should I replace the friction material with B&M material the same as what is in there now? Or should I replace them with Raybestos? The problem with the latter will be getting the right amount of clutch plates in because they are thicker and I don't want to get into machining at this point.

I forgot to say that the mistake i made was leaving off the piston seal for the rear clutch. This caused the rear clutch to slip badly. When i realised what i had done I fitted the seal and it seemed to work ok.

I think I am right in thinking that a slipping rear clutch would cause the problems described by Linda above??

From what you've said you've probably got a cut lip seal on the front clutch piston. This will cause a slipping condition. I'll bet you're also right that the fibre frictions are burnt, and the steel plates most likely have heat marks on them too.
I'm not aware of different thickness plates for that drum, that would make any real difference to your clutch pack clearances. Typically they measure .091 to .097 thick, and Raybestos are the OEM plates Chrysler uses.
I've measured the friction plates from 3 different suppliers, and the measurements are as follows.
Raybestos (stock) .094
Raybestos (blue racing plates) 0.94
Borg Warner (non racing) .095
Alto (red racing plates ) .095
If you want to put more frictions in the front clutch drum, rembember that there were 3 different ones, a 3 friction drum (most common in the 727), a 4 friction drum, and the 5 friction drum (most rare, except it is now available in the aftermarket, made from steel, not cast iron. You can modify the 3 pack drum to accomodate 4 frictions, by having a machine shop cut a grove higher up in the drum. Make sure though that the person doing this is knowledgeable.
Just a little reminder Dave, when you install lip seals on a piston, make sure you use lots of assembly lube, common everyday vasoline works just fine and dandy.

Nothing to add Graham. Try to get your hands on one of the movies made while you were running. Maybe then you can explain some things by listening to it.

In fact, before I rebuilt mine I had extremely slipping, it sounded like the trans was shifting to neutral and then to the next gear. Not that weird as when we were rebuilding the trans we found out there were 4 plates in a 5plate drum... So nice to read your message above Graham. (long time ago by the way )

Yeah mine is the 4 friction drum. I think the easiest way forward for me (and after talking to Duncan Watts our UK 727 expert) is to just get the B&M overhaul kit. It has all the friction and steel plates as well as the seals and gaskets for $125 and as the trans has the B&M stuff in it anyway it should be an easy swap with the right thickness retaining clips etc.

Duncan has plenty of spare parts if i find it was a loss of pressure due to wear on the pump or drum etc.

For people in the UK (or even maybe Europe) you can find Duncan at http://www.dwatts80.fsnet.co.uk/

Well I tried to order the B&M overhaul kit but they only list kits for the 1971-77 727 Trans!

So I ordered a TCI rebuild kit.

The TCI kit was the one I went for Dave, when Duncan rebuilt my trans. Bit more expensive, but running like clockwork so far.

Good luck.

I suspect that the B&M kit would have all the bits I need as I don't think there is much difference in these main parts from the early '60s up to the late '70s (except for the late '70s lock-up type). I could be wrong though so I played safe with the TCI kit. My only problem will be I will probably need a different thickness circlip to hold the clutches in. If so then I am hopeing Duncan can supply me one. But it means it won't be a one day rebuild as I hoped. I might be struggling trying to get the trans in and out of the car without anyone to help too.

The friction plates in the front pack, and the rear pack are the same from 1962 to present date.
The overhaul gasket set is the difference. There are two for the 727. 1962 to 1970, and 1971 to present date. If you have trouble getting the snap rings that hold the plates into the drums Dave, let me know and I may be able to help you.
Either drop me an email here at home, or at work graham@tcsproducts.com. I'll be back at work Tuesday.

Thanks Graham.

dave if you need a hand give me a ring

Will do Trev thanks.

I'm on holiday next week Dave. If you haven't made a start by then, I'd be glad to come and help.

ps- I don't know the first thing about rebuilding transmissions, but I'm happy to help lift heavy stuff.

That is VERY kind of you Tim. It is just getting it down from the engine and back up again that is tricky on your own. Especially the getting it back up again! I will let you guys know when the kit arrives. It should be despatched today and might land early next week.

The trans rebuild kit just arrived this morning.

Do you have any plans to strengthen the trans or are you only going to rebuild it?

I built it to B&M street/strip specification a couple of years ago but this does not strengthen it. There are always bits you can replace with stronger units but you have to draw a line somewhere. I feel the standard 727 built to stock 440 or Hemi spec is as strong as you need for the sort of performance level I am at. Time will tell!

More important is making sure everything is within spec.

What the....????

That is the inside of my trans pan.

Nice color eh? Kind of gun metal grey. Always liked that colour. But not for trans fluid!

Some of the metal pieces could be from where I had to do some drilling/tapping first rebuild. I did give the trans case as good a clean as possible but is is possible there was some chaff hiding somewhere? Not that much I though and it does not have the curved look you would get with drill swarf.

The orange bits look like they came off the sealer I used on the cork pan gasket.

The big grey chunks and the grey stuff in solution are friction material I think.

so I guess you did"nt service the box when you fitted the overdrive.

I didn't have to remove the trans to fit the overdrive. It seemed to be working OK and it was rebuilt just a few years ago so....

I should have passed a magnet over those bits of metal to see if they were steel or ally. That would have told me a lot. Too late now as I cleaned the pan already.

I hope you get it sorted, Dave. What does the trans filter look like? Is it clogged?

Looks the same as the bottom of the pan so I guess it was not flowing as well as it might.

Want a spare 904?

Dave. Make sure that you replace the transmission cooler(s).I don't know if you are running both the cooler in the rad, and an external cooler, but both will have to be replaced.
The only thing that will clean that junk out properly is transmission fluid, that is at operating temperature. To quote Lou Darling (a Daimler-Chrysler engineer) the world's record for the number of transmissions it takes to properly flush a cooler line properly is seven.
Don't take any chances Dave. You've got a lot of $$ tied up in your vehicle and to not properly clean the lines and coolers would be a waste of your valuable time and money.
I'd also like to point out that the old method of using solvents, varsol, etc., never were any good.
Just thought you might like this info.
Graham

Cheer me up why don't you.

Funny enough the fluid dripping out of the cooler lines is as clear as a bell. The pan is a DEEP steel item and I am crossing my fingers that all this sludge was held in the bottom of it.

I know you are not going to like this but flushing out the cooler (I only have the external one) is the only real choice I have. I will be lucky if i can find the cash for the new trans fluid. What I do have is access to a considerable amount of solvent.

I am just going to have to chance it mate. It is my only choice. If it all goes wrong for me then Duncan Watts (our UK Mopar trans expert) will be rebuilding it next year when I have saved some money (I get lots of overtime in the winter) and I can get a new cooler and lines then.

But for now I just want to get it running again. The weather is fine and I have something to prove to myself...

Looks like the clutches are shot Dave! Have any of you seen this new book? hot off the press I only got it 2 days ago from Amazon, an excellent 230 page job with hundreds of pictures and up to the moment tech on the latest race stuff and all the stock stuff too! If you are going inside your torqueflite ,you need this!