needing opinions on a c5 trans.

Topic: needing opinions on a c5 trans. (Read 2592 times) previous topic - next topic

needing opinions on a c5 trans.

August 19, 2009, 07:16:16 PM

I currently have a 79 F150 4x4 longbed, 351m, auto. (gas guzzler) I also have an 86 thunderbird with 289hipo, c4 trans. but the trans. needs work.

A friend wants to trade me his 91 F150 inline 6, 5spd. and a spare c5 trans. (from a 79 mustang), for my 79 truck.

I'm curious, whats the difference between the c4 and c5 trans? what issues to look out for with the c5? I'm told its tougher than the c4, is this so? I'm also told it will bolt right up to my 289 and bolt right up to the bird, is that true as well? Is the c5 a divorced bell housing trans. or is it all one piece? are any of the parts interchangeable between the c4 and c5 transmissions?

sorry for so many questions but I know, almost, absolutely nothing about transmissions.

needing opinions on a c5 trans.

Reply #1 – August 19, 2009, 07:28:39 PM

If its the original trans in the mustang, it isnt a c5, its a c4.

A c5 is the same as a c4, except it is metric and has a lockup converter.

needing opinions on a c5 trans.

Reply #2 – August 19, 2009, 08:30:38 PM

what is a lockup converter? is that the same as a torque converter? if so, whats the difference? and whats different on them that is metric vs. standard?

again, I'm an idiot when it comes to transmissions, sorry about that. lol

needing opinions on a c5 trans.

Reply #3 – August 19, 2009, 09:30:50 PM

A normal torque converter is always slipping when you're driving. A slipping converter is wasting fuel, so the C5 (and any modern automatic) has a lockup feature, where the converter has an internal clutch that locks up under certain conditions (light throttle, steady-state cruising, etc). The eliminated slippage gives you better fuel economy (almost, but not quite as good as having an overdrive gear). It also helps keep trans temperatures down, because slippage creates heat.

needing opinions on a c5 trans.

Reply #4 – August 19, 2009, 09:36:29 PM

so am I right to assume that the c5 is a better trans. than the c4? and, how many gears does a c5 have?

needing opinions on a c5 trans.

Reply #5 – August 20, 2009, 12:09:54 AM

just talked to the guy again, he said that even if I didnt want to traid the truck for his truck and trans. he'd sell me the c5 dirt cheap. is it worth swapping the c4 for the c5?

needing opinions on a c5 trans.

Reply #6 – August 20, 2009, 01:53:58 AM

I would verify via the oil pan whether it is actually a C5 or not due to the year vehicle it came out of, as it is right on the edge of the change in transmissions.

But IF IT IS, and the torque converter is correct for your application, I still wouldn't use it without a shift kit. :)

I have one in my 'Bird, and I would rather have a 5-Speed. But if you aren't hotrodding it, it will do ok. Your fuel economy will probably suck a LITTLE less, assuming it has the correct torque converter. I have heard rumors that the centrifugal lockup converter is no longer made, but that is so far just a rumor.

http://mmerlinn.tripod.com/trans/notes/fbbnotfd.htm

Scroll Down to C4/C5 Nomenclature. This site contains good info on the two, as well as links to others to increase your understanding.

needing opinions on a c5 trans.

Reply #7 – August 20, 2009, 02:15:52 AM

shift kit? what type? do you mean a upgrading the trans. with some kind of kit, or an aftermarket shifter kit? I dont have a kick down cable, so I'll be buying an aftermarket shifter no matter what the transmission is. if thats what your talking about.

needing opinions on a c5 trans.

Reply #8 – August 20, 2009, 02:31:47 AM

Oh yes, in the trans. there are several brands out there, mine is either a B&M or a Transgo kit. It is supposed to increase the line pressure and firm up the shifts.

Don't forget to flush your current radiator/trans cooler, or bypass it altogether with an aftermarket one so you don't contaminate your "new" transmission with whatever was wrong in your old one. Although the point is probably moot since it is used. How many miles are on the trans you want to get?

If you are having trouble understanding anything about the transmission, you could always ask around the local trans shops. Either get multiple opinions, or find one you trust. Most of the time advice is free :D

needing opinions on a c5 trans.

Reply #9 – August 20, 2009, 06:47:49 AM

C5 is a light duty trans, not recommended for a performance application without internal upgrades.

You have a manual trans now, why not go to a T5? Simple swap and you get overdrive. A 5 speed manual is a far better choice than a C5 and there are many available at a reasonable price.

needing opinions on a c5 trans.

Reply #10 – August 20, 2009, 11:14:49 AM

no, its a c4 auto

needing opinions on a c5 trans.

Reply #11 – August 20, 2009, 04:16:43 PM

I am running a c5 in my 302 T-bird and have had no problems, since I had it built up a bit.the c5 is every bit as good as the c4, if it is upgraded properly.

for $650.00 I had a extra clutch pack put in,shift kit,all new seals, lockup removed from my converter,had the stall changed to 2200-2500 and a H servo put in it.

this guy gave me a 2 year warranty ,up to 400 hp (although I dont have that much).

Hope this helps in some way.

needing opinions on a c5 trans.

Reply #12 – August 20, 2009, 05:56:24 PM

well let me ask you this, do you think the c5 would work ok, the way it is, untill I can get the c4 thats in it now fixed? We're talking within 6 months, 8 tops.

Or could it be an instant "SNAP" and break down, instead of a slow gradual breaking down?

needing opinions on a c5 trans.

Reply #13 – August 20, 2009, 06:34:19 PM

Imo a c5 would be better overall than a c4, especially for driveability. Im sure you can do the same mods to it to strengthen it.

A c5 is not a light duty trans, thats the c3. A c5 is just as strong as a c4.

needing opinions on a c5 trans.

Reply #14 – August 20, 2009, 07:47:13 PM

Quote from: shameless;287349

well let me ask you this, do you think the c5 would work ok, the way it is, untill I can get the c4 thats in it now fixed? We're talking within 6 months, 8 tops.

Or could it be an instant "SNAP" and break down, instead of a slow gradual breaking down?

as long as the c5 has no issues,I would say use it ,but treat it nicely (dont abuse it) until you can either upgrade it or get a good c4.

do you use this car as a daily driver?