Striped Threads in aluminum housing - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Second Series · 01-11-2016, 05:30 PM

I have a 1988 GMC K2500 with the 5-speed transmission. My knuckles hit the dash when I shift to 1st and 3rd. I unscrewed the dust boot to find the top bolts loose. It was leaking there when I got it so I put two longer screws in, I thought it would work, but no, Two of the Four bolt holes the threads in the aluminum housing are striped. The bolts are M6 x 1 x 25. Does anyone have a suggestion for a replacement bolt? Maybe a self tapping bolt that’s slightly larger?

Jeepwm69 · 01-12-2016, 11:44 AM

Helicoil or timesert would be the best way to fix it.

Second Series · 01-15-2016, 05:14 PM

I'm considering using Helicoils, but I'm concerned about the metal bits falling into the transmission. I could place a piece of tape under the hole to catch most of the shards. I would need to buy the kit, about $35.00. I watched a video about loctite form a thread, but that kit is about $26.00. Has anyone here used this product? I found permatex cold weld compound for $6.00 and plan on trying that. The video showed placing anti seize compound on the bolt followed by the metal epoxy. The bolt is inserted into the stripped housing, and removed after Five minutes. The epoxy cures, and the threads are better than new. Sounds simple enough.

Second Series · 01-19-2016, 03:02 PM

Well, the glue didn't work. I looked up the conversion from metric to inches and 6mm = .2362". 1/4 inch bolt will be bigger, and I found Two 1/4" self tapping sheet metal screws on my workbench. Now my transmission shifts solid and my knuckles don't hit the dash when I shift to 1st and 3rd.

Second Series · 07-26-2019, 11:33 AM

Well, that didn’t last long. It’s been awhile, but I have driven this truck a dozen times and the bad fix has gone bad. I have never installed a heli-coil, and cutting into an aluminum transmission case is intimidating. After a couple weeks of hemming and hawing, I gathered the supplies and jumped in. I opened it up:

Second Series · 07-26-2019, 11:34 AM

The two rear holes are the worst. I used a hand drill, the holes kept it perpendicular for the most part. I got a long T-handle for the tap:

01-11-2016, 05:30 PM	#1
Second Series Registered User Join Date: May 2015 Location: Tukwila Washington Posts: 385	Striped Threads in aluminum housing I have a 1988 GMC K2500 with the 5-speed transmission. My knuckles hit the dash when I shift to 1st and 3rd. I unscrewed the dust boot to find the top bolts loose. It was leaking there when I got it so I put two longer screws in, I thought it would work, but no, Two of the Four bolt holes the threads in the aluminum housing are striped. The bolts are M6 x 1 x 25. Does anyone have a suggestion for a replacement bolt? Maybe a self tapping bolt that’s slightly larger?

01-12-2016, 11:44 AM	#2
Jeepwm69 Registered User Join Date: Jan 2009 Location: Arkansas Posts: 679	Re: Striped Threads in aluminum housing Helicoil or timesert would be the best way to fix it.

01-15-2016, 05:14 PM	#3
Second Series Registered User Join Date: May 2015 Location: Tukwila Washington Posts: 385	Re: Striped Threads in aluminum housing I'm considering using Helicoils, but I'm concerned about the metal bits falling into the transmission. I could place a piece of tape under the hole to catch most of the shards. I would need to buy the kit, about $35.00. I watched a video about loctite form a thread, but that kit is about $26.00. Has anyone here used this product? I found permatex cold weld compound for $6.00 and plan on trying that. The video showed placing anti seize compound on the bolt followed by the metal epoxy. The bolt is inserted into the stripped housing, and removed after Five minutes. The epoxy cures, and the threads are better than new. Sounds simple enough.

01-19-2016, 03:02 PM	#4
Second Series Registered User Join Date: May 2015 Location: Tukwila Washington Posts: 385	Re: Striped Threads in aluminum housing Well, the glue didn't work. I looked up the conversion from metric to inches and 6mm = .2362". 1/4 inch bolt will be bigger, and I found Two 1/4" self tapping sheet metal screws on my workbench. Now my transmission shifts solid and my knuckles don't hit the dash when I shift to 1st and 3rd.

07-26-2019, 11:33 AM	#5
Second Series Registered User Join Date: May 2015 Location: Tukwila Washington Posts: 385	Re: Striped Threads in aluminum housing Well, that didn’t last long. It’s been awhile, but I have driven this truck a dozen times and the bad fix has gone bad. I have never installed a heli-coil, and cutting into an aluminum transmission case is intimidating. After a couple weeks of hemming and hawing, I gathered the supplies and jumped in. I opened it up: Attached Images __________________ '47 Panel to '88 K2500 Frame Swap Mechanical Speedometer Drive Solution 1947.2 1 ton Chevy Panel 1955.2 Chevy 6700 Bus/RV 1990 Chevy K1500

07-26-2019, 11:34 AM	#6
Second Series Registered User Join Date: May 2015 Location: Tukwila Washington Posts: 385	Re: Striped Threads in aluminum housing The two rear holes are the worst. I used a hand drill, the holes kept it perpendicular for the most part. I got a long T-handle for the tap: Attached Images __________________ '47 Panel to '88 K2500 Frame Swap Mechanical Speedometer Drive Solution 1947.2 1 ton Chevy Panel 1955.2 Chevy 6700 Bus/RV 1990 Chevy K1500



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