Hi all-
I could not find too many threads linking info or pictures so I wanted to add a few tips if you are going to tackle this job. It is pretty self explanatory as there are no instructions or DIY videos online but as always, an easy job can sometimes take 4x the time!
These are the steps I used for my 1996 K2500 with a 7.4/ 4L80
1. Remove the bottom two nut and washers from the stock mount located under the front suspension crossmember. You will need a 15mm socket.
2. Once removed, using a 4x4 or equivalent OSHA approved jack extension, jack from a solid spot (not the t-case housing or tranny pan!) on the transmission or transfer case. I found a nice place under the transfer case to jack from and lift the mount out of the holes (underside of stock mount has studs/ new poly has holes for bolts). I raised my transmission approx 4-5 inches... this will give you a little more room for removal of the top two bolts that secure the mount to tranny.
3. Place Jackstand under tranny or piece of wood inbetween crossmember as a safety to your jack (hand or finger chomper if jack fails!)
4. Remove two bolts securing stock mount to tranny... studs should be up and out of the suspension crossmember. These bolts use a 15mm socket as well.
5. Stock rubber mount should nearly fall out with second bolt removed and inspect stock mount. My truck has high miles (276k) and the stock mount was definitely toast as the rubber on one end had totally degreaded from the center rod and was very brittle to the touch... the mount was easy moved by hand and was long gone!
6. After tossing the old mount in the garbage, place the metal plate on top of the poly mount (I measured the height of both mounts and the poly mount for the 4l80 needed the top plate) and begin threading in the top two bolts FIRST that secure the mount to the transmission, again using a 15mm... thread in and hand tighten gently. I used a dab of red lock tite and cleaned the bolts before reinstalling as the were pretty oil soaked.
7. Slowly lower the new poly mount down to the cross member by releasing pressure on your jack. If you used a jackstand or piece of wood, remove before lowering.
8. My stock mount was just shot enough the the holes on the bottom of the crossmember were off about 3/8 on an inch side to side. If you try and bolt the poly mount into the crossmember first, there is a good chance you will not be able to get the bolts started up top (ask me how!). The transmission cross member has slots and the top of the mounts has holes hence, more wiggle room to align down below.
9. Using a jack handle or long pry bar, find a spot against the t-case or tranny that wont bend and gently pry in the direction you need to go to align. If you want to cheat, have a second person take a ratchet strap around transmission to frame and gently tighten as you pry until you shout good! This can be done with one person but some kung fu skills had to be used and I wish I had simply asked for assistance...
10. Once you see the gold zinc plated holes line up in the x member slots, take your two bolts complete with flat and lock washers and screw one in at a time by hand... since my truck is a K series and is 4x4, my new poly tranny mount used the two outer holes... my cross member strangely enough had the provision for the middle hole and the bolt hole did line up but I believe that is for 2wd trucks. I also used a dab of red lock tite as well. These bolts provided used a 14mm socket.
11. Searching the interwebs, I found some general torque specs to shoot for as the mount for the 4L60 and 80 are the same...
Transmission Mount to Transmission Bolt: 37 ft/lbs
Transmission Mount Retaining Nut 30 ft/lbs
I used 3/8 ratchet and guesstimated on the Mount to Tranny as once lowered, the torque adapter would not fit... I will post a few finished pics later.
This is not a hard job per say and was completed in my driveway on 35's and 4 inches of lift... I have little to zero rust and a multitude of oil leaks over the years so no liquid wrench or fire axes were needed. Just plan for 1.5 hours as aligning the tranny mount back up will depend on the state of your old/ previous/ rubber mount.
OK... on to the clampshell/ motor mounts... from what I have read it might be easiest to drink a beer and pay a local shop to do it. My truck has little to no documentation from stock to 250k (currently have 267k) so getting down and dirty on the ole' 7.4 oil covered nasty mounts might be worth a buck 50.
Thoughts or should I try and tackle solo with no lift?
