th350 overhaul direct/forward clutch clearance

[Davidj]

i've been following along with @NickTransmissions videos and i'm at the part where i measure clearances for the direct and forward clutches. so far, this is what i've got

Direct clutch has 4 frictions, 5 steels. feeler gauge .25 can just fit. pressure plate has 1 indicator mark. (originally this was in the forward assebly.)

forward clutch has the wave plate, 5 frictions, 5 steels and .25 feeler gauge slips in without depressing wave plate. seems i can get about .5 if depressing the wave plate fully. pressure plate has 0 indicator marks, only an "S" stamped on it. (originally in the forward assembly)

when i tried using the pressure plates in the places they originally came out from, i ended up witth about .75 clearance on both. adding an extra steel resulted in difficulties fitting a .10 feeler gauge in. my question is, Does this final result sound about right? i don' have a depth gauge so i can't do the air method in his videos. this is the best combination of frictions/steels/plates i could come up with to get under .40-50 and keep it over .15. just want some reassurance before moving forward. thanks in advance for all help! and thanks many many times over for @NickTransmissions videos. cant thank you enough. truly.

 

[NickTransmissions]

i've been following along with @NickTransmissions videos and i'm at the part where i measure clearances for the direct and forward clutches. so far, this is what i've got

Direct clutch has 4 frictions, 5 steels. feeler gauge .25 can just fit. pressure plate has 1 indicator mark. (originally this was in the forward assebly.)

forward clutch has the wave plate, 5 frictions, 5 steels and .25 feeler gauge slips in without depressing wave plate. seems i can get about .5 if depressing the wave plate fully. pressure plate has 0 indicator marks, only an "S" stamped on it. (originally in the forward assembly)

when i tried using the pressure plates in the places they originally came out from, i ended up witth about .75 clearance on both. adding an extra steel resulted in difficulties fitting a .10 feeler gauge in. my question is, Does this final result sound about right? i don' have a depth gauge so i can't do the air method in his videos. this is the best combination of frictions/steels/plates i could come up with to get under .40-50 and keep it over .15. just want some reassurance before moving forward. thanks in advance for all help! and thanks many many times over for @NickTransmissions videos. cant thank you enough. truly.

Direct clutch should have four (4) frictions & four steels, unless you're counting a wavy/cushion steel...Direct clutch clearance should be fine at .025-.030"...Book calls for .015-.095" but I feel anything more than .060" is somewhat excessive if using a 4&4 set up...Your 2-3 shift will be on the quick side which is good for reducing slip...Forward clutches are always on in any forward range position so you just need enough clearance to avoid drag in park/neutral and potential tie-ups when in reverse. Book calls for .010-.080" so you should be ok if you have .025-.030".

Squeezing five (5) frictions and steels into either clutch usually requires you to machine the piston down and you want to be careful that you don't take too much off...If too much is taken off, the exterior lugs on the bottom steel may slip under the lugs on the drum and get caught, resulting in a 'no apply' condition in that clutch.

 

[Davidj]

Direct clutch should have four (4) frictions & four steels, unless you're counting a wavy/cushion steel...Direct clutch clearance should be fine at .025-.030"...Book calls for .015-.095" but I feel anything more than .060" is somewhat excessive if using a 4&4 set up...Your 2-3 shift will be on the quick side which is good for reducing slip...Forward clutches are always on in any forward range position so you just need enough clearance to avoid drag in park/neutral and potential tie-ups when in reverse. Book calls for .010-.080" so you should be ok if you have .025-.030".

Squeezing five (5) frictions and steels into either clutch usually requires you to machine the piston down and you want to be careful that you don't take too much off...If too much is taken off, the exterior lugs on the bottom steel may slip under the lugs on the drum and get caught, resulting in a 'no apply' condition in that clutch.

I have a feeling the forward clutch piston was machined at some point as I had no issues fitting 5 and 5 in along with the wave plate. The direct clutch on the other hand didn’t have a wave plate when I took it apart and 4 frictions, 4 steels came out. When I went to put the new ones in, it seemed a bit much at about .80-90 so I added an extra steel on the bottom of the stack resulting in the .25 clearance. In your opinion, should I look into purchasing a wave plate for the direct clutch as opposed to the extra steel? And is it abnormal to have 5 pairs in direct and 4 pairs in forward? If you don’t think this would cause any issues, I’d like to just keep it as is. This truck won’t be seeing any heavy towing or high rpm’s as my stepdad is quite light footed and this is a 2wd. Other than the question of the wave plate/extra steel, I feel pretty confident going forward now. Thanks for that. It’s greatly appreciated for my first rebuild.

 

[NickTransmissions]

I have a feeling the forward clutch piston was machined at some point as I had no issues fitting 5 and 5 in along with the wave plate. The direct clutch on the other hand didn’t have a wave plate when I took it apart and 4 frictions, 4 steels came out. When I went to put the new ones in, it seemed a bit much at about .80-90 so I added an extra steel on the bottom of the stack resulting in the .25 clearance. In your opinion, should I look into purchasing a wave plate for the direct clutch as opposed to the extra steel? And is it abnormal to have 5 pairs in direct and 4 pairs in forward? If you don’t think this would cause any issues, I’d like to just keep it as is. This truck won’t be seeing any heavy towing or high rpm’s as my stepdad is quite light footed and this is a 2wd. Other than the question of the wave plate/extra steel, I feel pretty confident going forward now. Thanks for that. It’s greatly appreciated for my first rebuild.

I'm generally not a fan of stacking steels on top of each other as you have but I don't think it will hurt anything. There's also .090 thick steels available as well as the thicker backing plates, unless you already have five .090 thick steels installed...If so, that piston was prob machined as well and I'd try to fit a 5-clutch, 5-steel set up...Interesting...

 

[Davidj]

I'm generally not a fan of stacking steels on top of each other as you have but I don't think it will hurt anything. There's also .090 thick steels available as well as the thicker backing plates, unless you already have five .090 thick steels installed...If so, that piston was prob machined as well and I'd try to fit a 5-clutch, 5-steel set up...Interesting...

Using a set of vernier calipers, they seem to be .70 maybe originally they did have 4 and 4 but left that .80-.90 clearance. Not sure if you remember but my direct clutches were pretty smoked and my forwards were down to steels because of the cut piston seal. I’ll look into a set of .90 steels and see if that makes the difference. Either way, I’m still saving a lot by doing it myself and learning a ton along the way. As always much appreciated! You’re a godsend.

 

[NickTransmissions]

Using a set of vernier calipers, they seem to be .70 maybe originally they did have 4 and 4 but left that .80-.90 clearance. Not sure if you remember but my direct clutches were pretty smoked and my forwards were down to steels because of the cut piston seal. I’ll look into a set of .90 steels and see if that makes the difference. Either way, I’m still saving a lot by doing it myself and learning a ton along the way. As always much appreciated! You’re a godsend.

Of course I remember - I don't have Alzheimer's, at least not yet lol. Plus excessive clearance in that clutch was not likely the reason (or only reason) they burned up - the cause is likely multi-factoral). Yes, look into the .090 thick steels...If you have an addl two steels at .020" per steel in the pack that would bring your clearance down from .090" to .050". A third would give you a clearance of about .030". I would do that 100 times out of a 100 before I stacked two steels on top of each other but that's just me (some other builders will tell you it's fine).

And you're welcome - glad you are tackling this rebuild; I'm sure it will turn out great!

One other thing - If you haven't done so, look into Sonnax's boost valve kit. It's pricey but worth it, esp if you're concerned about high clutch failure.