Guys
I am thinking of embarking upon a gearbox rebuild with a friend. I am utterly clueless about the subject, but I have bought a rebuild manual to read.
My question is, which rebuild kit do you recommend. Over-specification of parts is fine by me, and my googling turned up this pricey little number:
https://www.summitracing.com/int/par...5021/overview/


Two of the comments said it did not have everything needed, and that a "Torrington bearing" and a Roller clutch/sprag" had to be bought separately.
Can anyone give me any advice or guidance on the best parts to buy please?


Thanks to all
Greg

 

Greg,

I went that road a looooong time ago.

NOPE.

Dropped the trans in the boot of the S2, and went to the trans guy, and handballed that sucker.

Told him all the details,kms, noises, etc. and he sorted it, and the convertor, and its still in that car.

I know many have done their own, but I am not that brave, and if you get it wrong, its not a 5 minute task to rip it out again.

 

I'm with Grant on this one, I bought a rebuild kit and a pile of Heavy Duty parts for my 4L60e. I did pull the 60 apart but with all the special tools needed to put the thing back together I also handballed it to a specialist.

 

With my 5hp24 I'm heading off to a specialist as well... Not that I don't dare to repair it myself, I just can't be arsed to, if I do something wrong, remove it and rebuild it again...

 

I rebuilt the 4L80E in my xjrs and it really was not the headache l was expecting. Bought a book covering the subject, that along with the wealth of knowledge available on line made the whole process a breeze.
Very important to be super methodical as you proceed.

 

OK guys, I'll think it over! I have a spare gearbox and plenty of long winter evenings, so common sense might be ignored....


But in the meantime, has anyone got an idea about what a roller clutch/sprag is? and what a Torrington bearing is?!!
Greg

 

@ Greg

Looks like a simple needle roller bearing... Nothing else!? At least the Torrington bearing. (Google says so)

 

A sprag is a one-way 'clutch' that rotates in one direction but not the other. A somewhat common weak point on the TH400

Transmission Components: Examining the One Way Clutch

There are various Torrington bearings; ones in transmissions usually look like this

http://www.bearingsg.com/wp-content/...jswwdl3rky.jpg


Cheers
DD

 

I'm with Grant....not brave enough

But that's no reason you shouldn't give it a whirl

Cheers
DD

 

Looks good to me.

Tons and tons of transmission parts suppliers who will ship anywhere. Summit might have what you need, they're a good supplier.

Bearings, drums, gears, sprags....things like that...are often referred to as "hard parts". Not always needed in an overhaul so not included in the kits. This keeps prices down.

Typical overhaul kits include "soft parts"...clutch plates, seals, gasket, bushings, and the like. Wear items; consumables.

If you overhaul a transmission *before* it is too far gone you can usually get by with just the overhaul kit. This is often called a "soft parts overhaul". If you wait too long before overhaul then actual damage (as opposed to just wear) can occur and you'll need a "hard parts overhaul". You typically buy hard parts only as-needed as things can start getting expensive.

There is SO much information on TH400s out there you'll have a hard time sorting thru it all. Lots of upgrades to consider....but don't get too bogged down in that stuff as lots of it is needed for racing applications only.

You'll need to decide on a torque converter as well

Cheers
DD

 

Years ago I was the Ford C4/C6 guy in a dealership. Auto transmissions are not any more complicated than some carburetor rebuilds. It's just when you make a mistake the do over is more time and money consuming. I've never been into a TH400. If it was a C4/C6 you would need a dial indicator for end play measurement and you might need to make a couple special mounts for it. An "inch*lb torque wrench is required to adjust bands. Most other special tools make the job easier but not impossible.

 

I'd also look on Rockauto.com for a kit. Their shipping to Europe is fairly reasonable too. They key to rebuilding a transmission is to take your time, make sure everything is EXACTLY to specification in terms of clearances and and have your work area operating room clean.

Often what you can do to make a transmission stronger is add an extra friction and steel to the clutch pack, say going from 5 to 6 friction plates (or whatever the number is).

Also you can often test operation as you go with air to activate the clutches. Be methodical and you'll be fine.

 

I have not done a complete rebuild myself, but helped a friend do a Ford 4R70W from a Lincoln Mark VIII. It's not that difficult if you have a good manual, follow the instructions and measurements and make sure everything is in specification.

As the saying goes, you eat an elephant one bite at a time.

 

Other thing I just thought of, is replace your wave plates in the clutch pack no matter what they look like. They seem to break at ~100,000 miles.

 

http://www.sonnax.com/tech_resources/237-playing-with-transmissions-setting-total-endplay-to-prevent-th400-gear-train-failure

this article helped me with my 4l80e

 

Thanks for all the points guys, I really appreciate it. I have bought a manual:
Which google said was the best one, and was well reviewed on Amazon. I have the Ron Sessions manual too, but when I read it some years ago, I felt it was not sufficiently step by step for me.
Greg

 

Thanks kindly for the link, it has good info. I intend at present to start with the Th400 and taller tires. I understand from the Buick folks that Switch-Pitch is still well-esteemed. I had one in my '66 Cadillac and it seems to be a good start before going deeper with a gearbox exchange.
Cheers!

 

i did a full rebuild on my own in my own workshop

a few specialist tools had to be bought

and i also took the opportunity to upgrade the GM400 to my requirements

a thread on this very site covers it from start to finish

https://www.jaguarforums.com/forum/x...ission-133739/

BB

 

I run 190 deg. thermostats with jiggle pins. If your trips are short they may never open.
If they are real short, you also may never get into open loop mode. I have had some success with slime for tires in the past.

 

Hi Greg, I guess I'm a bit late to the party here, but yes if you have space, the ability to keep bits clean, and the ability to really clean the parts with solvent/air a rebuild should be no issue. You'll want at least one special tool (not expensive) which is a particular spring compressor for the direct drum springs (pita without it). This kind of thing: https://www.otctools.com/products/au...ing-compressor.

I rebuilt mine many many years ago, it it may be that far more upgrade parts are available than I used. You have the Ron Sessions book, which is what I used, so I think you're in a very very good place. It's an older book and I can't say one way or another if a more newly published one would elucidate what's new that's available and what are the best kits. I can't remember how much the books talk about adding extra clutches, but it is possible as long as the clearances are kept the same.

You definitely have the right *base* rebuild book. It would be good so supplement it with some of the high performance books that tell you some of the particular bits to upgrade (like that Torrington bearing & sprag). I had a transmission wholesale/retail parts place about 30 minutes away so I was able to just go ask for the bits in Ron's book.

Make sure your front pump is good (good surfaces) and all sealing/seal riding surfaces are good / cleaned up with scotch bright, watch the many youtube vids on the subject, and you should be in better shape than I was. BTW I think there's some discussion on various forums about what's the best brand of clutches to get. I've heard that there some 4L80e builders (lots of similarities) use Allison clutches in one of the packs. So... *shrug* it's been a long time for me. I'd be hunting the web to answer new questions I didn't even think to ask / couldn't ask (pre internet) back then.

~Paul K.