I could not find too many threads linking info or pictures so I wanted to add a few tips if you are going to tackle this job. It is pretty self explanatory as there are no instructions or DIY videos online but as always, an easy job can sometimes take 4x the time!
These are the steps I used for my 1996 K2500 with a 7.4/ 4L80
1. Remove the bottom two nut and washers from the stock mount located under the front suspension crossmember. You will need a 15mm socket.
2. Once removed, using a 4x4 or equivalent OSHA approved jack extension, jack from a solid spot (not the t-case housing or tranny pan!) on the transmission or transfer case. I found a nice place under the transfer case to jack from and lift the mount out of the holes (underside of stock mount has studs/ new poly has holes for bolts). I raised my transmission approx 4-5 inches... this will give you a little more room for removal of the top two bolts that secure the mount to tranny.
3. Place Jackstand under tranny or piece of wood inbetween crossmember as a safety to your jack (hand or finger chomper if jack fails!)
4. Remove two bolts securing stock mount to tranny... studs should be up and out of the suspension crossmember. These bolts use a 15mm socket as well.
5. Stock rubber mount should nearly fall out with second bolt removed and inspect stock mount. My truck has high miles (276k) and the stock mount was definitely toast as the rubber on one end had totally degreaded from the center rod and was very brittle to the touch... the mount was easy moved by hand and was long gone!
6. After tossing the old mount in the garbage, place the metal plate on top of the poly mount (I measured the height of both mounts and the poly mount for the 4l80 needed the top plate) and begin threading in the top two bolts FIRST that secure the mount to the transmission, again using a 15mm... thread in and hand tighten gently. I used a dab of red lock tite and cleaned the bolts before reinstalling as the were pretty oil soaked.
7. Slowly lower the new poly mount down to the cross member by releasing pressure on your jack. If you used a jackstand or piece of wood, remove before lowering.
8. My stock mount was just shot enough the the holes on the bottom of the crossmember were off about 3/8 on an inch side to side. If you try and bolt the poly mount into the crossmember first, there is a good chance you will not be able to get the bolts started up top (ask me how!). The transmission cross member has slots and the top of the mounts has holes hence, more wiggle room to align down below.
9. Using a jack handle or long pry bar, find a spot against the t-case or tranny that wont bend and gently pry in the direction you need to go to align. If you want to cheat, have a second person take a ratchet strap around transmission to frame and gently tighten as you pry until you shout good! This can be done with one person but some kung fu skills had to be used and I wish I had simply asked for assistance...
10. Once you see the gold zinc plated holes line up in the x member slots, take your two bolts complete with flat and lock washers and screw one in at a time by hand... since my truck is a K series and is 4x4, my new poly tranny mount used the two outer holes... my cross member strangely enough had the provision for the middle hole and the bolt hole did line up but I believe that is for 2wd trucks. I also used a dab of red lock tite as well. These bolts provided used a 14mm socket.
11. Searching the interwebs, I found some general torque specs to shoot for as the mount for the 4L60 and 80 are the same...
Transmission Mount to Transmission Bolt: 37 ft/lbs
Transmission Mount Retaining Nut 30 ft/lbs
I used 3/8 ratchet and guesstimated on the Mount to Tranny as once lowered, the torque adapter would not fit... I will post a few finished pics later.
This is not a hard job per say and was completed in my driveway on 35's and 4 inches of lift... I have little to zero rust and a multitude of oil leaks over the years so no liquid wrench or fire axes were needed. Just plan for 1.5 hours as aligning the tranny mount back up will depend on the state of your old/ previous/ rubber mount.
OK... on to the clampshell/ motor mounts... from what I have read it might be easiest to drink a beer and pay a local shop to do it. My truck has little to no documentation from stock to 250k (currently have 267k) so getting down and dirty on the ole' 7.4 oil covered nasty mounts might be worth a buck 50.
Thoughts or should I try and tackle solo with no lift?
