Transmission gap

[jmenende]

Guys im freaking out. I just bought my first cucv and noticed a gap in the transmission case while i was changing the oil. The truck runs with no issues.

 

[NDT]

Looks like some screws fell out on the torque converter cover. Did someone stuff their blanket in there?

 

[jmenende]

Looks like some screws fell out on the torque converter cover. Did someone stuff their blanket in there?

No blanket, its painted blue. Do you happen to know the size and pitch of the screws and maybe the torque specs.

 

[Mullaney]

No blanket, its painted blue. Do you happen to know the size and pitch of the screws and maybe the torque specs.

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I have made EDITS with help from members here. Original info has been marked with "strike through text.

Should be a 3/8 course bolt Metric M8x1.25x20mm flanged head cap bolt (Thanks Sharecropper , NDT , and cucvrus ).
BE CAREFUL. Don't break that cast aluminum (pot-metal)

A 3/8 inch ratchet and extension with a 9/16" swivel socket should reach all the way around the bellhousing (transmission).
Turn a quarter turn, go to the next bolt. One by one in some order.
Nothing more than the palm of your hand on the ratchet.

Don't "crank" on those bolts until the gap is gone - or the most sickening "pop" sound you will ever hear - will make a really bad day.
IF THE BOLTS stop turning and the gap isn't closed, STOP and get help or ask a lot more questions!

 

[jmenende]

.
Should be a 3/8 course bolt.
BE CAREFUL. Don't break that cast aluminum (pot-metal)

A 3/8 inch ratchet and extension with a 9/16" swivel socket should reach all the way around the bellhousing (transmission).
Turn a quarter turn, go to the next bolt. One by one in some order.
Nothing more than the palm of your hand on the ratchet.

Don't "crank" on those bolts until the gap is gone - or the most sickening "pop" sound you will ever hear - will make a really bad day.

I just drove for 2 hours like that with no issues. What a releif that i caught it on time. Would it make a difference that my truck is lifted.?

 

[Mullaney]

I just drove for 2 hours like that with no issues. What a releif that i caught it on time. Would it make a difference that my truck is lifted.?

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Shouldn't matter if it is lifted.

I just wonder if the bolts that come up into the transmission (generally half inch bolts, 3/4 inch socket) are loose too - or if maybe they were too tight when the transmission bolts were installed. Those (generally two) bolts should be pointed straight up into the transmission mount, toward the back.

 

[NDT]

Pretty sure they are metric. I would remove one of the remaining ones and take it to the auto parts store to match up.

 

[Sharecropper]

Pretty sure they are metric. I would remove one of the remaining ones and take it to the auto parts store to match up.

I agree with NDT. Those bolts are indeed Metric. M8x1.25x20mm flanged head cap bolt. Available at McMaster Carr or KasCar https://real4wd.com/product/bolt-self-locking/ . Hope this helps.

 

[cucvrus]

The correct bolts that hold the transmission cover on are M10 1.5 pitch Metric. There are 6 of them. 3 on each side flange. The 2 small treaded holes in the transmission housing flange on the bottom are not used in this application. I can mail you the correct flange bolts if needed. While you are under there using a 9/16" swivel socket go around the bell to engine block bolts and check them to assure they are tight. When I find loose bolts I go on a tightening party search. Good Luck Take Care and Be Safe.

 

[MarcusOReallyus]

I'd be trying to figure out if everything is seated properly. Since it's driving fine, it's probably okay, but as already mentioned, this is a good place for a large bucket of BE CAREFUL! and a good helping of GO SLOW!

Scary stuff!

 

[jmenende]

Here is the wierd part. The torque cover has the right cucv part# of 14036187 but the only two bolts that align are the top ones. Im thinking the tranny was replaced and they used the old cover.

 

[JD4044M]

There are no holes for those bolts missing to screw into? The Blue is your Torque Converter showing thru the crack. No way should there be a gap the dirt/mud will fill it up fast off road. Check ALL the bolts on the Bell Housing to make sure there tight!!

 

[jmenende]

No holes visible to screw into. Im gonna try to put it in place with clamps and if it works i will drill holes.

There are no holes for those bolts missing to screw into? The Blue is your Torque showing thru the crack. No way should there be a gap the dirt/mud will fill it up fast off road. Check ALL the bolts on the Bell Housing to make sure there tight!!

 

[cucvrus]

I am thinking you have a 350 gas engine cover there.

 

[jmenende]

Cover says 14036187

 

[JD4044M]

Since your dealing with the TH400 Transmission I put my pictures I took to rebuild mine in a album. First transmission rebuild for me but been driving it since 2018 when I rebuilt it! I rebuilt it while waiting for Rebuilt one to get here! It was my 1979 Chevy 1 ton 4x4 dually's Transmission. Maybe it will help someone taking one apart or wondering if you want to even try to rebuild it. I found it easy but I remember how stuff goes back together or used too? Lot of pictures to post here.TH400 Album

 

[ehuppert]

Quick google of that GM number says it's correct cover. Trans case may have been replaced at some point. I wouldn't drill transmission case, but can you drill through cover to use the two bottom bolts? Only real purpose is to keep debris away from seals/rotating parts... nothing structural!

 

[chevymike]

Here is the wierd part. The torque cover has the right cucv part# of 14036187 but the only two bolts that align are the top ones. Im thinking the tranny was replaced and they used the old cover.

I think that is a 2WD trans case that was rebuilt into a 4x4 unit. That flange where those bolts should go through on the trans, is way too thin compared to a 4x4 trans case. Not sure if you can see it but on the upper right side of the case should be case in a HD letters. Here is a pic I found that shows the HD and the thick flange. I circled in red. This is the correct 4x4 TH400 case.

 

[jmenende]

I think that is a 2WD trans case that was rebuilt into a 4x4 unit. That flange where those bolts should go through on the trans, is way too thin compared to a 4x4 trans case. Not sure if you can see it but on the upper right side of the case should be case in a HD letters. Here is a pic I found that shows the HD and the thick flange. I circled in red. This is the correct 4x4 TH400 case.

View attachment 837685

Im going to feel her out and report back. Thanks

 

[cucvrus]

Just for the record. Not all CUCV's have the HD cast in the case. I have seen many without the HD embossed. And I have matched the numbers to the vehicle. The last 8 are stamped on the side of the bell and they matched with NO HD in the casting. I see no rhyme or reason for this. Your example my be correct. Good Luck.

This was the correct last numbers of my VIN. Not sure where the cutoff and what is what here. I seen it many times with and without.